Gait Disorders, Imbalance, and Falls¶
Chapter 28 | Part 2: Cardinal Manifestations and Presentation of Diseases · Part 2 – Cardinal Manifestations & Presentation · Chapter 28
Key Clinical Points¶
- Balance requires integration of visual, vestibular, and proprioceptive inputs; loss of any two pathways compromises stability.
- Prevalence of gait disorders is high in the elderly (15% in >65 years; ~40% in >85 years).
- Frontal gait disorder (higher-level) is common in the elderly, often caused by vascular disease or NPH.
- Parkinsonian gait features include stooped posture, shuffling, decreased arm swing, festination, and freezing.
- Sensory ataxia is characterized by a positive Romberg sign, worsening in the dark, and looking at feet while walking.
- Cerebellar ataxia presents with wide-based gait, truncal sway, and late falls.
- Fall risk factors include intrinsic (vision, gait, weakness) and extrinsic (environment); polypharmacy is a major modifiable risk.
- TUG test >12 seconds indicates high risk for falls.
- Functional gait disorder presents with sudden onset, inconsistent deficits, and improvement with distraction.
- Hip fractures from falls significantly increase mortality risk and lead to potential nursing home admission.
DEFINITION & CLASSIFICATION¶
• Balance: Ability to maintain equilibrium—a dynamic state where center of mass is controlled relative to lower extremities, gravity, and support surface despite perturbations. • Sensory Inputs: Primarily generated by visual, vestibular, and proprioceptive systems (muscle spindles/joints). • Redundancy: Healthy redundancy exists; loss of 2 out of 3 pathways → compromised standing balance. • Mechanism: ◦ Brainstem, cerebellum, and forebrain modify spinal pattern generators to promote stepping. ◦ Step generation in primates depends on pontine tegmentum, midbrain, and subthalamic region. ◦ Reticular formation and descending pathways (ventromedial spinal cord) execute locomotor synergies. ◦ Cerebral control provides goal/purpose, obstacle avoidance, and adaptation to terrain. • Postural Control: Requires maintaining center of mass over base of support; includes long latency responses (starting 110 milliseconds after perturbation). • Failure Points: Can occur at any level → presents as difficulty maintaining posture while standing or walking.
Anatomy and Physiology of Gait¶
• Complexity: Bipedal walking is complex; even minor neurologic deficits can compromise performance. • Clinical Observation: Gait disorders are often viewed as a product of a neurologic deficit combined with functional adaptation. • Adaptation: Unique features of failing gait are often masked by adaptive responses to threatened balance.
EPIDEMIOLOGY¶
• Prevalence: ◦ Age >65: 15% have gait disorders. ◦ Age ≥80: 1 in 4 use a mechanical aid for ambulation. ◦ Age ≥85: Prevalence approaches 40%. • Fall Risk: ◦ Over 1/3 of people >65 living in the community fall annually (higher rate in nursing homes/hospitals). ◦ Impact: Hip fractures → hospitalization, potential nursing home admission, and increased mortality risk. ◦ Secondary Risks: Dehydration, rhabdomyolysis (from prolonged time on ground), and brain/spinal injury. • Psychological Impact: 1 in 5 elderly individuals restrict activity due to fear of falling; loss of ambulation reduces quality of life.
ETIOLOGY & PATHOPHYSIOLOGY¶
• Non-neurologic causes: Antalgic gait (osteoarthritis), asymmetry (contractures/orthopedic deformities), and impaired vision. • Neurologic Gait Disorders: ◦ Sensory ataxic: Peripheral sensory neuropathy. ◦ Parkinsonian: Parkinson's disease, drug-induced parkinsonism, dementia with parkinsonism. ◦ Higher level: Vascular encephalopathy, normal pressure hydrocephalus (NPH), severe dementia, hypoxic ischemic encephalopathy. ◦ Cerebellar ataxic: Cerebellar stroke, MS, essential tremor, postvaccinal cerebellitis, chronic alcohol abuse, multiple system atrophy. ◦ Cautious: Idiopathic, associated fear of falling. ◦ Paretic/hypotonic: Neurogenic claudication, diabetic neuropathy, trauma/surgery injury, GBS. ◦ Spastic: Ischemic stroke, intracerebral hemorrhage, congenital. ◦ Vestibular ataxic: Bilateral vestibulopathy, vestibular neuronitis, Ménière's attack, acoustic neuroma. ◦ Dyskinetic: Levodopa-induced dyskinesia, chorea.
Classification of Gait Disorders¶
• Descriptive Classification: Based on abnormal physiology and biomechanics (e.g., sensory ataxic, parkinsonian). ◦ Note: Many failing gaits look similar due to common patterns of adaptation to threatened balance.
Prevalence of Neurologic Gait Disorders¶
Table 28-1 provides the breakdown of cases: • Sensory ataxic: 18% (46 total) → Peripheral sensory neuropathy. • Parkinsonian: 16% (34 total) → PD, drug-induced, dementia with parkinsonism. • Higher level: 8% (31 total) → Vascular encephalopathy (20), NPH (1), severe dementia (7). • Cerebellar ataxic: 6% (10 total) → Stroke, MS, essential tremor, alcohol abuse. • Cautious: 6% (7 total) → Idiopathic/fear of falling. • Paretic/hypotonic: 5% (14 total) → Neurogenic claudication, diabetic neuropathy, trauma. • Spastic: 5% (7 total) → Stroke, hemorrhage. • Vestibular ataxic: 3% (6 total) → Vestibulopathy, neuronitis, Ménière's. • Dyskinetic: 1% (4 total) → Levodopa-induced dyskinesia, chorea.
CLINICAL FEATURES¶
• General Observations: Gait is primarily assessed via observation; cadence, velocity, and stride length can be measured. • Parkinsonian Features: ◦ Stooped posture, shuffling gait, decreased arm swing, festination, and freezing of gait. ◦ Differentiation: ◦ PSP: More erect posture than PD; falls within first year suggest PSP. ◦ Vascular Parkinsonism: Broad-based/shuffling with reduced arm swing; disproportionate involvement of gait early in course. • Frontal Gait Disorder (Higher-level): ◦ Characteristics: Shuffling, freezing, wide base, short stride, difficulty with starts and turns. ◦ 'Slipping clutch' syndrome: Difficulty with gait initiation. ◦ Etiology: Most common cause is vascular disease (subcortical small-vessel). ◦ NPH: Presents with similar gait; MRI shows ventricular enlargement and periventricular white matter change. • Cerebellar Gait Ataxia: ◦ Characteristics: Wide base, truncal sway, erratic foot placement, difficulty turning. ◦ Clinical signs: Inability to walk tandem heel-to-heel. • Sensory Ataxia: ◦ Features: Romberg positive, worse in dark, patient looks down at feet. ◦ Mechanism: Loss of proprioception requires active visual monitoring. • Vestibular Disorders: ◦ Symptoms: Vertigo (subjective), nystagmus, impaired standing balance. ◦ Ototoxic drugs: May lack vertigo/nystagmus but have impaired balance and difficulty in the dark. • Neuromuscular Disease: ◦ Steppage gait: Increased step height to compensate for foot drop (peripheral neuropathy). ◦ Myopathy/Dystrophy: Proximal weakness → excess pelvic sway. • Functional Gait Disorder: ◦ Features: Sudden onset, inconsistent deficits, waxing/waning, improvement with distraction. ◦ Presentation: Slow motion, overcautious gait, astasia-abasia, bouncing. • Other Disorders: ◦ Orthostatic tremor: High-frequency, low-amplitude; worse on standing. ◦ Lumbar spinal stenosis: Stooped posture to alleviate pain (mimics early parkinsonism). ◦ Dyskinetic: Dancing quality (Huntington's), stereotypic patterns (Tardive dyskinesia).
Comparative Features of Ataxias¶
Table 28-2 summarizes the differences between Cerebellar, Sensory, and Frontal Gait: • Cerebellar: Wide-based; Irregular/lurching stride; Abnormal heel → shin; Unsteady turns; Late falls. • Sensory: Wide-based (looks down); Regular stride with path deviation; ± Romberg; Frequent falls. • Frontal: Wide-based; Short, shuffling stride; Normal heel → shin; Hesitant/multistep turns; Frequent falls.
DIFFERENTIAL DIAGNOSIS¶
• By Etiology: ◦ Neurologic (Parkinsonian, Cerebellar, etc.) vs. Non-neurologic (Pain/Arthritic, Vision, Vestibular). • By Physiology and Biomechanics: ◦ Distinction between motor control issues (Frontal), sensory deficits (Sensory Ataxia), and vestibular dysfunction.
DIAGNOSTIC APPROACH¶
- History Taking: ◦ Identify fall patterns: Sudden drop → suspect syncope, seizure, or neuro event; Tripping/slipping → mechanical/environmental. ◦ Assess prodromal symptoms: Dizziness, vertigo, presyncopal symptoms, focal weakness. ◦ Review medications: Benzodiazepines, opioids, antipsychotics, antiepileptics, antidepressants, antiarrhythmics, diuretics. ◦ Determine duration and consistency of gait issues (Sudden/inconsistent → Functional).
- Physical Examination: ◦ Observe gait parameters: Cadence, velocity, stride length. ◦ Perform Romberg test to assess sensory/vestibular input. ◦ Assess for 'slipping clutch' or festination (Parkinsonian signs). ◦ Conduct cardiac examination (especially in patients with sudden falls).
- Diagnostic Tests: ◦ MRI: Sensitive for cerebral lesions (vascular, demyelinating) and screening for hydrocephalus. ◦ Lumbar puncture/dynamic test: Required to confirm NPH.
MANAGEMENT & TREATMENT¶
- Pharmacologic Management: ◦ Dopaminergic drugs: Optimize for patients with freezing of gait. ◦ MAO-B inhibitors: Use rasagiline or selegiline to improve end-of-dose gait freezing.
- Non-Pharmacologic Management: ◦ Instrumentation: Use of instrumented walkways for quantitative analysis. ◦ Cueing: Implementation of auditory and visual cueing strategies to overcome freezing. ◦ Environmental modification: Address extrinsic factors like wet surfaces or improper footwear.
COMPLICATIONS & PROGNOSIS¶
• Fall Consequences: ◦ Physical injury (fractures, head trauma). ◦ Reduced mobility → loss of independence. ◦ Increased mortality risk (especially from hip fractures). • Quality of Life: ◦ Fear of falling leads to self-imposed activity restriction. ◦ Loss of ambulation correlates with increased morbidity and mortality.
SPECIAL POPULATIONS¶
• Cognitive Impairment: Patients with dementia are at higher risk for falls and injury. • Metabolic/Toxic Disorders: ◦ Chronic renal disease or hepatic failure → asterixis → impaired postural support. ◦ Drug toxicity: Neuroleptics and long-acting benzodiazepines significantly increase fall risk.
KEY PEARLS & HIGH-YIELD POINTS¶
• TUG Test: Score >12 seconds → high risk for falls. • Frontal Gait: Often a 'higher-level' motor control disorder, not an apraxia; most common cause is subcortical vascular disease. • Sensory Ataxia: Characterized by the need for visual compensation (looking at feet) and failure in dark/closed eyes. • Cerebellar Ataxia: Falls are typically a 'late' event as patients use postural compensation early on. • Risk Factors Table: Table 28-3 lists key risk factors: History of falls, Gait/balance disorder, Visual deficits, Physical disability (weakness, OA), Orthostatic hypotension, Depression, Cognitive impairment, and Polypharmacy.
Reference Tables¶
TABLE 28-1 Prevalence of Neurologic Gait Disorders¶
Harrison's 22e, p.177
| NEUROLOGIC GAIT DISORDER | NO. (%)a | TOTAL NUMBERb | CAUSES (NO.) |
|---|---|---|---|
| Single neurologic gait disorder | 81 (69%) | ||
| Sensory ataxic | 22 (18%) | 46 | Peripheral sensory neuropathy (46) |
| Parkinsonian | 19 (16%) | 34 | Parkinson’s disease (18), drug-induced parkinsonism (8), dementia with parkinsonism (4), parkinsonism (4) |
| Higher level | 9 (8%) | 31 | Vascular encephalopathy (20), normal pressure hydrocephalus (1), severe dementia (7), hypoxic ischemic encephalopathy (1), unknown (1) |
| Cerebellar ataxic | 7 (6%) | 10 | Cerebellar stroke (3), cerebellar lesion due to multiple sclerosis (1), severe essential tremor (3), postvaccinal cerebellitis (1), chronic alcohol abuse (1), multiple system atrophy (1) |
| Cautious | 7 (6%) | 7 | Idiopathic, associated fear of falling (7) |
| Paretic/hypotonic | 6 (5%) | 14 | Neurogenic claudication (7), diabetic neuropathy (1), nerve lesion due to trauma or surgery (4), distal paraparesis after Guillain-Barré syndrome (1), unknown (2) |
| Spastic | 6 (5%) | 7 | Ischemic stroke (3), intracerebral hemorrhage (3), congenital (1) |
| Vestibular ataxic | 4 (3%) | 6 | Bilateral vestibulopathy (3), recent vestibular neuronitis (1), recent Ménière’s attack (1), acoustic neuroma with surgery (1) |
| Dyskinetic | 1 (1%) | 4 | Levodopa-induced dyskinesia (3), chorea (1) |
| 36 (30%) | |||
| Total | 117 |
TABLE 28-2 Features of Cerebellar Ataxia, Sensory Ataxia, and Frontal Gait Disorders FEATURE Base of support Velocity…¶
Harrison's 22e, p.179
| FEATURE | CEREBELLAR ATAXIA | SENSORY ATAXIA | FRONTAL GAIT |
|---|---|---|---|
| Base of support | Wide-based | Wide-based, looks down | Wide-based |
| Variable | Slow | ||
| Stride | Irregular, lurching | Regular with path deviation | Short, shuffling |
| +/– | Unsteady, falls | ||
| Heel → shin | Abnormal | +/– | Normal |
| Normal | Normal | ||
| Turns | Unsteady | +/– | Hesitant, multistep |
| + | +++ | ||
| Falls | Late event | Frequent | Frequent |
TABLE 28-3 Common Risk Factors for Falls in Older Adults¶
Harrison's 22e, p.180
- RISK FACTOR
- History of falls
- Gait and/or balance disorder
- Visual deficits
- Physical disability
• Includes muscle weakness, use of assistive devices, osteoarthritis of the knee - Orthostatic hypotension
- Depression
- Cognitive impairment
- Medications
• Polypharmacy, use of antipsychotics, antidepressants, benzodiazepines,
anticholinergics, antihypertensives, and diuretics