How Parkinson's Disease Affects Walking Ability
Parkinson's disease profoundly impairs walking through multiple interconnected mechanisms including rigidity, bradykinesia, postural instability, impaired balance control, and deficits in motor learning and sensory integration, which collectively increase fall risk and reduce mobility—particularly in geriatric patients where these effects are compounded by age-related sensory and motor decline. 1
Core Motor Impairments Affecting Gait
Primary Parkinsonian Features
Rigidity creates constant resistance to movement throughout the entire range of motion, increasing energy expenditure during walking and contributing to the characteristic shuffling gait pattern 2
Bradykinesia (slowness of movement) directly reduces walking speed and stride length, forcing patients to walk slowly in part to compensate for their balance control deficit 3
Postural instability emerges as a cardinal feature, with gait and balance problems taking on critical importance in cognitively impaired elderly patients with PD 1
Balance and Stability Deficits
Patients with PD demonstrate reduced stability in the forward direction and inability to produce proactive anticipatory adjustments when walking 4
Balance control deficits account for much of the walking difficulty, though providing balance support alone does not fully restore normal walking speed—suggesting additional mechanisms beyond pure balance impairment 3
Fall risk is substantially increased when gait and balance problems co-occur with cognitive or behavioral impairments in insight, judgment, impulse control, attention, memory, and visuospatial awareness 1
Motor Learning and Adaptation Problems
Impaired Learning Systems
PD causes degradation of motor learning, particularly automatic responses to feedback are faulty, resulting in reliance on feedforward systems of movement learning and control 5
Patients require more training to achieve and retain motor learning and may need additional sensory information or motor guidance to facilitate learning 5
Set-changing problems are severe enough that patients may hold assistive devices off the ground when walking, suggesting their cognitive inflexibility aggravates walking difficulty 3
Sensory Integration Deficits
Poor sensory integration, inflexible program selection, and impaired cognitive processing limit mobility in people with PD 6
Patients are unable to maintain motor gains in environments requiring divided attention (such as dual-tasking) 5
They cannot adapt to gradual sensory and motor degradation, contributing to progressive gait deterioration 5
Functional Impact and Quality of Life
Mobility Consequences
Impairment in balance during functional activities and reduction in walking capacity are the most important factors negatively affecting quality of life perception in PD patients 7
Lower balance scores and shorter walking distances correlate with poorer quality of life, particularly affecting mobility and daily living activities domains 7
Patients walk at speeds between disease-free older adults and older adults with muscle weakness and history of falling 3
Clinical Manifestations
Freezing of gait can occur, representing one of the most disabling motor symptoms 1
The combination of tremor with rigidity produces the characteristic "cogwheel" phenomenon during passive movement examination 2
Postural instability and gait disability (PIGD) represent a distinct symptom cluster that is particularly resistant to dopaminergic therapy 5
Critical Clinical Pitfalls
Diagnostic Considerations
Early prominent gait dysfunction and postural instability are red flags for atypical parkinsonian syndromes (like Multiple System Atrophy) rather than typical PD—this distinction is crucial as prognosis and treatment differ significantly 8
Do not confuse parkinsonian rigidity with spasticity—rigidity shows constant resistance while spasticity is velocity-dependent 2
Missing subtle rigidity without using activation maneuvers (having the patient perform movements with the contralateral limb during examination) 2
Assessment Requirements
Gait disorder can be the most prominent symptom in some patients and has predictive utility for future dementia risk 1
Falling in dementia with Lewy bodies (a Parkinson's spectrum disorder) is associated with substantial morbidity and mortality 1
Distal polysensory neuropathy in the feet/legs is common in older individuals and compounds fall risk—this should be assessed and treated (e.g., vitamin B12 deficiency) or mitigated with assistive devices 1
Therapeutic Implications
Exercise and Rehabilitation
Physical and exercise therapy can help patients adapt new feedforward strategies to partially counteract gait symptoms, with balance, treadmill, resistance, and repeated perturbation training showing improvement in motor patterns 5
A single session of perturbation-based balance training can produce acute effects that ameliorate gait instability in PD 4
Constraint-focused agility exercise programs incorporating movement principles from tai chi, boxing, lunges, and Pilates can address specific mobility limitations 6
Endurance and resistance exercises may slow disease progression and improve functionality and quality of life 1
Intervention Strategies
Formal physical therapy assessment and treatment of gait and balance, home occupational therapy, and safety assessment should be implemented early, as improved balance or limb motor function can benefit daily functions and reduce safety risks 1
Environmental modifications (night lights, shower grab bars, eliminating trip hazards) are essential fall prevention strategies 1
Deep brain stimulation reduces rigidity by modulating abnormal basal ganglia circuit activity, which also decreases energy expenditure from muscle stiffness 2
Monitoring Requirements
Regular monitoring of nutritional and vitamin status is recommended, with particular attention to body weight changes and supplementation of vitamin D, folic acid, and vitamin B12 1
Depression is a predictor of malnutrition and reduces ability to participate in rehabilitation, predicting patients who will not show functional improvement after intervention 9