Degenerative neurologic disorders cause progressive loss of neurons. Most have no cure; care aims to relieve symptoms, preserve function and safety, prevent complications (especially aspiration and falls), and support families.

Parkinson disease (PD)

• Loss of dopamine-producing neurons in the substantia nigra → imbalance between dopamine and acetylcholine in the basal ganglia.
• Cardinal motor features: resting tremor ("pill-rolling," disappears with purposeful movement and sleep), rigidity (lead-pipe or cogwheel), bradykinesia (slowness — the key feature), and postural instability.
• Nonmotor features often come first: loss of smell, constipation, REM sleep behavior disorder, depression, orthostatic hypotension.

Atypical parkinsonism (poor response to levodopa)

• Multiple system atrophy (MSA): parkinsonism or ataxia with prominent autonomic failure — orthostatic hypotension, urinary dysfunction, erectile dysfunction.
• Progressive supranuclear palsy (PSP): early falls (often backward), axial rigidity, and vertical supranuclear gaze palsy — difficulty looking down (and up) is characteristic; downgaze problems cause trouble with stairs and eating.

Alzheimer disease (AD) and dementia

• AD is the most common cause of dementia: amyloid-beta plaques and tau neurofibrillary tangles, loss of cholinergic neurons, brain atrophy.
• Other dementias: vascular, Lewy body (visual hallucinations, parkinsonism, severe sensitivity to antipsychotics), frontotemporal (early personality and behavior change).
• Stages: mild (forgetfulness, trouble with complex tasks), moderate (confusion, wandering, needs help with ADLs, sundowning), severe (dependent, loss of speech, dysphagia).

Amyotrophic lateral sclerosis (ALS)

• Degeneration of both upper and lower motor neurons. Weakness, atrophy, fasciculations, spasticity, hyperreflexia, dysarthria, dysphagia, and eventually respiratory muscle failure.
• Sensation, bladder/bowel control, and eye movements are usually spared; cognition is often intact, though some clients develop frontotemporal dementia.
• Death usually results from respiratory failure and aspiration pneumonia.

Huntington disease (HD)

• Inherited in an autosomal dominant pattern: each child of an affected parent has a 50% chance of inheriting the gene (CAG repeat expansion in the HTT gene). Men and women are equally affected.
• Triad: chorea (involuntary jerky movements), cognitive decline, and psychiatric symptoms (depression, irritability, suicide risk). Onset typically in mid-adulthood.

Assess swallowing, nutrition and weight, fall risk, cognition (e.g., Mini-Cog, MoCA), mood, caregiver strain, and respiratory function (forced vital capacity in ALS).

• Parkinson: clinical diagnosis; clear improvement with levodopa supports it. Dopamine transporter imaging may be used when unclear.
• Alzheimer: cognitive testing; labs to exclude reversible causes (vitamin B12, thyroid function, metabolic panel, syphilis or HIV when indicated, depression screening); MRI. Amyloid PET, CSF biomarkers, or validated blood tests confirm amyloid pathology, required before anti-amyloid therapy.
• ALS: clinical findings plus EMG/nerve conduction studies; exclude mimics (e.g., cervical myelopathy). Genetic testing (e.g., SOD1).
• Huntington: genetic test for CAG repeat length. Predictive testing of at-risk adults should follow genetic counseling.

Parkinson disease

• Deep brain stimulation for motor fluctuations; physical, occupational, and speech therapy.
• Avoid dopamine-blocking drugs: haloperidol and most first-generation antipsychotics, metoclopramide, prochlorperazine. For psychosis, low-dose quetiapine, clozapine (requires neutrophil monitoring), or pimavanserin are used; all antipsychotics, including pimavanserin, carry a boxed warning for increased mortality in older adults with dementia-related psychosis.

Alzheimer disease

• Cholinesterase inhibitors (donepezil, rivastigmine, galantamine) — modest symptomatic benefit. Adverse effects: nausea, diarrhea, weight loss, bradycardia and syncope, vivid dreams (give donepezil in the morning if this occurs). Caution with conduction disease; additive bradycardia with beta blockers; GI bleeding risk rises with NSAIDs.
• Memantine (NMDA antagonist) for moderate to severe AD — dizziness, confusion, constipation; reduce dose in kidney impairment.
• Anti-amyloid monoclonal antibodies (lecanemab, donanemab) for early AD with confirmed amyloid: IV infusions that modestly slow decline. Main risk (boxed warning) is amyloid-related imaging abnormalities (ARIA) — brain edema or microhemorrhage — requiring scheduled MRI monitoring. ARIA can mimic stroke, so clients should carry a treatment card; thrombolysis needs extra caution. Risk is highest in APOE e4 homozygotes; caution with anticoagulants. Watch for infusion reactions; report headache, confusion, visual change, or seizures.
• Behavioral symptoms: treat nonpharmacologically first; antipsychotics increase mortality in dementia (boxed warning) and are reserved for severe distress or danger.

ALS

• Riluzole — modestly prolongs survival; monitor liver enzymes and neutrophil count. Edaravone (IV or oral). Tofersen (intrathecal) for SOD1-ALS.
• Noninvasive ventilation when respiratory muscles weaken (e.g., FVC below 50% predicted or symptoms of nocturnal hypoventilation) — improves survival and quality of life.
• Gastrostomy (PEG) early, before FVC falls too low for a safe procedure.
• Mechanically assisted cough, secretion management, advance care planning.

Huntington disease

• Chorea: tetrabenazine, deutetrabenazine, valbenazine (VMAT2 inhibitors). All three carry a boxed warning for depression and suicidality in Huntington disease — contraindicated in clients who are actively suicidal or have untreated depression; screen mood at every visit. Do not combine with MAO inhibitors or reserpine. Also sedation, parkinsonism, QT prolongation. Antipsychotics may also be used.
• Treat depression; high-calorie diet; genetic counseling.

Listed in priority order.

1. Airway and aspiration prevention
   • Swallow evaluation; upright for meals; thickened liquids and soft foods as ordered; small bites; suction available.
   • ALS: the most dangerous complications are aspiration pneumonia and respiratory failure — monitor FVC, SpO₂, cough strength, and dyspnea lying flat; teach breathing exercises and assisted-cough techniques as ordered; elevate head of bed; support NIV use.
2. Fall prevention
   • PD: teach to lift the toes, take large steps, walk with a wide base, and rock side to side or step over a visual line to overcome freezing; remove rugs; grab bars; rise slowly (orthostatic hypotension, especially in MSA).
   • PSP: early backward falls — supervision, assistive devices.
3. Medication timing (PD)
   • Give levodopa on time in the hospital — delayed doses cause rigidity, immobility, and aspiration risk.
   • Recognize peak-dose dyskinesia versus end-of-dose wearing-off and report patterns.
4. Cognitive support and safety (dementia)
   • Communicate with short, simple sentences, one step at a time, spoken slowly, with visual cues and gestures; approach from the front; call the client by name; avoid arguing or reality confrontation when it causes distress.
   • Consistent routine, clocks and calendars, familiar caregivers.
   • Sleep–wake: encourage daytime activity and sunlight exposure, limit daytime napping, reduce evening stimulation and caffeine to lessen sundowning and night waking.
   • Wandering: identification bracelet, door alarms; never encourage the client to go out alone.
5. Nutrition — high-calorie foods (HD, ALS); monitor weight; finger foods for dementia; constipation management (PD).
6. Communication — speech therapy, communication boards, eye-gaze devices for ALS.
7. Psychosocial and caregiver support — screen for depression and suicide risk (HD, PD); respite care; advance directives early while decision-making capacity remains.

• PD: take levodopa at consistent times; spread protein through the day; change position slowly; report hallucinations, compulsive behaviors, or sleep attacks; never stop medication suddenly; exercise (walking, cycling, tai chi) improves mobility.
• Dementia caregivers: secure medications, knives, car keys, stove knobs, and firearms; remove trip hazards; use labeled doors and night lights; consider supervised driving evaluation; plan for legal and financial decisions early.
• ALS: discuss ventilation, feeding tube, and end-of-life preferences early.
• HD genetic counseling: autosomal dominant, 50% risk for each child; the decision to have predictive testing is personal and requires counseling about emotional, family, insurance, and employment implications.

• PD = dopamine loss: resting tremor, rigidity, bradykinesia, postural instability.
• PD gait: short shuffling fast steps, forward lean; freezing = feet stuck when starting.
• Carbidopa prevents peripheral conversion of levodopa; high protein reduces absorption.
• Long-term levodopa → peak-dose dyskinesia and wearing-off; never stop abruptly.
• Avoid haloperidol, metoclopramide in PD.
• MSA → orthostatic hypotension; PSP → vertical gaze palsy (downgaze) and early falls.
• Dementia communication: short simple sentences, slowly, visual cues; day activity and sunlight for sundowning; never let client go out alone.
• Cholinesterase inhibitors → bradycardia, GI upset; anti-amyloid antibodies → ARIA, MRI monitoring.
• ALS: upper + lower motor neurons; most dangerous complication = aspiration pneumonia / respiratory failure; riluzole (liver tests); early NIV and PEG.
• Huntington: autosomal dominant, 50% per child; chorea; suicide risk; VMAT2 inhibitors.