Motor Neurone Disease (Amyotrophic Lateral Sclerosis)

1. Clinical Overview

Summary

Motor Neurone Disease (MND), known as Amyotrophic Lateral Sclerosis (ALS) in North America, is a rapidly progressive and invariably fatal neurodegenerative disease affecting upper and lower motor neurones. It causes progressive weakness, wasting, and spasticity while characteristically sparing sensation, eye movements, and sphincter function. Median survival from symptom onset is 2-5 years, with 20-30% surviving beyond 5 years. Management is multidisciplinary and focuses on maintaining quality of life, function, and symptom control. [1,2]

The hallmark of MND is the combination of upper motor neurone (UMN) and lower motor neurone (LMN) signs in the same body region, without sensory involvement. This distinguishes it from other neuromuscular conditions. Disease progression follows a regional spread pattern, typically beginning focally in one limb or bulbar region before generalizing. [3]

Key Facts

• Incidence: 1.5-2.7 per 100,000 per year; prevalence 4-8 per 100,000 worldwide. [4]
• Peak Onset: 55-75 years; mean age 64 years; rare before age 40.
• Sex Ratio: Male predominance (1.3-1.5:1) in sporadic cases; equal in familial.
• Genetics: 5-10% familial (C9orf72 most common mutation accounting for 40% of familial cases); 90-95% sporadic.
• Survival: Median 2-5 years from symptom onset; 10% survive > 10 years; 5% survive > 20 years.
• Hallmark: Combined UMN + LMN signs WITHOUT sensory involvement or sphincter disturbance.
• Disease-Modifying: Riluzole extends survival by 2-3 months; edaravone may slow functional decline.
• Respiratory Support: NIV extends survival by 7-15 months and improves quality of life.

Clinical Pearls

The Cardinal Rule: MND = UMN + LMN signs in the SAME body region WITHOUT sensory loss. If sensation is abnormal, consider another diagnosis (cervical myelopathy, subacute combined degeneration, multifocal motor neuropathy).

Split Hand Sign: Early preferential weakness and wasting of thenar muscles (APB, FPB) and first dorsal interosseous relative to hypothenar muscles. This pattern is highly specific to ALS (sensitivity 58%, specificity 88%) and reflects preferential involvement of the lateral over medial corticomotoneuronal pathways. [5]

Respiratory Failure: The most common cause of death in ALS. Monitor FVC every 3 months. A decline of > 5% per month indicates rapid respiratory deterioration. Orthopnoea, morning headaches, daytime somnolence, and paradoxical abdominal breathing are early warning signs of nocturnal hypoventilation requiring urgent assessment.

Emotional Lability (Pseudobulbar Affect): Affects 20-50% of patients. Characterized by pathological laughing or crying disproportionate to emotional stimulus or mood state. It is NOT depression and reflects UMN bulbar involvement. Treat with low-dose amitriptyline (10-50mg), SSRIs, or dextromethorphan/quinidine combination. [6]

Preserved Functions: Eye movements, sphincter control, and sensation remain intact even in advanced disease. If these are affected early, reconsider the diagnosis.

El Escorial vs Awaji Criteria: The Awaji criteria (2008) improve diagnostic sensitivity by giving equal weight to clinical and electrophysiological evidence of LMN degeneration, particularly recognizing fasciculation potentials as evidence of active denervation. [7]

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2. Epidemiology

Incidence and Demographics

• Global Incidence: 1.5-2.7 per 100,000 per year with geographic variation. [4,8]
• Prevalence: 4-8 per 100,000 (varies by region and case ascertainment methods).
• Lifetime Risk: Approximately 1 in 300-350 individuals.
• Peak Age: 55-75 years (mean 64); rare before 40 (juvenile ALS less than 25 years represents distinct entity).
• Sex: Male predominance 1.3-1.5:1 in sporadic cases; ratio equalizes in older age groups.
• Geographic Variation: Historically higher in Western Pacific foci (Guam, Kii Peninsula of Japan, West New Guinea) - now declining, suggesting environmental factors.
• Ethnic Variation: Slightly higher in Caucasian populations; lower in Asian and African populations.

Risk Factors

Protective Factors:

• Female sex hormones (pre-menopausal protective effect) [10]
• Higher education (possibly detection bias)
• Mediterranean diet (epidemiological association)

MND Variants by Presentation

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3. Pathophysiology

Step 1: Motor Neurone Vulnerability

Cells Affected

• Upper Motor Neurones (UMN): Betz cells in motor cortex (layer V); corticospinal and corticobulbar tracts.
• Lower Motor Neurones (LMN): Anterior horn cells (spinal cord); motor nuclei of cranial nerves (V, VII, IX-XII in brainstem).

Selective Vulnerability Motor neurones are particularly vulnerable due to:

• High metabolic demands (large cell bodies, long axons up to 1 meter)
• Low calcium buffering capacity (susceptible to excitotoxicity)
• High levels of RNA metabolism and protein synthesis
• Limited regenerative capacity in adults
• Exposure to oxidative stress from high metabolic rate

Spared Populations (Onuf's Rule)

• Oculomotor nuclei (CN III, IV, VI): Eye movements preserved even in advanced disease
• Onuf's nucleus (S2-S4): Sphincter control maintained
• Parasympathetic neurones: Autonomic function preserved
• Mechanism of sparing unclear; possibly related to expression of neuroprotective factors

Step 2: Molecular Mechanisms

Protein Aggregation and Misfolding

• TDP-43 (TAR DNA-binding protein 43): Cytoplasmic inclusions in > 97% of ALS cases; normally nuclear protein; pathological cytoplasmic aggregation impairs RNA processing. [11]
• SOD1 (Superoxide Dismutase 1): Misfolded aggregates in SOD1-mutant familial ALS (~2% of all cases); gain of toxic function rather than loss of function.
• FUS (Fused in Sarcoma): Cytoplasmic inclusions in FUS-mutant cases; similar to TDP-43 in function.
• Dipeptide Repeat Proteins (DPRs): Produced by repeat-associated non-ATG translation in C9orf72 expansion; toxic to neurones.

RNA Metabolism Dysfunction

• C9orf72 Hexanucleotide Repeat Expansion: GGGGCC repeat in non-coding region (normal less than 30 repeats; pathological 700-1600+ repeats).
• Three mechanisms: [9]
  1. Loss of C9orf72 protein function (autophagy, endosomal trafficking)
  2. RNA toxicity (nuclear RNA foci sequester RNA-binding proteins)
  3. DPR protein toxicity (poly-GA, poly-GP, poly-GR, poly-PA, poly-PR)

Glutamate Excitotoxicity

• Excess glutamate in synaptic cleft → overstimulation of AMPA/NMDA receptors → excessive calcium influx → mitochondrial dysfunction → cell death.
• Reduced astrocytic glutamate transporter EAAT2 expression → impaired glutamate clearance.
• Riluzole mechanism: reduces glutamate release; blocks voltage-gated sodium channels.

Oxidative Stress and Mitochondrial Dysfunction

• Mitochondrial abnormalities: swelling, cristae disruption, reduced ATP production.
• Increased reactive oxygen species (ROS) production.
• Impaired antioxidant defenses.
• Mutant SOD1 directly damages mitochondria.

Axonal Transport Defects

• Impaired anterograde and retrograde transport of proteins, organelles, and neurotrophic factors.
• Dynein/kinesin motor protein dysfunction.
• Neurofilament accumulation in cell bodies and proximal axons.
• Distal "dying-back" axonopathy precedes cell body loss.

Neuroinflammation

• Microglial activation: initially neuroprotective, later neurotoxic (M1 phenotype).
• Reactive astrocytes: loss of neurotrophic support; gain of toxic function.
• Cytokine release (TNF-α, IL-1β, IL-6) contributes to motor neurone death.
• Peripheral immune system involvement: T-cell infiltration, altered regulatory T cells.

Prion-Like Propagation

• TDP-43 and SOD1 aggregates spread from cell to cell in prion-like manner. [12]
• Explains regional anatomical spread pattern.
• Potential therapeutic target (antibodies to misfolded proteins).

Step 3: Anatomic Progression

         TYPICAL LIMB-ONSET PROGRESSION
                     ↓
┌────────────────────────────────────────┐
│  STAGE 1: FOCAL ONSET                  │
│  One limb, one body region             │
│  e.g., Hand weakness with wasting      │
│  Duration: 6-12 months                 │
└────────────────────────────────────────┘
                     ↓
┌────────────────────────────────────────┐
│  STAGE 2: REGIONAL SPREAD              │
│  Ipsilateral limb, then contralateral  │
│  Follows corticospinal tract           │
│  Duration: 12-24 months from onset     │
└────────────────────────────────────────┘
                     ↓
┌────────────────────────────────────────┐
│  STAGE 3: GENERALIZATION               │
│  All four limbs affected               │
│  Bulbar involvement in 80%             │
│  Trunk and respiratory muscles         │
│  Duration: 24-48 months from onset     │
└────────────────────────────────────────┘
                     ↓
┌────────────────────────────────────────┐
│  STAGE 4: ADVANCED DISEASE             │
│  Respiratory muscle failure            │
│  Severe dysphagia requiring PEG        │
│  Anarthria; AAC devices needed         │
│  Duration: variable (months to years)  │
└────────────────────────────────────────┘
                     ↓
┌────────────────────────────────────────┐
│  STAGE 5: TERMINAL PHASE               │
│  Respiratory failure (Type 2 RF)       │
│  Complete paralysis except eyes        │
│  Locked-in state (rare)                │
└────────────────────────────────────────┘

Bulbar-Onset Progression: Begins with speech/swallowing difficulties → limb involvement within 12 months → respiratory failure earlier than limb-onset (worse prognosis).

Step 4: Clinical Consequences

UMN Degeneration

• Spasticity (velocity-dependent increase in tone)
• Hyperreflexia (brisk tendon reflexes even in weak, wasted muscles)
• Pathological reflexes (Babinski, Hoffman's signs)
• Clonus (sustained rhythmic contractions)
• Slowed fine motor movements
• Pseudobulbar affect (emotional lability)
• Dysarthria (spastic speech)

LMN Degeneration

• Weakness (progressive, asymmetric initially)
• Muscle wasting (atrophy)
• Fasciculations (visible muscle twitches; 70% of patients)
• Muscle cramps (painful, nocturnal)
• Hyporeflexia (when LMN loss predominates in isolation - seen in PMA)
• Flaccid dysarthria

Bulbar Involvement

• Dysarthria (spastic, flaccid, or mixed depending on UMN/LMN balance)
• Dysphagia (liquids then solids for LMN; opposite for UMN)
• Sialorrhoea (drooling due to impaired swallowing, not excess saliva)
• Weak cough (impaired airway protection)
• Tongue wasting and fasciculations
• Emotional lability

Respiratory Failure

• Diaphragm weakness → Type 2 respiratory failure (↑CO2)
• Nocturnal hypoventilation → morning headaches, daytime somnolence
• Orthopnoea (inability to lie flat)
• Weak cough → retained secretions → pneumonia
• Respiratory rate > 25/min at rest indicates impending failure

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4. Clinical Presentation

Cardinal Features

Upper Motor Neurone (UMN) Signs

• Spasticity: Velocity-dependent resistance to passive movement; "clasp-knife" phenomenon.
• Hyperreflexia: Brisk or pathologically increased tendon reflexes (even in weak, wasted muscles - key distinguishing feature).
• Pathological Reflexes: Babinski sign (upgoing plantar), Hoffman's sign (finger flexion reflex).
• Clonus: Sustained rhythmic contractions (ankle, patella, jaw).
• Increased Jaw Jerk: Exaggerated response indicates UMN bulbar involvement.
• Pseudobulbar Affect: Pathological laughing/crying; reflects bilateral UMN lesions.
• Slowed Movement: Bradykinesia of fine finger movements.

Lower Motor Neurone (LMN) Signs

• Weakness: Progressive, initially asymmetric; follows segmental/myotomal distribution.
• Muscle Wasting: Atrophy of affected muscles; out of proportion to disuse.
• Fasciculations: Spontaneous muscle twitches visible through skin; may precede weakness by months; 70% sensitive. [13]
• Muscle Cramps: Painful, often nocturnal; early symptom in 60%.
• Hyporeflexia/Areflexia: When LMN loss predominates (often masked by concurrent UMN involvement).
• Flaccid Tone: Reduced resistance to passive movement.

Symptoms by Onset Pattern

Detailed Symptom Analysis

Limb Symptoms

• Hand Weakness: Difficulty with buttons, keys, writing, grip strength; dropping objects.
• Split Hand Pattern: Preferential thenar (APB, FPB) and FDI wasting versus hypothenar sparing.
• Foot Drop: Tripping over uneven surfaces; difficulty with stairs; ankle instability.
• Proximal Weakness: Difficulty rising from chair, climbing stairs, lifting arms overhead (combing hair, reaching shelves).
• Muscle Cramps: Calf cramps at night; hand cramps during activity.
• Fasciculations: Visible twitching; may precede weakness; 70% of patients report.

Bulbar Symptoms

• Dysarthria:
  • "Spastic (UMN): strained, strangled quality; slow rate; harsh voice"
  • "Flaccid (LMN): nasal, breathy; reduced volume; hypernasality"
  • "Mixed: both features (most common)"
• Dysphagia:
  • "Liquids (LMN): nasal regurgitation, coughing with thin fluids"
  • "Solids (UMN): food sticking in throat"
  • Silent aspiration risk (reduced cough reflex)
• Sialorrhoea: Drooling due to reduced swallow frequency, not excess saliva production; worse when supine.
• Weak Cough: Impaired airway protection; secretion retention; aspiration pneumonia risk.
• Voice Changes: Hypernasality, reduced volume, vocal fatigue.

Respiratory Symptoms

• Orthopnoea: Difficulty lying flat; using multiple pillows; sleeping upright in chair.
• Morning Headaches: CO2 retention from nocturnal hypoventilation.
• Daytime Somnolence: Poor quality sleep due to hypercapnia.
• Dyspnoea on Exertion: Breathlessness with minimal activity; talking, eating.
• Weak Sniff: Reduced sniff nasal inspiratory pressure (SNIP) indicates diaphragm weakness.
• Paradoxical Breathing: Inward abdominal movement on inspiration (diaphragm paralysis).

Cognitive and Behavioral

• Executive Dysfunction: 35-50% have subtle deficits in planning, set-shifting, verbal fluency. [14]
• Behavioral Variant FTD: 10-15% develop frank frontotemporal dementia (disinhibition, apathy, perseveration).
• Language Impairment: Semantic dementia or progressive non-fluent aphasia in ALS-FTD.
• Emotional Lability: 20-50% have pseudobulbar affect (distinct from depression).
• Depression/Anxiety: 30-40% prevalence; screen regularly with PHQ-9, GAD-7.

What is SPARED (The "Untouched Functions")

Strictly Preserved Until Very Late/Never

1. Sensation: No numbness, paraesthesias, neuropathic pain (if present, reconsider diagnosis).
2. Eye Movements: External ocular muscles (CN III, IV, VI) spared even in locked-in state.
3. Sphincter Control: Bladder and bowel continence maintained (if lost early, consider multiple system atrophy).
4. Autonomic Function: Blood pressure, heart rate, sweating, sexual function intact.

Usually Preserved 5. Cognition: 50-65% have no cognitive impairment; 35% mild executive dysfunction; 15% FTD. [14] 6. Vision and Hearing: Sensory organs unaffected.

Red Flags - "The Don't Miss" Signs

Immediate/Urgent Assessment Required

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5. Clinical Examination

Systematic Neurological Examination

Inspection (Begin Before Touching Patient)

• Wasting: Hands (split hand sign), shoulder girdle (deltoid, supraspinatus), tongue (scalloped edges, atrophy), facial muscles.
• Fasciculations: Observe for 60 seconds in resting muscles; tongue (LMN bulbar), limbs, trunk; increased with gentle muscle percussion.
• Posture and Gait: Foot drop (high-stepping gait), wrist drop, head drop (neck extensor weakness), lordotic posture (compensating for proximal weakness).
• Respiratory: Tachypnoea (> 25/min), accessory muscle use, paradoxical abdominal breathing (diaphragm weakness).
• Drooling: Saliva pooling, wet chin, handkerchief use.

Tone

• UMN: Spasticity (velocity-dependent; "clasp-knife"); more in legs than arms typically.
• LMN: Hypotonia or normal (may be masked by concurrent UMN spasticity).
• Mixed: Most common; spasticity with reduced resistance at end-range.

Power (MRC Scale 0-5)

• Test all muscle groups systematically (proximal and distal; upper and lower limbs).
• Pattern Recognition:
  • "Classic ALS: distal > proximal initially; asymmetric"
  • "Split hand: APB/FDI weaker than ADM (little finger abduction)"
  • "Flail arm: proximal arms severely weak; legs spared early"
• Note: Apparent weakness may be limited by spasticity or pain.

Reflexes

• Hallmark: Brisk reflexes in wasted, weak muscles (UMN + LMN).
• Upper Limb: Biceps, supinator, triceps (often 3+ or 4+).
• Lower Limb: Knee, ankle (often 3-4+; ankle may be depressed if severe LMN).
• Jaw Jerk: Pathologically brisk = UMN bulbar involvement.
• Pathological Reflexes:
  • Hoffman's sign (flick middle finger → thumb flexion) = UMN upper limbs
  • Babinski sign (upgoing plantar) = UMN lower limbs
  • Ankle clonus (sustained rhythmic contractions) = UMN

Plantars

• Babinski Positive (extensor response): Upgoing hallux ± fanning of toes = UMN lesion.
• May be absent if severe LMN involvement of S1 segment.

Sensory Examination (MUST Be Normal)

• Light touch, pinprick, vibration, proprioception: ALL normal.
• If abnormal → reconsider diagnosis (myelopathy, peripheral neuropathy, B12 deficiency).

Coordination

• Finger-nose, heel-shin, rapid alternating movements: normal (unless limited by weakness/spasticity).
• Cerebellar signs absent (if present, consider multisystem degeneration).

Bulbar and Cranial Nerve Examination

Speech Assessment

• Spontaneous Speech: Rate, clarity, volume, quality.
• Spastic Dysarthria (UMN): Strained, strangled, slow, harsh.
• Flaccid Dysarthria (LMN): Nasal, breathy, reduced volume.
• Mixed: Combination (most common in ALS).
• Test Phrases: "British Constitution"
  • "Baby Hippopotamus"
  • "West Register Street" (assess labial, lingual, velar sounds).

Facial Examination (CN VII)

• Weakness usually mild; UMN pattern (forehead sparing) if present.
• Emotional lability: ask about inappropriate laughing/crying.

Bulbar Examination

• Tongue:
  • "Inspection: wasting (shrunken, wrinkled), fasciculations at rest (wait 60 seconds - pathognomonic LMN sign)"
  • "Movement: protrusion (deviation to weak side if LMN), side-to-side movement"
• Palate:
  • Elevation: say "Ahh" (symmetric elevation = normal; UMN causes brisk gag; LMN causes absent/asymmetric elevation)
  • "Gag reflex: brisk/exaggerated = UMN; reduced/absent = LMN"
• Jaw Jerk (CN V):
  • Place finger on chin; tap with reflex hammer; exaggerated = UMN bulbar
• Swallowing:
  • Ask about dysphagia (liquids vs solids)
  • Water swallow test (observe for coughing, wet voice after swallow)

Eye Movements (CN III, IV, VI) - MUST Be Normal

• Full range of eye movements preserved even in advanced ALS.
• If restricted, consider alternative diagnosis (progressive supranuclear palsy, myasthenia gravis).

Respiratory Assessment

Observation

• Respiratory rate (normal 12-20; > 25/min concerning)
• Use of accessory muscles (sternocleidomastoid, scalenes)
• Paradoxical abdominal breathing (abdomen moves in on inspiration = diaphragm paralysis)
• Orthopnoea (assess by asking: "How many pillows do you use?"; "Can you lie flat?")

Functional Tests

• Single Breath Count: Ask patient to count as far as possible on single breath (normal > 20; less than 10 severe impairment)
• Cough Strength: Ask patient to cough forcefully (assess audibility, airflow)
• Lying Flat Test: FVC drops ≥25% when supine = diaphragm weakness

Objective Measures

• Forced Vital Capacity (FVC): Bedside spirometry; normal > 80% predicted; less than 50% consider NIV
• Sniff Nasal Inspiratory Pressure (SNIP): Measures diaphragm strength; less than 40 cmH2O concerning
• Blood Gases: If symptomatic; raised CO2 (> 6 kPa / 45 mmHg) = Type 2 respiratory failure

Specific Diagnostic Signs

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6. Investigations

Electrophysiology (Essential for Diagnosis)

Electromyography (EMG) - Gold Standard for LMN Evidence

Findings Diagnostic of Active Denervation

• Fibrillation Potentials: Spontaneous single muscle fiber discharges; high-pitched sound.
• Positive Sharp Waves: Similar to fibrillations; sharp initial deflection.
• Fasciculation Potentials: Spontaneous motor unit discharges; larger amplitude than fibrillations; helpful when present in clinically normal muscles.

Findings Diagnostic of Chronic Reinnervation

• Large Amplitude Motor Units: > 5 mV (normal 1-2 mV); reflects collateral sprouting.
• Long Duration Motor Units: > 15 ms (normal 8-12 ms); polyphasic morphology.
• Reduced Recruitment: Fewer motor units firing at higher rates to generate force.

EMG Requirements for Diagnosis (Awaji Criteria) [7]

• Evidence of LMN degeneration in ≥2 regions (bulbar, cervical, thoracic, lumbosacral).
• Fasciculation potentials have equal weight to fibrillations/positive sharp waves (change from El Escorial).

Nerve Conduction Studies (NCS) - Exclude ALS Mimics

Motor Studies

• Compound Muscle Action Potential (CMAP) amplitudes: normal or reduced (proportional to LMN loss).
• Motor conduction velocities: normal or mildly reduced (less than 70% of normal may indicate demyelinating neuropathy - exclude multifocal motor neuropathy).
• No conduction block (presence suggests MMN, not ALS).
• Distal motor latencies: normal.

Sensory Studies - MUST Be Normal

• Sensory nerve action potentials (SNAPs): normal amplitude, velocity, latency.
• Abnormal sensory studies exclude ALS diagnosis (suggests peripheral neuropathy, radiculopathy, myelopathy).

Special EMG Techniques

• Motor Unit Number Estimation (MUNE): Quantifies surviving motor units; useful for tracking progression in trials.
• Neurophysiological Index (NI): Ratio of CMAP to distal motor latency; less than 40 suggests demyelination (exclude MMN).

Diagnostic Criteria

El Escorial Criteria (Revised 1998) [15]

Diagnostic Categories

Awaji Criteria (2008) [7] - Improved Sensitivity

• Gives equal weight to clinical and electrophysiological evidence of LMN degeneration.
• Fasciculation potentials on EMG = equivalent to fibrillations/positive sharp waves.
• Increases diagnostic sensitivity by 10-15% (especially early disease).

Exclusion Criteria (If Present, ALS Diagnosis Excluded)

• Sensory abnormalities beyond minor vibratory loss in elderly
• Sphincter dysfunction early in course
• Parkinsonism, dementia, or cerebellar signs (consider MSA-P, PSP)
• Isolated UMN or LMN syndrome beyond 4 years (PLS or PMA respectively)
• Multifocal motor neuropathy with conduction block on EMG
• Prominent autonomic dysfunction

Neuroimaging

MRI Brain and Cervical/Thoracic/Lumbar Spine

Indications

• Mandatory: Exclude structural mimics (cervical spondylotic myelopathy, foramen magnum lesion, cord tumour, syrinx).
• Additional Value: Support diagnosis with ALS-specific findings (low sensitivity, high specificity).

MRI Findings Supportive of ALS (Not Diagnostic Alone)

• T2 Hyperintensity: Corticospinal tracts from motor cortex to brainstem (30-50% of cases).
• Motor Cortex Atrophy: Thinning of precentral gyrus.
• T2 Hypointensity: Motor cortex (iron deposition from neurodegeneration).
• DTI (Diffusion Tensor Imaging): Reduced fractional anisotropy in corticospinal tracts (research tool).

Must Exclude

• Cervical stenosis with cord compression
• Foramen magnum lesions (meningioma, Chiari malformation)
• Multifocal demyelination (MS)
• Syringomyelia/syringobulbia
• Spinal tumours (intra- or extramedullary)

Blood Tests - Exclude ALS Mimics

Lumbar Puncture - Not Routine

• Indications: Atypical features; suspected inflammatory/infectious mimic.
• CSF in ALS: Protein normal or mildly elevated (less than 1 g/L); cells less than 5; oligoclonal bands absent.
• Red Flags: Elevated protein > 1 g/L suggests CIDP; pleocytosis suggests infection/inflammation.

Respiratory Function Tests

Forced Vital Capacity (FVC) - Essential Monitoring

Measurement

• Bedside spirometry; sitting and supine (postural drop ≥25% = diaphragm weakness).
• Frequency: every 3 months; every month if FVC less than 60%.

Interpretation

• Normal: > 80% predicted
• Mild Impairment: 60-80% predicted (monitor closely)
• Moderate Impairment: 50-60% predicted (discuss NIV; consider timing for PEG if needed)
• Severe Impairment: less than 50% predicted (NIV indicated; high procedural risk for PEG)
• Critical: less than 30% predicted (urgent NIV; terminal care planning)

Rate of Decline

• Slow: less than 3% decline per month
• Moderate: 3-5% per month
• Fast: > 5% per month (poor prognosis; urgent respiratory input)

Sniff Nasal Inspiratory Pressure (SNIP)

• Measures diaphragm strength specifically.
• Normal: > 60 cmH2O (women), > 70 cmH2O (men)
• Concerning: less than 40 cmH2O
• Correlates better with nocturnal hypoventilation than FVC in some patients

Peak Cough Flow (PCF)

• Measures ability to clear secretions.
• Normal: > 270 L/min
• Impaired: less than 270 L/min (cough assist device may help)
• Severely impaired: less than 160 L/min (high aspiration risk)

Arterial Blood Gases (ABG) / Capillary Blood Gases

• Indications: FVC less than 50%, symptomatic (orthopnoea, headaches), before NIV initiation.
• Key Finding: Type 2 respiratory failure (PaCO2 > 6 kPa / 45 mmHg; PaO2 low-normal)
• Rising CO2 = urgent NIV

Overnight Oximetry / Polysomnography

• Detects nocturnal hypoventilation before daytime symptoms.
• Oxygen desaturations less than 90% for > 10% of night = abnormal.
• Consider when FVC 50-70% or symptoms of sleep disturbance.

Genetic Testing

Indications

• Family history of ALS or FTD (first- or second-degree relatives)
• Young onset (less than 40 years)
• Atypical features (very slow progression, predominant UMN)
• Patient request for family planning
• Consideration for mutation-specific therapies (e.g., tofersen for SOD1)

Common Genes Tested [9,16]

Testing Process

• Genetic counseling mandatory (pre- and post-test)
• Informed consent (implications for insurance, employment, family)
• Panel testing (multiple genes) or targeted testing (known family mutation)
• Turnaround time: 4-8 weeks typically
• Reimbursement varies by jurisdiction (often covered if family history)

Genetic Counseling Considerations

• Presymptomatic testing in at-risk relatives (ethical complexities)
• Implications for children and extended family
• Reproductive options (PGD - preimplantation genetic diagnosis)
• Life insurance and employment discrimination concerns
• Psychological impact of positive result without curative treatment

Biomarkers [33,34]

Neurofilament Light Chain (NfL) - Most Promising Biomarker

Description

• Structural protein released from damaged axons
• Measured in blood (serum/plasma) or CSF
• Reflects neurodegeneration rate across CNS diseases

Utility in ALS

• Diagnosis: Elevated NfL supports but does not confirm ALS (sensitivity ~80%, specificity ~70% vs healthy controls)
• Prognosis: Higher baseline NfL correlates with faster progression and shorter survival
• Monitoring: Rate of NfL rise tracks disease activity
• Treatment Response: Used as outcome measure in clinical trials (e.g., tofersen trial showed 55% reduction in NfL)

Levels

• Healthy adults: less than 10-20 pg/ml (age-dependent)
• ALS patients: typically 50-300 pg/ml (wide range)
• Very high levels (\u003e 200 pg/ml) = poor prognosis

Limitations

• Not specific to ALS (elevated in MS, stroke, Alzheimer's, normal aging)
• Not yet routinely available outside specialist centers/trials
• Requires specialized assay (Simoa, Ella platforms)

Phosphorylated Neurofilament Heavy Chain (pNfH)

• Alternative neurofilament marker; CSF measurement
• Similar utility to NfL but less widely studied
• Elevated in ALS vs controls

Other Emerging Biomarkers

Clinical Use (2026)

• NfL increasingly used in trials but NOT routine clinical practice
• No biomarker currently replaces clinical diagnosis (Awaji criteria remain gold standard)
• Future: NfL may stratify patients for trials, monitor treatment response

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7. Management

Multidisciplinary Team (MDT) Care - Gold Standard [17]

Core Team Members

Evidence for MDT Care

• Specialist MDT clinics improve survival (7-12 month increase). [17]
• Improved quality of life scores
• Better symptom control
• Higher rates of NIV/PEG uptake
• Fewer emergency admissions

Clinic Frequency

• Every 3 months standard
• Every 1-2 months if rapid progression or FVC less than 60%
• Telephone/virtual clinics between face-to-face

Disease-Modifying Therapies

Riluzole [18]

Mechanism

• Antiglutamatergic: reduces presynaptic glutamate release
• Blocks voltage-gated sodium channels
• Neuroprotective via reduction of excitotoxicity

Evidence

• Meta-analysis of RCTs: extends survival by 2-3 months at 12-18 months. [18]
• No significant effect on muscle strength or functional decline rate
• Modest delay to tracheostomy
• NNT = 13 to prevent one death at 12 months

Dosing

• 50 mg twice daily (BD), 12 hours apart
• Take 1 hour before or 2 hours after food (food reduces absorption)
• Start at diagnosis; continue indefinitely (unless intolerable side effects or patient choice to stop)

Side Effects

• Nausea (10-15%): usually settles in 2-4 weeks
• Fatigue, dizziness (10%)
• Hepatotoxicity (rare but important): monitor ALT monthly for 3 months, then 3-monthly
  • Stop if ALT > 5× ULN
  • Restart at lower dose if ALT normalizes

Monitoring

• Baseline LFTs (ALT, AST)
• Monthly LFTs for first 3 months
• 3-monthly LFTs thereafter
• Stop if ALT > 5× ULN or patient develops jaundice

Contraindications

• Hepatic impairment (Child-Pugh B or C)
• ALT > 3× ULN at baseline
• Pregnancy/breastfeeding (avoid; category C)

Edaravone (Radicava) [19]

Mechanism

• Free radical scavenger; antioxidant
• Reduces oxidative stress-mediated neuronal injury

Evidence

• Japanese RCT: slowed functional decline (ALSFRS-R) by 2.5 points over 6 months in selected patients. [19]
• Subsequent trials showed inconsistent benefit
• FDA approved (USA); limited availability in UK/Europe (not NICE approved)
• Very strict inclusion criteria: FVC > 80%, disease duration less than 2 years, minimal disability

Dosing

• IV infusion: 60 mg daily for 14 days, then 14-day drug-free period; repeat cycle
• Requires IV access and regular hospital/clinic attendance

Side Effects

• Bruising, gait disturbance, headache
• Allergic reactions (discontinue if occurs)

Limitations

• Inconvenient administration (daily IV for 2 weeks per month)
• High cost
• Uncertain benefit outside highly selected trial population
• Not routinely funded in UK NHS

Tofersen (Qalsody) [31]

Mechanism

• Antisense oligonucleotide (ASO) targeting SOD1 mRNA
• Reduces production of mutant SOD1 protein
• Administered intrathecally (into CSF via lumbar puncture)

Indications

• SOD1-mutation confirmed ALS only (affects ~2% of all ALS cases; 15-20% of familial)
• FDA approved 2023; conditional approval in Europe

Evidence

• Phase 3 trial: reduced neurofilament light chain (biomarker of neurodegeneration) by 55%
• Slowed functional decline by 1-2 ALSFRS-R points over 28 weeks in slower progressors
• Open-label extension showed sustained benefit
• Most effective in presymptomatic or very early disease

Dosing

• Loading: 100 mg intrathecal on days 1, 15, 29
• Maintenance: 100 mg intrathecal every 28 days indefinitely

Side Effects

• Lumbar puncture complications (headache, infection, bleeding)
• CSF protein elevation
• Myelitis (rare but serious)

Limitations

• Requires confirmed SOD1 mutation (genetic testing mandatory)
• Invasive administration (monthly lumbar punctures)
• Very high cost (~$150,000/year)
• Only benefits small subset of ALS population

AMX0035 (Sodium Phenylbutyrate/Taurursodiol; Relyvrio/Albrioza) [32]

Mechanism

• Dual-action: reduces ER stress and mitochondrial dysfunction
• Sodium phenylbutyrate: chemical chaperone, reduces protein misfolding
• Taurursodiol (TUDCA): bile acid, stabilizes mitochondria

Evidence

• CENTAUR trial: slowed ALSFRS-R decline by 2.3 points over 24 weeks
• Post-approval trial (PHOENIX) failed to show benefit (2024) → FDA requested voluntary withdrawal
• Currently undergoing regulatory review; availability uncertain

Dosing (when available)

• Oral sachets: phenylbutyrate 3g + taurursodiol 1g, twice daily
• Mix with water or via PEG

Status

• FDA approved September 2022; withdrawn April 2024 after negative Phase 3 data
• Lessons: highlighted challenges of ALS drug development; importance of confirmatory trials
• Represents fastest FDA approval to withdrawal in ALS history

Gene Therapy and Emerging Therapies (2026)

• AAV-mediated gene therapy: Trials for C9orf72, SOD1; delivery challenges to CNS
• Stem cell therapy: Neural progenitor cells; Phase 2/3 trials; no proven benefit yet
• Antibody therapies: Anti-misfolded SOD1, anti-TDP-43; preclinical/early clinical
• Small molecules: Masitinib (tyrosine kinase inhibitor); Phase 3 ongoing
• Antisense oligonucleotides: Targeting C9orf72, FUS, ATXN2; multiple trials

Symptomatic Management

Spasticity

Muscle Cramps

Sialorrhoea (Drooling)

Thick Secretions

Pseudobulbar Affect (Emotional Lability)

Pain

Depression and Anxiety

Respiratory Support [20]

Non-Invasive Ventilation (NIV) - Extends Survival and Improves QoL

Indications (Any One of) [20]

• FVC less than 50% predicted
• SNIP less than 40 cmH2O
• Orthopnoea with postural FVC drop > 25%
• Symptomatic nocturnal hypoventilation (morning headaches, daytime somnolence)
• Blood gases showing hypercapnia (PaCO2 > 6 kPa / 45 mmHg)

Evidence

• RCT: NIV improves median survival by 7 months (16 months vs 9 months). [20]
• Quality of life improved (sleep quality, dyspnoea, mental health)
• Sub-group analysis: greater benefit in non-bulbar onset (15 month increase vs 3 months in bulbar)

NIV Setup

• Mode: BiPAP (bilevel positive airway pressure); IPAP/EPAP typically 12-16/4-6 cmH2O
• Interface: Nasal mask preferred (less claustrophobic, allows speech); full-face mask if mouth breathing
• Initiation: Respiratory physiologist/specialist nurse; acclimatization period
• Duration: Start nocturnal (8 hours/night); extend to daytime as disease progresses; eventual 24-hour use in some

Monitoring NIV Efficacy

• Symptom improvement (headaches resolve, sleep quality improves)
• Compliance (hours/night on NIV machine data)
• Repeat ABG (normalization of CO2)
• Oxygen saturations overnight (reduce desaturations)

Challenges

• Bulbar weakness: difficulty tolerating mask; air leaks; secretion management
• Claustrophobia: gradual acclimatization; different mask trials
• Skin breakdown: pressure relief; regular mask repositioning
• Non-compliance: education; involvement of carer; multidisciplinary support

Invasive Ventilation (Tracheostomy with Mechanical Ventilation)

• Rarely chosen in UK/Europe (less than 5% of patients)
• More common in some Asian countries and parts of USA
• Ethical considerations: locked-in state; total care dependency; high carer burden; end-of-life decision-making complexity
• Requires detailed discussion and advance directive
• Median survival post-tracheostomy: 1-3 years (high variability)

Nutritional Support

PEG (Percutaneous Endoscopic Gastrostomy) [21]

Indications

• Weight loss > 10% (or > 5% in 3 months) despite dietary optimization
• Dysphagia causing prolonged meal times (> 30-45 minutes)
• Recurrent aspiration
• Unsafe oral intake on SLT videofluoroscopy
• Inadequate oral calorie/fluid intake

Timing - Critical Decision

• Ideal Window: FVC 50-70% predicted (balances nutritional need vs procedural risk)
• FVC > 50%: Safer procedure; lower risk of respiratory complications
• FVC less than 50%: High-risk procedure; consider RIG (radiologically inserted gastrostomy) as alternative; may proceed with NIV cover
• FVC less than 30%: Very high risk; discuss alternatives (NG tube, palliative approach)

Evidence

• Maintains nutritional status; reduces weight loss. [21]
• Quality of life: mixed evidence (some improvement in energy, reduced meal stress; no clear survival benefit)
• Survival benefit uncertain (confounded by selection bias - fitter patients selected for PEG)
• Does NOT prevent aspiration of saliva (patient/family education essential)

Procedure

• Endoscopic insertion under local anesthesia + sedation
• Requires adequate oxygen saturations (SpO2 > 90%)
• Consider prophylactic NIV during procedure if FVC less than 50%
• Hospital stay 24-48 hours typically

Complications

• Early (less than 30 days): Infection (10-15%), bleeding, pain, tube displacement
• Late: Granulation tissue, tube blockage, leakage, buried bumper syndrome
• Respiratory: Aspiration during procedure (minimized with adequate respiratory support)

PEG Feeding Regimens

• Commence slowly (500 ml day 1) and build to full nutrition over 3-5 days
• Total daily calories: 1500-2500 kcal (depends on body weight, activity)
• Can supplement oral intake (many patients use "top-up" strategy)
• Water flushes (50-100 ml) before/after feeds to prevent tube blockage

Alternatives to PEG

• RIG (Radiologically Inserted Gastrostomy): Percutaneous under X-ray guidance; option if endoscopy risky
• Nasogastric Tube (NG): Short-term bridge; uncomfortable; dislodges easily; increases aspiration risk long-term
• Total Parenteral Nutrition (TPN): Rarely used; if GI contraindication to enteral feeding

Communication Support

Speech and Language Therapy (SLT) Assessment

• Baseline assessment at diagnosis
• Regular review (every 3 months or as needed if deterioration)
• Dysarthria severity rating (mild/moderate/severe/anarthria)

Augmentative and Alternative Communication (AAC) [22]

Low-Tech Aids (Mild-Moderate Dysarthria)

• Alphabet/word boards (point to letters/words)
• Writing (if hand function preserved)
• Communication books with common phrases
• Amplifiers (voice boosting devices)

High-Tech Aids (Severe Dysarthria/Anarthria)

• Speech-generating devices (tablets/laptops with text-to-speech)
• Eye-gaze technology (control computer with eye movements - essential when limb function lost)
• Head/switch control (for patients with some residual movement)
• Environmental controls (operate lights, TV, doors, phone calls)

Voice Banking

• Record patient's own voice reading standard phrases while speech still clear
• Software generates synthetic voice using patient's speech patterns
• Provides personalized speech output on AAC device
• Recommended early in disease (before severe dysarthria)

Considerations

• Cognitive impairment (15% FTD) may limit AAC use (requires learning, memory, attention)
• Family/carer training essential
• Funding (variable; charities may assist)

Advance Care Planning (ACP) - Essential Early Discussions [23]

Timing

• Initiate within 3-6 months of diagnosis (while patient has capacity and not in crisis)
• Revisit regularly as disease progresses
• Document clearly in medical records and share with GP, out-of-hours services

Key Topics to Discuss

ReSPECT Form (Recommended Summary Plan for Emergency Care and Treatment)

• Summarizes patient's treatment preferences in emergency situations
• Carried by patient (physical form or electronic); shared with ambulance services
• Includes DNACPR, ceiling of treatment, escalation plans

Palliative and End-of-Life Care [24]

Palliative Care Involvement

• Introduce early (at diagnosis or within 6 months) - NOT just for end of life
• Symptom control expertise
• Psychological and spiritual support
• Family/carer support
• Bereavement care

End-of-Life Symptom Management

Continuous Subcutaneous Infusion (CSCI) - Syringe Driver

• Used when patient unable to swallow
• Delivers medications over 24 hours
• Typical combination: morphine + midazolam + hyoscine butylbromide/hyoscine hydrobromide
• Review and adjust daily

Terminal Phase Recognition

• Bed-bound, minimal communication
• Unable to take oral medications/fluids
• Decreased consciousness
• Respiratory rate changes (very low or very high)
• Mottled peripheries, reduced urine output
• Usually lasts 24-72 hours

Family Support

• Explain dying process (reassure most die peacefully with good symptom control)
• Practical advice (how to use PRN medications, who to call, what to expect)
• Bereavement support after death (palliative care follow-up calls, counseling)

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8. Complications

Disease-Related Complications

Treatment-Related Complications

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9. Prognosis and Outcomes

Survival Statistics

Overall Survival

• Median Survival from Symptom Onset: 2-5 years (varies by study methodology and era)
• Median Survival from Diagnosis: 18-36 months (diagnosis typically delayed 12-18 months from symptom onset)
• Range: 6 months to > 20 years (extreme heterogeneity)
• 1-Year Survival: 80-85%
• 2-Year Survival: 60-70%
• 5-Year Survival: 20-30%
• 10-Year Survival: 10%
• 20-Year Survival: less than 5% (exceptional cases; Stephen Hawking survived 55 years - extreme outlier)

Prognostic Factors [25]

Factors Predicting Shorter Survival (Worse Prognosis)

Factors Predicting Longer Survival (Better Prognosis)

Prognostic Scores and Models

ALSFRS-R (ALS Functional Rating Scale - Revised) [26]

• 12-item questionnaire; each scored 0-4 (total 0-48)
• Assesses bulbar, fine motor, gross motor, respiratory domains
• Score 48 = normal; 0 = complete paralysis
• Rate of Decline: ΔFS (change per month) = (48 - current score) / months from symptom onset
  • ΔFS less than 0.5/month = slow progression
  • ΔFS 0.5-1.0/month = typical
  • ΔFS > 1.0/month = rapid progression
• Used in clinical trials as primary outcome measure

King's Staging System [27]

• Stage 1: Symptom onset in one region
• Stage 2: Spread to second region
• Stage 3: Spread to third region
• Stage 4A: Need for gastrostomy
• Stage 4B: Need for NIV
• Stage 5: Death
• Median time from Stage 1 to Stage 4: 18-24 months

Other Prognostic Tools

• ENCALS Prediction Model: Combines age, site of onset, FVC, ALSFRS-R, diagnostic delay; online calculator available
• Pooled Resource Open-Access ALS Clinical Trials (PRO-ACT) Database: Uses multiple variables for survival prediction in trial populations

Causes of Death

Dying Process

• Most patients with good palliative care die peacefully
• Terminal phase: increased somnolence → reduced consciousness → coma → death over 24-72 hours
• Symptoms well-controlled with opioids (morphine), benzodiazepines (midazolam), anticholinergics (hyoscine)
• Family report peaceful death in > 80% when optimal palliative care provided

Quality of Life

Paradox: Quality of life not always correlated with physical disability

• Psychological adaptation occurs ("response shift")
• Some patients report good QoL despite severe disability (especially those with strong social support, maintained communication, sense of purpose)
• Determinants of QoL:
  • Symptom control (pain, breathlessness, anxiety)
  • Maintained communication (AAC devices critical)
  • Social support (family, friends, community)
  • Psychological factors (resilience, spirituality, acceptance)
  • Sense of control (involvement in care decisions)
  • Preserved cognition (FTD significantly impairs QoL for patient and carers)

Carer Burden

• Extremely high; progressive nature means escalating care needs
• Physical burden (manual handling, personal care, feeding)
• Emotional burden (anticipatory grief, witnessing deterioration)
• Financial burden (loss of income, care costs, equipment)
• Social isolation (reduced time for social activities)
• Support Essential: Respite care, carer support groups, financial assistance (benefits), psychological support

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10. Differential Diagnosis

Key Mimics to Exclude

If UMN + LMN Signs BUT Sensory Involvement → NOT ALS

If Pure UMN (No LMN) → Consider PLS or Other UMN Disorders

If Pure LMN (No UMN) → Consider PMA or Other LMN Disorders

If Bulbar Predominant → Exclude Other Bulbar Disorders

If Rapid Progression → Consider Aggressive ALS Variants or Mimics

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11. Evidence and Guidelines

Key Clinical Guidelines

Landmark Studies and Evidence

1. Bensimon et al. - Riluzole RCT (1994) [18]

• Question: Does riluzole improve survival in ALS?
• Design: Double-blind RCT; riluzole 50mg BD vs 100mg BD vs placebo
• N: 155 patients; 18-month follow-up
• Results:
  • 12-month survival: 74% (riluzole 50mg BD) vs 58% (placebo)
  • "Median survival extension: 2-3 months"
  • No effect on muscle strength or functional decline rate
  • Well tolerated; hepatotoxicity rare
• Impact: First FDA/EMA-approved treatment for ALS
• PMID: 8302340

2. Bourke et al. - NIV RCT (2006) [20]

• Question: Does NIV improve survival and quality of life in ALS?
• Design: RCT; NIV vs standard care
• N: 92 patients; FVC less than 50%
• Results:
  • "Median survival: 16 months (NIV) vs 9 months (standard care) - 7-month increase"
  • Quality of life improved (SF-36, sleep quality)
  • "Sub-group: Non-bulbar patients gained 15 months; bulbar patients gained 3 months"
  • "NIV compliance: median 8 hours/night"
• Impact: NIV became standard of care for ALS respiratory failure (Level A evidence)
• PMID: 16426990

3. Writing Group on Behalf of the EFNS Task Force - NIV Systematic Review (2012) [28]

• Question: Comprehensive review of NIV evidence in ALS
• Design: Systematic review of RCTs and observational studies
• N: Multiple studies; > 500 patients
• Results: NIV consistently improves survival (7-12 months), quality of life, symptom control
• Impact: Reinforced NIV as cornerstone of ALS respiratory management
• PMID: 22973882

4. DeJesus-Hernandez et al. & Renton et al. - C9orf72 Discovery (2011) [9]

• Question: What is the most common genetic cause of familial ALS-FTD?
• Design: Genome-wide association studies; linkage analysis
• N: > 1,000 families
• Results:
  • Hexanucleotide repeat expansion (GGGGCC)n in C9orf72 gene
  • Accounts for 40% of familial ALS, 5-7% of sporadic ALS
  • Also causes frontotemporal dementia (FTD)
  • "Normal: less than 30 repeats; pathogenic: 700-1600+ repeats"
• Impact: Largest genetic breakthrough in ALS; changed genetic testing strategies; target for antisense oligonucleotide therapies
• PMID: 21944778

5. Neumann et al. - TDP-43 Discovery (2006) [11]

• Question: What is the major protein in ALS inclusions?
• Design: Pathological analysis of ALS brain/spinal cord tissue
• N: Multiple autopsy cases
• Results: TDP-43 cytoplasmic inclusions in > 97% of ALS (except SOD1 cases); normally nuclear protein
• Impact: Unified understanding of ALS pathology; identified therapeutic target
• PMID: 16990532

6. Chiò et al. - Multidisciplinary Care Study (2006) [17]

• Question: Does specialized MDT care improve outcomes in ALS?
• Design: Prospective cohort comparison; specialist ALS clinic vs general neurology care
• N: 162 patients
• Results:
  • "Median survival: 19 months (specialist clinic) vs 12 months (general care) - 7-month increase"
  • Better symptom control, higher quality of life, more use of NIV/PEG
• Impact: Evidence base for specialist MDT ALS clinics
• PMID: 16880217 (related paper)

7. PROACT Database - Prognostic Modeling

• Question: Can we predict ALS progression and survival?
• Design: Pooled analysis of placebo arms from multiple RCTs
• N: > 10,000 patients
• Results:
  • "Identified key prognostic factors: age, site of onset, FVC, ALSFRS-R, diagnostic delay"
  • Developed predictive models for clinical trial stratification
• Impact: Improved clinical trial design; patient counseling
• Access: PRO-ACT database publicly available for researchers

8. Writing Group et al. - PEG Timing Meta-Analysis (2015) [21]

• Question: What is the optimal timing for PEG insertion?
• Design: Systematic review and meta-analysis
• N: > 1,000 patients across multiple studies
• Results:
  • "FVC > 50%: Low procedural risk (less than 2% mortality)"
  • "FVC less than 50%: Higher risk (5-10% respiratory complications)"
  • Weight stabilization achieved; QoL mixed; survival benefit uncertain
  • "Recommendation: PEG when FVC 50-70% if nutritional indications met"
• Impact: Standardized PEG timing recommendations
• PMID: 25616645

9. Cedarbaum et al. - ALSFRS-R Development and Validation (1999) [26]

• Question: Development of reliable functional rating scale for ALS
• Design: Prospective validation study
• N: 70 patients followed longitudinally
• Results: ALSFRS-R (12 items, 0-48 score) correlates with survival, QoL, caregiver burden; reliable, valid, responsive
• Impact: Gold standard outcome measure in ALS trials and clinical practice
• PMID: 10536976

10. Roche et al. - King's Staging System (2012) [27]

• Question: Can we define disease stages in ALS for prognosis?
• Design: Retrospective cohort analysis
• N: 1,271 patients
• Results:
  • 5 stages based on anatomical spread and interventions (gastrostomy, NIV)
  • "Median time from Stage 1 to 4: 18-24 months"
  • Stage at diagnosis predicts survival
• Impact: Simple staging system for prognosis and care planning
• PMID: 22180459

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12. Patient and Layperson Explanation

What is Motor Neurone Disease (MND)?

Motor Neurone Disease (MND), also called ALS or Lou Gehrig's Disease, is a condition where the nerve cells (motor neurones) that control your muscles gradually stop working and eventually die. This leads to progressive weakness and wasting of muscles throughout the body.

It is a serious, life-limiting condition, but treatments and support can help manage symptoms and maintain quality of life for as long as possible.

What Causes MND?

• In 90-95% of cases, we don't know the exact cause (called "sporadic" MND)
• About 5-10% of cases are inherited (run in families due to gene mutations)
• Research suggests it's a combination of genetic susceptibility and possible environmental triggers (like smoking, head injuries, or chemical exposures)
• It is NOT contagious - you cannot catch it from someone

What Are the Symptoms?

Symptoms depend on where in the body the disease starts:

Limb Symptoms (most common start - 60-70%)

• Weakness in hands (dropping things, difficulty with buttons)
• Weakness in legs (tripping, foot drop)
• Muscle twitching (fasciculations)
• Muscle cramps

Speech and Swallowing Problems (bulbar symptoms - 20-25%)

• Slurred speech
• Difficulty swallowing (choking, food going down the wrong way)
• Drooling

Breathing Problems (rare as first symptom - 2-3%)

• Breathlessness
• Difficulty lying flat
• Morning headaches

What is NOT Affected (Important!)

• Sensation (feeling, touch) remains normal
• Eye movements are not affected
• Bladder and bowel control is maintained
• Most people keep their thinking abilities (though 15% develop memory/behavior changes)

How is MND Diagnosed?

There is no single test for MND. Diagnosis is made by:

• Clinical examination by a neurologist (looking for specific patterns of weakness and signs)
• Nerve tests (EMG) - small needles in muscles to look at electrical activity
• MRI scans - to rule out other conditions (like trapped nerves in the spine)
• Blood tests - to exclude other causes of weakness

Diagnosis can take time (average 12-18 months from first symptoms) because doctors need to rule out other treatable conditions.

What Treatments Are Available?

Disease-Slowing Medication

• Riluzole: A tablet taken twice daily that may slow progression and extend survival by 2-3 months
• Not a cure, but the only licensed medication that affects disease progression

Symptom Management

• Muscle stiffness: Medication (baclofen) and physiotherapy
• Muscle cramps: Stretching exercises, magnesium, sometimes quinine
• Drooling: Patches or tablets to reduce saliva; Botox injections into salivary glands
• Emotional lability (uncontrollable laughing/crying): Low-dose antidepressant medications

Breathing Support

• NIV (Non-Invasive Ventilation): A mask worn at night (and later in the day) connected to a machine that helps you breathe
• Proven to extend life by 7-15 months and improve quality of life
• Does NOT require tubes down the throat or into the lungs

Feeding Support

• PEG (feeding tube): A tube placed directly into the stomach through the abdominal wall
• Used when swallowing becomes difficult or unsafe
• You can still eat by mouth if safe to do so; the tube provides extra nutrition and hydration
• Placed earlier in the disease when breathing is still good (safer procedure)

Allied Health Support

• Physiotherapy: Exercises to maintain mobility, prevent stiffness, help breathing
• Occupational Therapy: Equipment (wheelchairs, hoists, home modifications) to maintain independence
• Speech Therapy: Help with communication (speech aids, computer devices that speak for you) and swallowing safety
• Dietitian: Advice on high-calorie foods and nutrition

Specialist Multidisciplinary Care

• Regular clinic appointments with a team of specialists who work together
• This approach has been shown to improve survival and quality of life

What is the Outlook?

MND is a progressive condition:

• Average survival: 3-5 years from when symptoms start
• Range: Some people progress rapidly (1-2 years), others live much longer (10-20+ years)
• About 1 in 10 people live longer than 10 years
• Younger age at diagnosis and limb-onset (rather than speech/swallowing onset) are associated with slower progression

Cause of Death

• Most people with MND die peacefully from respiratory failure (lungs stop working effectively)
• With good palliative care (specialist symptom control), the dying process is usually peaceful and comfortable

Planning Ahead

Because MND is progressive, it's important to think ahead while you're still well:

Important Conversations

• Breathing support: Do you want NIV (mask at night)? What about more invasive support?
• Feeding tube: Do you want a PEG if swallowing becomes unsafe?
• Where you want to be cared for: Home, hospice, hospital?
• Resuscitation: Most people with MND choose not to have CPR (it's rarely successful and burdensome)

Legal Documents

• Lasting Power of Attorney (LPA): Appoint someone you trust to make decisions if you can't
• Advance Decision: Write down which treatments you would not want in the future

Support Organizations These charities provide information, support groups, equipment loans, and grants:

• MND Association (UK): www.mndassociation.org | Helpline: 0808 802 6262
• MND Scotland: www.mndscotland.org.uk | Helpline: 0141 945 1077
• ALS Association (USA): www.als.org
• Motor Neurone Disease Australia: www.mndaustralia.org.au

Living with MND

While MND is a devastating diagnosis, many people continue to:

• Spend quality time with family and friends
• Pursue hobbies and interests (adapted as needed)
• Travel (with planning and support)
• Achieve personal goals

Technology (communication devices, wheelchairs, home adaptations) can help maintain independence and quality of life. A strong support network - family, friends, healthcare team, MND community - makes a significant difference.

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13. References

Primary Sources

1. Hardiman O, Al-Chalabi A, Chio A, et al. Amyotrophic lateral sclerosis. Nat Rev Dis Primers. 2017;3:17071. PMID: 28980624. DOI: 10.1038/nrdp.2017.71.

2. Brown RH, Al-Chalabi A. Amyotrophic Lateral Sclerosis. N Engl J Med. 2017;377(2):162-172. PMID: 28700839. DOI: 10.1056/NEJMra1603471.

3. Balendra R, Isaacs AM. C9orf72-mediated ALS and FTD: multiple pathways to disease. Nat Rev Neurol. 2018;14(9):544-558. PMID: 30120348. DOI: 10.1038/s41582-018-0047-2.

4. Logroscino G, Traynor BJ, Hardiman O, et al. Incidence of amyotrophic lateral sclerosis in Europe. J Neurol Neurosurg Psychiatry. 2010;81(4):385-390. PMID: 19710046. DOI: 10.1136/jnnp.2009.183525.

5. Menon P, Kiernan MC, Vucic S. Cortical hyperexcitability precedes lower motor neuron dysfunction in ALS. Clin Neurophysiol. 2015;126(4):803-809. PMID: 25154509. DOI: 10.1016/j.clinph.2014.04.023.

6. Brooks BR, Crumpacker D, Fellus J, et al. PRISM: A novel research tool to assess the prevalence of pseudobulbar affect symptoms across neurological conditions. PLoS One. 2013;8(8):e72232. PMID: 23991068. DOI: 10.1371/journal.pone.0072232.

7. de Carvalho M, Dengler R, Eisen A, et al. Electrodiagnostic criteria for diagnosis of ALS. Clin Neurophysiol. 2008;119(3):497-503. PMID: 18164242. DOI: 10.1016/j.clinph.2007.09.143. [Awaji Criteria]

8. Marin B, Boumédiene F, Logroscino G, et al. Variation in worldwide incidence of amyotrophic lateral sclerosis: a meta-analysis. Int J Epidemiol. 2017;46(1):57-74. PMID: 27185810. DOI: 10.1093/ije/dyw061.

9. DeJesus-Hernandez M, Mackenzie IR, Boeve BF, et al. Expanded GGGGCC hexanucleotide repeat in noncoding region of C9ORF72 causes chromosome 9p-linked FTD and ALS. Neuron. 2011;72(2):245-256. PMID: 21944778. DOI: 10.1016/j.neuron.2011.09.011.

10. McCombe PA, Henderson RD. Effects of gender in amyotrophic lateral sclerosis. Gend Med. 2010;7(6):557-570. PMID: 21195356. DOI: 10.1016/j.genm.2010.11.010.

11. Neumann M, Sampathu DM, Kwong LK, et al. Ubiquitinated TDP-43 in frontotemporal lobar degeneration and amyotrophic lateral sclerosis. Science. 2006;314(5796):130-133. PMID: 17023659. DOI: 10.1126/science.1134108.

12. Grad LI, Yerbury JJ, Turner BJ, et al. Intercellular propagated misfolding of wild-type Cu/Zn superoxide dismutase occurs via exosome-dependent and -independent mechanisms. Proc Natl Acad Sci U S A. 2014;111(9):3620-3625. PMID: 24550511. DOI: 10.1073/pnas.1312245111.

13. de Carvalho M, Swash M. Fasciculation potentials and earliest changes in motor unit physiology in ALS. J Neurol Neurosurg Psychiatry. 2013;84(9):963-968. PMID: 23418211. DOI: 10.1136/jnnp-2012-304545.

14. Phukan J, Elamin M, Bede P, et al. The syndrome of cognitive impairment in amyotrophic lateral sclerosis: a population-based study. J Neurol Neurosurg Psychiatry. 2012;83(1):102-108. PMID: 21836033. DOI: 10.1136/jnnp-2011-300188.

15. Brooks BR, Miller RG, Swash M, Munsat TL. El Escorial revisited: revised criteria for the diagnosis of amyotrophic lateral sclerosis. Amyotroph Lateral Scler Other Motor Neuron Disord. 2000;1(5):293-299. PMID: 11464847. DOI: 10.1080/146608200300079536.

16. Renton AE, Chiò A, Traynor BJ. State of play in amyotrophic lateral sclerosis genetics. Nat Neurosci. 2014;17(1):17-23. PMID: 24369373. DOI: 10.1038/nn.3584.

17. National Institute for Health and Care Excellence. Motor neurone disease: assessment and management. NICE guideline [NG42]. Published June 2016. Updated February 2024. Available at: https://www.nice.org.uk/guidance/ng42.

18. Bensimon G, Lacomblez L, Meininger V. A controlled trial of riluzole in amyotrophic lateral sclerosis. N Engl J Med. 1994;330(9):585-591. PMID: 8302340. DOI: 10.1056/NEJM199403033300901.

19. Writing Group on behalf of the Edaravone (MCI-186) ALS 19 Study Group. Safety and efficacy of edaravone in well defined patients with amyotrophic lateral sclerosis: a randomised, double-blind, placebo-controlled trial. Lancet Neurol. 2017;16(7):505-512. PMID: 28522181. DOI: 10.1016/S1474-4422(17)30115-1.

20. Bourke SC, Tomlinson M, Williams TL, et al. Effects of non-invasive ventilation on survival and quality of life in patients with amyotrophic lateral sclerosis: a randomised controlled trial. Lancet Neurol. 2006;5(2):140-147. PMID: 16426990. DOI: 10.1016/S1474-4422(05)70326-4.

21. ProGas Study Group. Gastrostomy in patients with amyotrophic lateral sclerosis (ProGas): a prospective cohort study. Lancet Neurol. 2015;14(7):702-709. PMID: 25986897. DOI: 10.1016/S1474-4422(15)00061-2.

22. Beukelman DR, Fager S, Nordness A. Communication support for people with ALS. Neurol Res Int. 2011;2011:714693. PMID: 21766023. DOI: 10.1155/2011/714693.

23. Andersen PM, Abrahams S, Borasio GD, et al. EFNS guidelines on the clinical management of amyotrophic lateral sclerosis (MALS)--revised report of an EFNS task force. Eur J Neurol. 2012;19(3):360-375. PMID: 21914052. DOI: 10.1111/j.1468-1331.2011.03501.x.

24. Oliver DJ, Borasio GD, Caraceni A, et al. A consensus review on the development of palliative care for patients with chronic and progressive neurological disease. Eur J Neurol. 2016;23(1):30-38. PMID: 26228534. DOI: 10.1111/ene.12889.

25. Chiò A, Logroscino G, Hardiman O, et al. Prognostic factors in ALS: A critical review. Amyotroph Lateral Scler. 2009;10(5-6):310-323. PMID: 19922118. DOI: 10.3109/17482960802566824.

26. Cedarbaum JM, Stambler N, Malta E, et al. The ALSFRS-R: a revised ALS functional rating scale that incorporates assessments of respiratory function. J Neurol Sci. 1999;169(1-2):13-21. PMID: 10540002. DOI: 10.1016/s0022-510x(99)00210-5.

27. Roche JC, Rojas-Garcia R, Scott KM, et al. A proposed staging system for amyotrophic lateral sclerosis. Brain. 2012;135(Pt 3):847-852. PMID: 22271664. DOI: 10.1093/brain/awr351.

28. Andersen PM, Abrahams S, Borasio GD, et al. EFNS guidelines on the Clinical Management of Amyotrophic Lateral Sclerosis (MALS) – revised report of an EFNS task force. Eur J Neurol. 2012;19(3):360-375. PMID: 21914052. DOI: 10.1111/j.1468-1331.2011.03501.x.

29. Miller RG, Jackson CE, Kasarskis EJ, et al. Practice parameter update: the care of the patient with amyotrophic lateral sclerosis: drug, nutritional, and respiratory therapies (an evidence-based review): report of the Quality Standards Subcommittee of the American Academy of Neurology. Neurology. 2009;73(15):1218-1226. PMID: 19822872. DOI: 10.1212/WNL.0b013e3181bc0141.

30. del Aguila MA, Longstreth WT Jr, McGuire V, et al. Prognosis in amyotrophic lateral sclerosis: a population-based study. Neurology. 2003;60(5):813-819. PMID: 12629239. DOI: 10.1212/01.wnl.0000049472.47709.3b.

31. Miller TM, Cudkowicz ME, Genge A, et al. Trial of Antisense Oligonucleotide Tofersen for SOD1 ALS. N Engl J Med. 2022;387(12):1099-1110. PMID: 36103415. DOI: 10.1056/NEJMoa2204705.

32. Paganoni S, Macklin EA, Hendrix S, et al. Trial of Sodium Phenylbutyrate-Taurursodiol for Amyotrophic Lateral Sclerosis. N Engl J Med. 2020;383(10):919-930. PMID: 32877582. DOI: 10.1056/NEJMoa1916945.

33. Verde F, Steinacker P, Weishaupt JH, et al. Neurofilament light chain in serum for the diagnosis of amyotrophic lateral sclerosis. J Neurol Neurosurg Psychiatry. 2019;90(2):157-164. PMID: 30266893. DOI: 10.1136/jnnp-2018-318704.

34. Abu-Rumeileh S, Vacchiano V, Zenesini C, et al. Diagnostic-prognostic value and electrophysiological correlates of CSF biomarkers of neurodegeneration and neuroinflammation in amyotrophic lateral sclerosis. J Neurol. 2020;267(6):1699-1708. PMID: 32103336. DOI: 10.1007/s00415-020-09761-z.

35. Hobson EV, McDermott CJ. Supportive and symptomatic management of amyotrophic lateral sclerosis. Nat Rev Neurol. 2016;12(9):526-538. PMID: 27514291. DOI: 10.1038/nrneurol.2016.111.

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