3.4 Parkinson's Disease, MS, ALS, & GBS

Parkinson's Disease (PD)

Parkinson's disease (PD) is a progressive disorder caused by loss of dopamine-producing neurons in the substantia nigra of the basal ganglia. The cardinal motor signs are remembered as TRAP: Tremor (resting, 4-6 Hz, pill-rolling), Rigidity (cogwheel), Akinesia/bradykinesia (slow, small movement), and Postural instability. Patients also show a stooped (kyphotic) posture, shuffling festinating gait, hypokinesia, masked facies, micrographia, and freezing episodes — especially at thresholds, turns, and doorways.

Hoehn and Yahr Staging

PTA Interventions

• LSVT BIG (Lee Silverman Voice Treatment BIG) principles train large-amplitude, high-effort movement to counteract hypokinesia; the PTA cues the patient to move "BIG."
• External cueing bypasses the impaired internal movement drive: visual lines on the floor to step over, an auditory metronome or music for cadence, and rhythmic counting to initiate and sustain gait.
• Strategies for freezing: stop, reset posture, shift weight side to side, then step to a cue rather than pushing forward (which causes festination and falls).
• Emphasize posture extension, trunk rotation, reciprocal arm swing, balance, and fall prevention. Schedule sessions during peak "on" medication time (typically 45-60 minutes after a levodopa dose) and watch for end-of-dose "off" wearing.

Multiple Sclerosis (MS)

Multiple sclerosis (MS) is an autoimmune demyelinating disease of the central nervous system, often following a relapsing-remitting course. Symptoms vary widely: fatigue, weakness, spasticity, sensory loss, ataxia, optic neuritis and visual changes, intention tremor, and bowel/bladder dysfunction.

Key PTA Precautions

• Fatigue management is central. Fatigue is one of the most disabling MS symptoms. The PTA uses energy conservation, activity pacing, frequent rest breaks, and submaximal exercise; the goal is consistent function, not exhaustion.
• Uhthoff's phenomenon: a rise in core body temperature transiently worsens MS symptoms. Keep the patient cool — cooler treatment rooms, cooling garments, hydration, exercising in the cooler part of the day, and avoiding hot modalities, hot tubs, or overheating.
• Train balance, gait, and strength at submaximal intensities; avoid overwork weakness.

Amyotrophic Lateral Sclerosis (ALS)

Amyotrophic lateral sclerosis (ALS), or Lou Gehrig's disease, is a progressive degeneration of both upper and lower motor neurons, producing a mix of spasticity and flaccid weakness with atrophy and fasciculations. It is relentlessly progressive and currently terminal, usually from respiratory failure.

Key PTA Precautions

• Monitor respiratory status closely. Respiratory muscle weakness is the leading cause of death; watch for shortness of breath, weak cough, orthopnea, and reduced endurance, and report changes promptly.
• Avoid fatiguing, high-intensity exercise — overwork can permanently worsen weakness in already-failing muscles. Use gentle, submaximal activity.
• Focus on function, energy conservation, contracture prevention (PROM and stretching), safe mobility, caregiver training, and timely equipment (assistive devices, wheelchair, orthotics, communication aids) as the disease progresses.

Guillain-Barre Syndrome (GBS)

Guillain-Barre syndrome (GBS) is an acute, immune-mediated polyneuropathy, often following a respiratory or gastrointestinal infection. It classically produces a rapid, ascending, symmetrical paralysis beginning in the legs and moving upward, with risk to the respiratory muscles in severe cases (some patients require mechanical ventilation). Unlike ALS, GBS is usually followed by gradual recovery over weeks to months, typically in a descending pattern, with most patients regaining substantial function.

Key PTA Precaution

• During the recovery phase, overexertion can worsen outcomes. The PTA uses submaximal, non-fatiguing exercise, frequent rest, and gradual progression as strength returns. Acutely, monitor respiratory status and vital signs; later, prevent contractures and overwork while progressively rebuilding endurance and function within the plan of care.

The Overwork-Weakness Rule and Quick Comparison

Three of these four conditions (MS, ALS, GBS) share a single high-yield rule: fatiguing, maximal exercise can cause overwork weakness and is contraindicated — submaximal, paced activity is the answer. Only PD reliably tolerates and benefits from high-effort, large-amplitude work.

Distinguishing the Four on the Exam

The NPTE-PTA rarely asks for a diagnosis directly; it gives a scenario and asks for the safe action. Use these discriminators. A patient who freezes in doorways, shuffles, and benefits from a metronome is PD — push large-amplitude, high-effort movement. A patient whose symptoms flare when the room is warm or after a hot shower is MS (Uhthoff's) — cool and pace. A patient with mixed spasticity-and-atrophy plus a weakening cough is ALS — monitor respiration and avoid fatigue. A patient with a recent infection followed by rapidly rising leg-to-trunk weakness is GBS — protect against overexertion and watch breathing acutely.

A second high-yield contrast is ALS versus GBS, which both threaten respiration but differ in trajectory: ALS is degenerative and progressive (function will decline, so the plan emphasizes adaptation and equipment), whereas GBS is acute and self-limited (function will return, so the plan rebuilds endurance gradually without overworking partially reinnervated muscle). Confusing the prognosis leads to the wrong goal and the wrong exam answer.

Across all four conditions, the PTA documents objective changes — new fatigue thresholds, declining cough, increased freezing, heat intolerance — and reports them to the supervising PT, who adjusts the plan of care.