Amyotrophic Lateral Sclerosis (ALS)

Populations and Risk Factors

Onset most common between ages 40 and 70; mean age of onset approximately 55 years
Males affected slightly more often than females (approximately 1.5:1), though the sex difference narrows with age
90–95% of cases are sporadic (no family history); 5–10% are familial with autosomal dominant inheritance (SOD1 gene mutation most commonly identified)
Military veterans have approximately twice the risk of the general population — mechanism unknown but possibly related to environmental exposures, physical trauma, or strenuous exertion
Smoking is a confirmed risk factor, particularly in women
No consistently identified occupational risk factors, though associations with heavy manual labor and professional athletics have been reported
Prior head trauma and high-intensity physical activity have been suggested as risk factors but remain inconclusive

Causes and Pathophysiology

Motor Neuron Degeneration — The Dual-Pathway Lesion

Corticospinal tract (UMN) degeneration: Motor neurons originating in the primary motor cortex and descending through the lateral corticospinal tracts undergo progressive degeneration. Loss of these neurons removes inhibitory modulation of spinal cord reflexes, producing spasticity (velocity-dependent hypertonia), hyperreflexia, clonus, and a positive Babinski sign. The "lateral sclerosis" in the name refers to the scarring (gliosis) of the lateral columns of the spinal cord where these tracts run.
Anterior horn cell (LMN) degeneration: Motor neurons in the anterior horn of the spinal cord and in brainstem motor nuclei (for cranial nerves) degenerate and die. Loss of these neurons disconnects the muscle fibers they innervate. Denervated muscle fibers atrophy, lose tone, and cannot contract voluntarily. The "amyotrophic" in the name refers to this muscle wasting.
Why both pathways simultaneously: This is the defining feature of ALS. No other common neurological condition produces both UMN and LMN signs in the same body region at the same time. MS produces UMN signs only. Peripheral neuropathies and radiculopathies produce LMN signs only. The El Escorial diagnostic criteria require evidence of both UMN and LMN involvement in at least two body regions (bulbar, cervical, thoracic, lumbosacral) with progressive spread.

Cellular Mechanisms

Motor neuron replacement by fibrous astrocytes: As motor neurons die, they are replaced by reactive astrocytic glial tissue rather than new neurons. This gliosis forms the scar tissue visible on histopathology and contributes to the hardening of the lateral columns.
Glutamate excitotoxicity: Excessive glutamate accumulation at the synaptic cleft overstimulates motor neurons through NMDA and AMPA receptors, leading to calcium influx and neuronal death. This is the primary mechanism targeted by riluzole — the first drug approved for ALS — which reduces presynaptic glutamate release and extends survival by approximately 2 to 3 months.
Oxidative stress: Free radical damage to motor neurons, particularly in patients with SOD1 (superoxide dismutase 1) mutations. The SOD1 enzyme normally neutralizes superoxide radicals; mutations produce a toxic gain of function rather than simple loss of antioxidant protection.
Mitochondrial dysfunction: Impaired mitochondrial function in motor neurons reduces ATP production and increases susceptibility to oxidative damage, compounding the excitotoxic cascade.
Protein aggregation: Abnormal protein clumps (ubiquitinated inclusions, TDP-43 aggregates) accumulate in affected motor neurons, disrupting intracellular transport and contributing to neuronal death.

Why Fasciculations Occur

When a motor neuron is dying but not yet dead, the denervated motor unit becomes electrically unstable. The remaining viable portions of the axon fire spontaneously, producing involuntary, visible twitching of the muscle fibers in that motor unit — a fasciculation.
Fasciculations are therefore a sign of active denervation — they indicate motor neuron death in progress. They differ from benign fasciculations (which occur in healthy individuals) by their association with progressive weakness and atrophy in the same muscle group.
Clinically, fasciculations are visible at rest and palpable as brief, irregular twitches beneath the skin. They occur in muscles that have not yet fully atrophied but whose motor neurons are actively degenerating.

Selective Vulnerability

ALS selectively targets voluntary motor neurons. Sensory neurons, autonomic neurons, and higher cognitive centers are spared. This means sensation is fully intact (patients feel everything), cognition is preserved in approximately 50% of cases (the remainder may develop frontotemporal cognitive changes, but frank dementia is uncommon), and autonomic functions (heart rate, blood pressure, gastrointestinal motility) are maintained.
Oculomotor neurons and sacral motor neurons controlling the external urethral and anal sphincters are characteristically spared until very late in the disease, distinguishing ALS from MS and spinal cord injury.
Respiratory failure is the primary cause of death because the diaphragm (innervated by C3–C5 via the phrenic nerve) and intercostal muscles (innervated by thoracic anterior horn cells) are voluntary muscles subject to the same degeneration. Progressive weakness of these muscles leads to hypoventilation, aspiration, and ultimately respiratory failure.

Signs and Symptoms

Spinal-Onset ALS (~70% of cases)

Asymmetric limb weakness is the presenting symptom — typically begins in one hand (difficulty with fine motor tasks: buttons, keys, writing) or one foot (foot drop, tripping)
Mixed UMN and LMN signs in the affected limb: weakness and visible atrophy (LMN) alongside spasticity, hyperreflexia, and stiffness (UMN)
Fasciculations visible in affected and adjacent muscles — patients often describe "muscle twitching" as an early symptom
Progressive spread to the contralateral limb, then to other body regions (arms to legs or vice versa)
Deep tendon reflexes are paradoxically brisk (hyperreflexia) even in a limb that is visibly weak and atrophied — this UMN + LMN combination is the clinical hallmark
Muscle cramps, particularly in the calves and hands, often precede detectable weakness
Progressive difficulty with walking, transfers, and eventually all voluntary movement

Bulbar-Onset ALS (~30% of cases)

Presents with speech and swallowing difficulties rather than limb weakness
Dysarthria: slurred, nasal, or strained speech from weakness of the tongue, lips, palate, and laryngeal muscles
Dysphagia: difficulty swallowing liquids initially (due to loss of coordinated pharyngeal contraction), progressing to solids; choking episodes; aspiration risk
Emotional incontinence (pseudobulbar affect): involuntary episodes of laughing or crying disproportionate to the emotional stimulus — caused by loss of UMN inhibitory control over brainstem emotional circuitry; not a psychiatric condition
Tongue fasciculations and atrophy: visible on examination; the tongue may appear furrowed and reduced in bulk
Limb symptoms eventually develop in all cases — bulbar onset does not remain isolated
Generally associated with a shorter survival than spinal onset

Progression Timeline

Early (0–12 months from diagnosis): Focal weakness in one region; fasciculations; mild functional limitation; may still be ambulatory and independent
Middle (1–3 years): Weakness spreads to multiple limbs; significant atrophy visible; assistive devices required (wheelchair, walker); speech declining; swallowing compromised; may require PEG tube for nutrition
Late (2–5+ years): Quadriparesis or quadriplegia; respiratory support required (BiPAP, ventilator); near-total loss of voluntary movement; communication may require augmentative devices; death from respiratory failure without ventilatory support

Assessment Profile

Subjective Presentation

Chief complaint: Typically presents with progressive weakness in one limb — "My hand doesn't work right anymore," "I keep tripping over my foot," or "My speech is getting slurry"; history of progressive worsening over months without remission; may report muscle twitching (fasciculations) as an early concern
Pain quality: ALS itself is not a pain-generating disease — motor neurons do not produce nociceptive input. Pain arises from secondary sources: muscle cramps and spasms (LMN irritability), joint pain from immobility, postural pain from compensatory patterns, and painful spasticity-related contractures; certain stimuli or sudden movements can trigger painful spasms
Onset: Insidious onset over months; no single precipitating event; progressive without remission (distinguishes from MS which remits); patients typically seek care months after symptom onset
Aggravating factors: Physical exertion worsens fatigue and may transiently worsen weakness; cold exacerbates spasticity and cramping; prolonged positioning worsens contracture pain; emotional stress may trigger pseudobulbar episodes
Easing factors: Rest reduces fatigue but does not restore strength; gentle passive movement may temporarily reduce spasticity; warm applications may ease cramps and spastic pain (unlike MS, heat does not worsen neurological function in ALS); positioning adjustments relieve postural pain
Red flags: Rapidly progressive dysphagia with aspiration → urgent medical review for nutritional and respiratory support; new-onset respiratory distress (dyspnea at rest, orthopnea, morning headaches from CO2 retention) → emergency respiratory assessment; do not treat without confirming current respiratory status

Observation

Local inspection: Visible muscle atrophy — may be asymmetric, most prominent in intrinsic hand muscles (thenar and hypothenar wasting) or anterior compartment of the leg; fasciculations visible at rest in multiple muscle groups (arms, legs, trunk, tongue); patient may arrive with assistive devices (wheelchair, walker, AFO, head support), communication devices, or respiratory support equipment (BiPAP, portable ventilator)
Posture: Depends on disease stage — early: subtle lean or shoulder drop on the weaker side; mid-stage: slumped posture from trunk weakness, cervical flexion from head control loss; late-stage: fully supported in wheelchair with head rest and trunk support; kyphotic posture from progressive axial weakness
Gait: If ambulatory: mixed spastic-ataxic gait from combined UMN stiffness and LMN weakness; steppage gait from foot drop; wide-based for balance compensation; gait progressively deteriorates and is eventually lost entirely

Palpation

Tone: Mixed UMN and LMN findings in the same patient — the palpation hallmark of ALS. Spastic hypertonia coexists with flaccid atrophy. In a given limb, proximal muscles may be spastic while distal muscles are atrophied and hypotonic, or vice versa. Contractures develop in chronically spastic muscles (hip flexors, knee flexors, plantarflexors, elbow flexors, wrist flexors) as active movement is lost.
Tenderness: Spastic muscles are tender from sustained contraction and ischemia. Cramped muscles are acutely painful during the cramp. Trigger points develop in chronically hypertonic muscles. Bony prominences become tender from prolonged positioning in immobile patients. Sensation is fully intact — patient feedback on pressure is reliable.
Temperature: Normal skin temperature in most cases; extremities may be cooler from reduced activity and dependent positioning; no inflammation-related warmth; warm applications are not neurologically contraindicated (unlike MS — ALS does not involve Uhthoff's phenomenon)
Tissue quality: Atrophied muscles feel soft, thin, and reduced in bulk. Fasciculations are palpable as brief, irregular twitches beneath the skin — small flickers or ripples under the fingers. Spastic muscles feel hypertonic, inelastic, and resistant to passive elongation. Skin may be fragile and poorly nourished in late-stage disease from immobility.

Motion Assessment

AROM: Progressively reduced — weakness limits force production while spasticity limits available range. Pattern is non-dermatomal and non-capsular. Serial decline in MMT grades over weeks to months is characteristic and tracks disease progression. Early disease may show 4/5 in isolated muscles, progressing to 0/5 in late disease.
PROM / end-feel: Spastic muscles show velocity-dependent resistance on PROM — faster stretch meets greater resistance. End-feel is elastic-muscular in early stages, becoming firm-fibrotic as contractures develop. Slow sustained PROM may achieve greater range than AROM. Fully denervated muscles offer no resistance (flaccid end-feel). Contractured joints show a hard end-feel that does not yield to sustained pressure.
Resisted testing: Progressive weakness on MMT is the primary quantitative measure. Weakness is LMN-pattern in distribution — specific muscles, not broad limb weakness. Serial MMT documentation tracks rate of progression. Fasciculations may be visible during testing. Note both strength grade and whether the muscle fatigues rapidly during sustained effort.

Special Test Cluster

ALS is diagnosed medically (EMG/NCS, MRI, El Escorial criteria). The MT special test cluster is oriented toward confirming the mixed UMN + LMN presentation, tracking progression, and screening for complications.

Test	Positive Finding	Purpose
Babinski Sign (CMTO)	Great toe extends (dorsiflexes), other toes fan out when the lateral sole is stroked	Confirm UMN involvement; positive in adults indicates corticospinal tract pathology
Deep tendon reflexes (UE and LE) (CMTO)	Hyperreflexia (3+ to 4+) in a limb that also shows weakness and atrophy — the paradoxical combination confirms mixed UMN + LMN disease	Differentiate ALS (mixed) from pure UMN (MS) or pure LMN (peripheral neuropathy); hyperreflexia in an atrophied limb is highly suggestive of ALS
Fasciculation observation (CMTO)	Visible spontaneous twitching in resting muscles across multiple body regions (not limited to one nerve root or peripheral nerve)	Confirm widespread active denervation (LMN); distribution across multiple myotomes supports ALS over focal nerve lesion
Manual Muscle Testing — serial (CMTO)	Progressive decline in strength grades over weeks to months; non-dermatomal, non-myotomal pattern	Track rate of progression; serial decline without remission is characteristic of ALS; stable or improving strength suggests an alternative diagnosis
Bulbar screen (tongue, speech, swallow) (supplementary)	Tongue fasciculations and atrophy; slurred or nasal speech; wet or gurgling voice quality after swallowing	Screen for bulbar involvement — affects treatment positioning (aspiration risk in prone/supine), communication during treatment, and prognosis

Mixed UMN + LMN — the ALS signature: If DTRs are hyperreflexic (UMN) in a limb that is also weak and atrophied (LMN), this mixed finding is the clinical hallmark of ALS. No single special test confirms ALS — it is the combination of UMN and LMN signs across multiple body regions with progressive spread that defines the disease.

Differential Assessment

Condition	Key Distinguishing Feature
Multiple Sclerosis	UMN signs only (no LMN atrophy, fasciculations, or anterior horn cell involvement); sensory symptoms present (numbness, tingling); relapsing-remitting course; MRI shows demyelinating plaques
Cervical Myelopathy	UMN signs below the lesion, LMN signs at the lesion level only — does not produce widespread LMN involvement across multiple segments; MRI shows cord compression at a specific level
Myasthenia Gravis	Fatigable weakness that worsens with repeated use and improves with rest; no UMN signs (reflexes normal, Babinski negative); positive edrophonium (Tensilon) test; no fasciculations; no atrophy in early disease
Multifocal Motor Neuropathy	Pure LMN — no UMN signs (no spasticity, no hyperreflexia, negative Babinski); responds to immunoglobulin therapy; conduction block on NCS
Kennedy Disease (SBMA)	X-linked — males only; very slow progression (decades); gynecomastia, testicular atrophy; facial fasciculations prominent; no UMN signs

CMTO Exam Relevance

CMTO Appendix category A4 (neurological conditions)
Know that ALS produces both UMN and LMN signs simultaneously — this is the defining feature that distinguishes it from MS (UMN only), peripheral neuropathy (LMN only), and GBS (LMN only)
The mixed presentation means hyperreflexia and positive Babinski (UMN) coexist with atrophy, fasciculations, and weakness (LMN) — exam questions may test whether students recognize this paradox
Understand that ALS is a palliative care condition — there is no cure or significant disease-modifying treatment; MT goals are comfort, contracture prevention, and quality of life
Know the two onset types: spinal (~70%) and bulbar (~30%) and their presenting features
Respiratory failure is the primary cause of death — questions may test awareness of respiratory compromise signs (dyspnea, orthopnea, morning headaches)
Fasciculations represent active denervation — distinguish from benign fasciculation syndrome (no progressive weakness or atrophy)
ALS does NOT involve Uhthoff's phenomenon (no demyelination) — do not confuse with MS heat precautions

Massage Therapy Considerations

Primary therapeutic target: secondary effects of progressive motor neuron loss — spastic tone, contractures, positional discomfort, respiratory muscle tension, and the psychological burden of a terminal diagnosis; MT does not address the underlying neurodegeneration
Palliative care framework: all treatment planning operates within a palliative model; goals shift from functional improvement to comfort maintenance as the disease progresses; the therapeutic relationship and quality of touch become increasingly important as other forms of communication and interaction are lost
Mixed tone principle: spastic muscles require slow, sustained techniques (same as MS) while atrophied muscles require gentle, supportive handling — the same patient may need both approaches in different body regions or even different aspects of the same limb; contractured joints require sustained passive range maintenance, not aggressive stretching
Spasm awareness: certain stimuli — sudden position changes, rapid passive movement, cold application, or unexpected touch — can trigger painful extensor or flexor spasms; all handling must be slow, predictable, and communicated verbally before contact
No resistive exercise: do not perform resisted strengthening or exercise against resistance; motor neurons that are dying cannot be strengthened through exercise, and the metabolic demand accelerates fatigue without benefit; gentle PROM only
Respiratory awareness: as respiratory muscles weaken, prone positioning may be impossible; supine may be difficult due to orthopnea (dyspnea when lying flat); side-lying or semi-reclined positioning is often required; be aware of and accommodate BiPAP masks, portable ventilators, and supplemental oxygen
Heat is NOT contraindicated: unlike MS, ALS does not involve demyelination and there is no Uhthoff's phenomenon; moist heat can be used safely for comfort and to ease spastic tone and cramping
Intact sensation: the patient feels everything normally; client feedback on pressure is reliable and should be actively sought; this is both an advantage (accurate feedback) and a responsibility (the patient experiences all pain and discomfort from their condition)

Treatment Plan Foundation

Clinical Goals

Reduce spastic muscle tone and prevent or slow contracture development in affected limbs
Maintain available passive range of motion in joints at risk of contracture
Provide comfort and reduce pain from spasticity, cramping, and prolonged positioning
Support respiratory function through accessory breathing muscle release and optimal positioning

Position

Side-lying is preferred in most cases — accommodates respiratory equipment, avoids orthopnea, and provides access to trunk and limbs
Semi-reclined (supported upright at 30–45 degrees) for patients who cannot tolerate side-lying or who require continuous respiratory support
Prone is generally contraindicated in moderate-to-advanced disease due to respiratory compromise and difficulty with transfers
Supine may be used for upper extremity and cervical work if the patient tolerates flat positioning — monitor for respiratory distress
Additional bolstering and padding required at all bony prominences (fragile skin from immobility); accommodate head support devices, communication boards, and respiratory equipment within the treatment setup

Session Sequence

General effleurage to accessible trunk and extremities — establish contact slowly and predictably; assess tone distribution (identify which areas are spastic vs. atrophied); note any fasciculations, contractures, or areas of positional pain
Slow, sustained myofascial release to the most spastic muscle groups — typically hip flexors, knee flexors, plantarflexors, and elbow flexors; velocity must remain slow to avoid triggering spasms or the stretch reflex
Gentle sustained compression to trigger points in chronically hypertonic muscles — hold until tissue softens; do not use deep aggressive pressure; target paraspinals, upper trapezius, and forearm flexors as common sites of cramp-related trigger points
Supportive effleurage and gentle petrissage to atrophied muscles — goal is comfort and circulatory support, not tone restoration; very light pressure appropriate; handle wasted tissue gently
Accessory respiratory muscle release — gentle work to intercostals (accessible in side-lying), scalenes, upper trapezius, and sternocleidomastoid to reduce accessory breathing effort [monitor respiratory status throughout — stop if breathing difficulty increases]
Gentle passive range of motion to at-risk joints — slow, sustained movement through available range; focus on joints showing early contracture (ankles into dorsiflexion, knees into extension, elbows into extension, wrists into extension); do not force past available range
Finishing effleurage — light, rhythmic, calming strokes; ensure patient is comfortable, well-positioned, and respiratory support is properly in place before ending

Adjunct Modalities

Hydrotherapy: moist heat (warm towels, hydrocollator packs) applied to spastic muscles before and during treatment to reduce tone and ease cramping — heat is safe in ALS (no Uhthoff's phenomenon); avoid sudden temperature changes that may trigger spasms; warm applications to the trunk and proximal limbs for comfort in late-stage patients
Remedial exercise (on-table): gentle therapist-assisted passive ROM through available range in all affected joints — purpose is contracture prevention and joint nutrition, not strengthening; do NOT perform resistive exercise of any kind; active-assisted ROM only if the patient has sufficient voluntary control and does not fatigue; stop immediately if fatigue is apparent

Exam Station Notes

Demonstrate awareness that ALS is a mixed UMN + LMN condition — state that both spastic and atrophied areas require different handling approaches within the same treatment
Show that you accommodate medical equipment (respiratory support, communication devices) as part of treatment setup
Demonstrate progressive monitoring — state that you are checking respiratory status and fatigue throughout the session
If fasciculations are observed during treatment, state that they represent active denervation and do not require treatment modification (they are a sign, not a symptom requiring intervention)

Verbal Notes

Spasm warning: before any position change or passive movement, advise: "I'm going to move your leg now — I'll go very slowly. If you feel a spasm starting, I'll hold still and wait for it to pass."
Emotional incontinence awareness: if the patient experiences involuntary laughing or crying during treatment, respond with neutral calm — do not ask "are you okay?" or draw attention to it; pseudobulbar affect is a neurological phenomenon, not an emotional response; acknowledge it once at intake: "I understand that ALS can sometimes cause sudden emotional expressions that don't match what you're feeling. If that happens during treatment, I won't be concerned — just let me know if you need a pause."
Communication adaptation: as speech declines, establish alternative communication methods before the session begins — eye blinks for yes/no, communication boards, electronic devices; confirm the method at every visit; never proceed with treatment if you cannot confirm the patient's consent and comfort level
Medical equipment: before the first treatment, ask what equipment the patient uses and how to work around it safely; confirm that respiratory support remains functional during position changes

Self-Care

Gentle passive stretching performed by a caregiver — slow, sustained holds to maintain range in joints at risk of contracture (ankles, knees, elbows, wrists); teach the caregiver safe technique and emphasize slow velocity to avoid triggering spasms
Positioning schedule — regular repositioning (every 2 hours) to prevent pressure injury and positional pain; use of pillows and wedges to maintain joint alignment
Breathing exercises — if the patient has sufficient respiratory capacity, gentle diaphragmatic breathing practice to maintain respiratory muscle function as long as possible; coordinate with respiratory therapy team

Key Takeaways

ALS is uniquely defined by simultaneous UMN and LMN degeneration — spasticity and hyperreflexia (UMN) coexist with weakness, atrophy, and fasciculations (LMN) in the same patient, distinguishing it from MS (UMN only) and peripheral neuropathies (LMN only)
Fasciculations represent active motor neuron death — denervated motor units fire spontaneously; they are visible at rest, palpable, and indicate ongoing denervation
Sensation and cognition are fully preserved — the patient feels everything and is aware of their progressive decline; client feedback on pressure is reliable
Respiratory failure is the primary cause of death; MT must monitor respiratory status, accommodate respiratory equipment, and avoid positions that compromise breathing
Heat is safe in ALS (no Uhthoff's phenomenon) — this is a critical distinction from MS
Treatment is palliative — goals are comfort, contracture prevention, and quality of life; no resistive exercise or strengthening; gentle PROM and sustained tone-reduction techniques
Sudden movements, position changes, and unexpected touch can trigger painful spasms — all handling must be slow, predictable, and verbally cued
Emotional incontinence (pseudobulbar affect) is a neurological phenomenon, not a psychiatric one — respond with calm neutrality; communication adaptations are needed as speech declines