Neurologic evaluation of gait or balance disorders requires an understanding of the underlying physiology and mechanics of gait and balance.
Gait & Balance
- •Gait is a complex action that involves several systems—musculoskeletal, proprioceptive, visual, and vestibular systems
- The “task to perform” is the task that the subject intends to execute. It can be characterized by three factors: Category, specific parameters, and environmental context. These different factors are taken into account at the programming level. The central nervous system issues a command that triggers inputs to the muscular system. The muscles mobilize the bone and joint system, which produces movement. The “real task” is the task that is actually performed. In order to characterize motor activity in a noninvasive manner, peripheral variables are measured at the muscular (electromyographic activity) and movement (biomechanical quantities: kinematic and kinetic) levels. Movement efficiency is evaluated by the actual specific parameters (speed, precision, etc.).From Bouisset S, Do MC: Posture, dynamic stability, and voluntary movement, Neurophysiol Clin 38:345-362, 2008.
- •Gait phases:
- 1.Gait cycle has a stance phase (60%) and a swing phase (40%) with each lower extremity.
- 2.The basic characteristics of gait are gait speed, cadence, step length, stride length, and step width.
- •Gait and balance regulation is a complex process that involves the brain stem and spinal cord with an overall cognitive and emotional control.
- 1.The proprioceptive receptors in the lower extremities as well as the spinal reflex system have critical roles for balance during locomotion.
- 2.The reticulospinal tract is critical for maintaining muscle tone, and the connections between subthalamic and midbrain locomotor regions are also important for control of gait and balance.
- 3.The cerebellum has several connections including reciprocal ones with cortical areas (parietal, motor) and basal ganglia, affecting balance and gait.
- 4.Cortical control: The supplementary and premotor areas are thought to be involved in initiation of movements. In addition, visuospatial orientation of the body in space is required for precise movements and requires further coordination with the cerebellum. Accurate cognitive information through the temporoparietal cortex is required for accurate gait in unfamiliar surroundings.
- •Gait is usually acquired by around 12 mo of age (mean of 11 to 14.5 mo).
- •Several factors contribute to age-related gait and balance difficulties.
- •Decreased visual acuity, decreased proprioception, and impaired integration with higher cortical functions and connectivity, as well as processing speed, are some of the factors that contribute to age-related gait difficulties.
- •With aging, by age 85 yr, only 1 in 10 people have normal gait.
- •Falls are a serious risk in those older than age 65 yr and can have severe morbidity (e.g., fracture of neck of femur) and can lead to further debilitation.
- •Preventive measures aimed at improving cognitive and physical activities can decrease the risk of falls in the older population.
Typically occur when there is an alteration in the complex pathway of gait and can occur at any level of the process
- •Initiation: Cerebral cortex and the emotion-based limbic system
- •Regulation: Cerebral cortex, basal ganglia, and cerebellum
- •Execution: Brain stem, spinal cord, and the motor units
- •The primary goal is to identify and treat correctable causes.
- •A detailed history and thorough neurologic examination are critical to ascertain the cause of the gait disturbance and can suggest the neuraxial level of the lesion.
- •Major considerations include the following:
- 1.Sudden onset of imbalance or gait abnormalities suggest vascular causes.
- 2.Increased fatigue with generalized muscle weakness can be due to upper motor neuron disease.
- 3.Positional changes with increased muscle tone evident only during walking may be seen in dystonia.
- 4.Proximal muscle weakness can cause difficulty arising from sitting position or climbing stairs and are related to myopathies.
- 5.Distal muscle weakness can cause gait abnormalities (steppage gait) and falls and are due to peripheral neuropathies.
- 6.Unsteadiness while walking with eyes closed or in the dark is from loss of proprioception, and seen in sensory ataxias.
- 7.Pain with walking can be neurogenic or vascular.
- a.When exacerbated by extension of the spine and relieved by leaning forward, it suggests neurogenic claudication.
- b.Pain in the calves of the legs that limits walking suggests a vascular cause.
- 8.Bladder and/or bowel involvement signals spinal cord lesion.
- 9.Involvement of higher mental functions with bladder/bowel dysfunction and gait abnormalities suggests cortical level of lesion.
- •Nonneurologic causes (and not related to natural aging) are not discussed in detail in this review; they include osteoarthritis and other orthopedic and rheumatologic causes.
- 1.Typically do not have associated muscle weakness, sensory loss, or change in deep tendon reflexes
- 2.Cause shorter strides, prolonged stance phase, and decreased range of motion
- 3.Orthopedic gait disorders typically have asymmetric gait pattern (limping)
- 4.Medication-related causes, especially in the elderly: Polypharmacy; sedatives
- •Functional or psychogenic gait disorders:
- 1.Any type of gait abnormality may be present.
- 2.Usually of abrupt onset.
- 3.Resolution or improvement with distraction, inconsistency with clinical findings, absence of injuries from falls, and so on, are some signs that may signal the diagnosis.
- •Neurologic causes:
- 1.Hypokinetic gait abnormalities: Parkinsonian disorders
- 2.Ataxic: Sensory ataxia, cerebellar ataxia
- 3.Spastic: Hemiparetic, paraparetic
- 4.Dystonic gait
- 5.Choreatic gait
- 6.Frontal gait
Phenomenologic Classification of Gait Disorders
From Pirker W, Katzenschlager R: Gait disorders in adults and the elderly: a clinical guide, Wien Klin Wochenschr 129(3-4):81-95, 2017.
|Hemispastic gait||Unilateral extension and circumduction|
|Paraspastic gait||Bilateral extension and adduction, stiff|
|Ataxic gait||Broad-based, lack of coordination|
|Sensory ataxic gait||Cautious, worsening without visual input|
|Cautious gait||Broad-based, cautious, slow, anxious|
|Freezing gait||Blockage, e.g., on turning|
|Propulsive gait||Center of gravity in front of body, festination|
|Astasia||Primary impairment of stance/balance|
|Dystonic gait||Abnormal posture of foot/leg|
|Choreatic gait||Irregular, dancelike, broad-based|
|Steppage gait||Weakness of foot extensors|
|Waddling gait||Broad-based, swaying, drop of swinging leg|
|Antalgic gait||Shortened stance phase on affected side|
|Vertiginous gait||Insecure, tendency to fall to one side|
|Psychogenic gait disorder||Bizarre, rarely falls|
Hypokinetic Akinetic Rigid Syndromes
Parkinson Disease (PD): 80% of All Parkinsonism
- •Primarily a disorder of the basal ganglia and its connections with the cortex and spinal cord.
- •Both postural orientation and stabilization control are lost.
- •Onset is typically with resting hand tremor.
- •Hypobradykinetic type of gait abnormality; slowing when turning is usually the first sign.
- •Asymmetric changes are seen during earlier stages of the disease.
- •Later stages show “start hesitancy,” followed by shuffling gait, festination, and freezing, and in very late stages imbalance and falls are noted.
Progressive Supranuclear Palsy (PSP)
- •Neurodegenerative disease from abnormal tau protein deposition in the brain.
- •Falls—typically backward—usually occur early in the disease (in contrast to PD).
- •Vertical supranuclear ophthalmoplegia is the hallmark feature.
- •Broad-based and rigid gait with a hyperextended neck and postural instability.
Multisystem Atrophy (MSA)
- •Neurodegenerative disorder from alpha-synucleinopathy
- •Autonomic dysregulation is seen early in the disease or can precede it by years
- •Symmetric signs without tremors and early falls
- •Has combined parkinsonian and cerebellar symptoms
- •From diseases of the midline cerebellum.
- 1.Typically from vascular, neoplastic, or inflammatory causes
- 2.Can be episodic if due to toxic causes—alcohol, medications
- •At baseline has a broad-based stance with truncal instability and head titubation.
- •The initiation of gait is normal, but it is lurching with an inability to tandem walk with or without eyes open.
- •Due to disturbances in proprioception from large-fiber neuropathies or dorsal root or dorsal column disorders (e.g., vitamin B12 deficiency)
- •At baseline has a broad-based stance and walks cautiously with visual assistance
- •Ataxia is pronounced in darkness due to the absence of visual cues to compensate for the loss of proprioceptive sense
- •High risk of falls especially with unknown or uneven terrain
Combined Cerebellar and Sensory Ataxia
- •Seen with some hereditary ataxias: Spinocerebellar ataxia with polyneuropathy
- •Has mixed features
- 1.Unilateral increased tone of muscles resulting in an asymmetric circumductive movement on the paretic side
- 2.Wide-based stance with poor balance and slow movements
- 3.Typically seen after vascular insults along the corticospinal tract
- 1.There is increased tone of the leg adductors that results in bilateral circumduction and a “scissors gait.”
- 2.Causes include hereditary spastic paraparesis or acquired spastic paraparesis (infections [HTLV1], spinal cord compression, etc.).
- •Can cause bizarre postures and gait, posing diagnostic challenges
- •Excessive flexion at the hip is a classic sign.
- •Can be primary or secondary
- •Primary: Onset in childhood; can be related to a specific action, can be subtle, and can eventually become generalized
- 1.Dopa-responsive dystonia: Diurnal fluctuations; dramatic response to levodopa
- •Secondary: Due to a specific cause
- 1.Tardive dyskinesia from chronic use of dopamine receptor blockers
- •Characterized by sudden involuntary movements with variability in stance, cadence, and length of the gait
- •Has a wide-based stance with dancelike swaying movements
- •Can be due to several causes:
- 1.Huntington disease: Combination of chorea, ataxia, and parkinsonism causes complex gait disorder with frequent falls
- 2.Post–cardiopulmonary bypass surgery
- •Results from disruptions in the connections between cortical and subcortical regions that control gait
- •Mixed gait disturbances occur with wide-based ataxic and/or akinetic-rigid gait
- •Can have greater difficulty to initiate gait and appears to have feet “glued” to the floor (“magnetic gait”) with frequent falls
- •Frontal release signs are seen: Paratonic rigidity of limbs, grasp reflex
- •Typical causes include frontal lobe tumors, normal pressure hydrocephalus, and diffuse cerebrovascular small vessel disease
- 1.“Lower half parkinsonism,” from diffuse cerebrovascular small vessel disease, involves only the trunk and lower limbs
- 1.Limit the number of medications in the elderly.
- 2.Use the lowest dose that is effective.
- 1.Ensure no underlying rare organic causes.
- 2.Physical therapy and psychiatric support when diagnosis is confirmed.
- •Correction of underlying etiology can improve symptoms (e.g., vitamin B12 replacement in deficiency, dopa-responsive dystonia).
- •All patients will benefit from physical therapy and rehabilitation.
- •Virtual reality training, mirror therapy, biofeedback, acupuncture, robotic-assistive devices, functional neuromuscular stimulation, noninvasive brain stimulation, and brain-computer interfaces are modalities that have been tried to improve mobility in neurologic disorders, with varying success.
- •In addition to medical treatment, targeted physical and occupational rehabilitation therapies can assist to maintain and improve range of motion, mobility, and flexibility and ensure safety.
- •Parkinson disease:
- 1.The Unified Parkinson Disease Rating Scale has been shown to improve with exercise.
- 2.With progression of disease or with poor response to medical treatment, deepbrain stimulation with pulse generators in the thalamus or substantia nigra or globus pallidus interna have been shown to be of benefit.
- •MSA and PSP: Harder to treat medically, but symptomatic treatments can improve quality of life.
Functional recovery was 95% after stroke at 13 wk with rehabilitation.
- •Gait is a complex function that involves all parts of the neuraxis.
- •Normal aging can cause gait difficulties and falls. Exercise and balance training along with correction of visual disturbance can prevent age-related gait disorders and falls.
- •Gait abnormalities can be due to nonneurologic as well as neurologic causes.
- •Early identification of the causes of gait disorders can lead to early intervention.
- •Physical therapy and rehabilitation, in addition to medical and several nonmedical interventions, are available and beneficial to treat gait disorders.
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- 9. Jørgensen HS: The Copenhagen stroke study experience, J Stroke Cerebrovasc Dis 6(1):5–16, 1996.