Cognitive Contributions to Freezing of Gait in Parkinson Disease: Implications for Physical Rehabilitation

Abstract

People with Parkinson disease (PD) who show freezing of gait also have dysfunction in cognitive domains that interact with mobility. Specifically, freezing of gait is associated with executive dysfunction involving response inhibition, divided attention or switching attention, and visuospatial function. The neural control impairments leading to freezing of gait have recently been attributed to higher-level, executive and attentional cortical processes involved in coordinating posture and gait rather than to lower-level, sensorimotor impairments. To date, rehabilitation for freezing of gait primarily has focused on compensatory mobility training to overcome freezing events, such as sensory cueing and voluntary step planning. Recently, a few interventions have focused on restitutive, rather than compensatory, therapy. Given the documented impairments in executive function specific to patients with PD who freeze and increasing evidence of overlap between cognitive and motor function, incorporating cognitive challenges with mobility training may have important benefits for patients with freezing of gait. Thus, a novel theoretical framework is proposed for exercise interventions that jointly address both the specific cognitive and mobility challenges of people with PD who freeze.

Figure 1.

Overlap across models of executive function and attention., Domains within each model are grouped to show similarity among models (eg, inhibition, executive control, and selective attention). The domains in the shaded red box (broadly: inhibition and divided/switching attention) are most commonly dysfunctional in people with Parkinson disease (PD) who freeze. Dysfunction of these domains can lead to changes in functional mobility and falls in this population.

Figure 2.

(A) Example of task prioritization during agility training. The patient completes a secondary cognitive task during agility training and is instructed to switch prioritization between the mobility/stepping component (left) and the cognitive component (right). (B) Example of visual-auditory cue conflict during boxing. Simultaneously, the instructor visually cues for a left punch and verbally cues for a right punch. For this trial, the patient is instructed to respond to the visual cue only and ignore the auditory cue.