Internal Medicine/Gait Disorders

Introduction

Gait disorders and falls are significant health concerns, particularly among the elderly population. In this comprehensive discussion, we will delve into the diverse causes of gait disorders and falls, as well as explore potential treatments and interventions aimed at reducing the risk of falls and associated injuries.

Types and Causes of Gait Disorders

Cerebellar Ataxia

Gait disorders encompass a range of conditions, each stemming from distinct causes. Cerebellar ataxia, for instance, is characterized by imbalances and staggering movements. It can be attributed to various factors, including stroke, trauma, tumors, and neurodegenerative diseases such as multiple-system atrophy and hereditary cerebellar degeneration. Notably, a short expansion at the fragile X mutation site has been linked to gait ataxia in older men. Alcohol abuse can lead to both acute and chronic cerebellar ataxia. Magnetic Resonance Imaging (MRI) plays a crucial role in visualizing the extent and topography of cerebellar atrophy in these cases.

Sensory Ataxia

Balance during locomotion relies on high-quality sensory input from visual, vestibular, and proprioceptive systems. When this information is compromised, instability ensues. Tabetic neurosyphilis is a classic example of sensory ataxia. Vitamin B12 deficiency can lead to large-fiber sensory loss in the spinal cord and peripheral nervous system. These patients exhibit diminished joint position and vibration sense in their lower limbs, making them unstable, especially with eye closure or in low-light conditions.

Neuromuscular Disease

Patients with neuromuscular diseases may experience abnormal gaits, sometimes as an initial symptom. Distal weakness, such as peripheral neuropathy, can lead to increased step height to compensate for foot drop, resulting in a characteristic slapping of the sole on the floor during weight acceptance. On the other hand, myopathy or muscular dystrophy often manifests as proximal weakness, potentially causing excess pelvic sway while walking. Lumbar spinal stenosis can lead to a stooped posture to alleviate pain from cauda equina compression during upright walking, mimicking early parkinsonism.

Toxic and Metabolic Disorders

Chronic toxicity from medications and metabolic imbalances can impair motor function and gait. These patients may exhibit mental status changes, asterixis, or myoclonus. Their static equilibrium is disrupted, making them prone to imbalance. Patients with chronic renal disease or hepatic failure may experience disequilibrium due to asterixis. Sedative drugs, particularly neuroleptics and long-acting benzodiazepines, can affect postural control and increase fall risk.

Functional Gait Disorder

Functional neurologic disorders, previously termed "psychogenic," frequently involve gait disturbances. These disorders often present with sudden onset, inconsistent deficits, waxing and waning symptoms, incongruence with organic lesions, and improvement with distraction. Various phenomenologies, including extreme slow motion, overcautious gait, odd postural gyrations, astasia–abasia, bouncing, and foot stiffness (dystonia), have been observed. These patients rarely experience falls, and there may be discrepancies between examination findings and functional status. Preceding stress or trauma may or may not be present, making diagnosis challenging.

Assessment and Diagnosis

Slowly Progressive Disorder of Gait

Assessing patients with gait disorders requires a thorough history review. It is crucial to inquire about the onset and progression of their disability. Many patients become aware of their unsteady gait following a fall. Differentiating stepwise evolution from sudden progression is key; the latter may suggest vascular disease. Gait disturbances may be associated with urinary urgency and incontinence, particularly in cases of cervical spine disease or hydrocephalus. Additionally, assessing alcohol and medication use is essential. Neurologic examination findings can aid in narrowing down potential diagnoses. Gait observation provides insight into the patient's level of disability. Arthritic and antalgic gaits can be visually recognized, while cadence, velocity, stride length, and the ability to rise from a chair can be measured.

Disorders of Balance

Balance is a dynamic state involving cerebellar, vestibular, and somatosensory systems, as well as cortical and spinal pathways. Failure at any level can lead to difficulties in maintaining posture while standing and walking. Patients with cerebellar ataxia may not complain of dizziness but exhibit visible balance impairment. Vestibular disorders often manifest as vertigo, nystagmus, and impaired standing balance. Patients with somatosensory deficits struggle with poor illumination and uneven terrain, experiencing subjective imbalance and fear of falling. Higher-level equilibrium disorders can hinder daily activities and may reduce patients' awareness of their balance impairment. Sedating medications, including neuroleptics, can exacerbate the risk of falls.

Falls

Falls are a prevalent concern among the elderly, particularly those over 65 living in the community. Falls can have severe consequences, including hip fractures, brain or spinal injuries, and a heightened risk of morbidity and mortality. Many elderly individuals voluntarily restrict their activities due to a fear of falling, which significantly impacts their quality of life. Additionally, the causes of falls are multifaceted and can include both intrinsic and extrinsic factors. Polypharmacy, or the use of multiple prescription medications, is a prominent risk factor. Understanding the history surrounding a fall event can be challenging, making diagnosis and intervention complex.

Risk Factors for Falls

The risk factors for falls are diverse, encompassing intrinsic and extrinsic elements. These factors, when present in combination, significantly increase the risk of falls. Muscle weakness, a history of falls, gait deficits, balance deficits, the use of assistive devices, visual deficits, arthritis, impaired activities of daily living, depression, cognitive impairment, and age over 80 are all established risk factors.

Assessment of the Patient with Falls

Identifying high-risk patients before severe injury occurs is crucial. All adults in the community should be annually asked about falls and any limitations in daily activities due to a fear of falling. The Timed Up and Go ("TUG") test, which involves timing a patient as they stand up from a chair, walk 10 feet, turn, and sit down, can help identify individuals at high risk for falls. The history of a fall event is often complex, with incomplete details. Patients should be questioned about provoking factors, prodromal symptoms, baseline mobility, and comorbidities. Medication reviews, particularly considering medications that increase fall risk, are essential. Distinguishing mechanical falls from those involving modifiable intrinsic factors is vital.

Types of Falls

Collapsing Falls and Drop Attacks

Some falls are characterized by a sudden loss of postural tone, leading patients to describe their legs as giving out or collapsing. Potential causes include syncope, orthostatic hypotension, atonic seizures, myoclonus, and obstructive hydrocephalus due to a colloid cyst of the third ventricle. Emotional triggers suggest cataplexy, but collapsing falls should not be confused with vertebrobasilar ischemic attacks.

Toppling Falls

Toppling falls occur when patients maintain tone in antigravity muscles but fall over like a tree trunk, disengaging postural defenses. Potential causes include cerebellar pathology and vestibular lesions, often with a consistent falling direction. These falls are characteristic of progressive supranuclear palsy in the early stages and Parkinson's disease in the later stages.

Falls Due to Gait Freezing

Gait freezing is a phenomenon observed in Parkinson's disease and related disorders. Patients experience their feet sticking to the floor while their center of mass continues to move forward, resulting in an inability to recover equilibrium, often leading to a forward fall. Similarly, individuals with Parkinson's disease and festinating gait may struggle to keep up with their feet, increasing the risk of forward falls.

Falls Related to Sensory Loss

Patients with sensory deficits, such as somatosensory, visual, or vestibular impairments, are prone to falls. These individuals find it challenging to navigate in poor lighting conditions or on uneven terrain. They often report subjective imbalance, apprehension, and fear of falling. Rehabilitation-based interventions can be particularly effective for this group.

Falls Related to Weakness

Patients lacking strength in antigravity muscles face difficulties rising from a chair or maintaining balance after perturbations. They may struggle to get up after a fall and may remain on the floor until help arrives. Deconditioning is often a treatable cause of weakness-related falls. Resistance strength training can increase muscle mass and leg strength, even in elderly individuals.

Treatment and Interventions

Interventions to Reduce the Risk of Falls and Injury

Efforts should be directed toward identifying the specific mechanisms underlying falls in each patient to enable targeted treatment. Orthostatic changes in blood pressure and pulse should be monitored, and medication reviews should reevaluate the risk-benefit profile of medications that might increase fall risk. Treating cataracts and avoiding multifocal lenses can improve vision-related falls. Home visits can identify environmental hazards, with recommendations including improved lighting, grab bars, nonslip surfaces, and adaptive equipment.

Home and Group-Based Exercise Programs

Exercise programs focused on leg strength and balance, both at home and in group settings, can reduce fall risk in individuals with a history of falls or gait and balance disorders. These programs aim to enhance muscle strength, balance stability, and resistance to injury. High-intensity resistance strength training with weights and machines is particularly effective, even for frail elderly patients. Sensory balance training can also improve stability in a few weeks, with benefits maintained through home exercises. Tai Chi programs have been shown to reduce fall risk in Parkinson's disease patients, while cognitive training, including dual-task training, can enhance mobility in older adults with cognitive impairment.