Freezing of gait in Parkinson's disease: disturbances in automaticity and control

Abstract

Recent studies emphasize a key role of controlled operations, such as set-shifting and inhibition, in the occurrence of freezing of gait (FOG) in Parkinson's disease (PD). However, FOG can also be characterized as a de-automatization disorder, showing impairments in both the execution and acquisition of automaticity. The observed deficits in automaticity and executive functioning indicate that both processes are malfunctioning in freezers. Therefore, to explain FOG from a cognitive-based perspective, we present a model describing the pathways involved in automatic and controlled processes prior to a FOG episode. Crucially, we focus on disturbances in automaticity and control, regulated by the frontostriatal circuitry. In complex situations, non-freezing PD patients may compensate for deficits in automaticity by switching to increased cognitive control. However, as both automatic and controlled processes are more severely impaired in freezers, this hampers cognitive compensation in FOG, resulting in a potential breakdown. Future directions for cognitive rehabilitation are proposed, based on the cognitive model we put forward.

Freezing of gait and affective theory of mind in Parkinson disease

“…When the latter are hampered and cognitive resources are insufficient to handle a challenging situation, a FOG episode could possibly occur. Our findings are in line with the theory of a cognitive-motor-affective "conflict" in the basal ganglia, as the origin of FOG and might suggest that a deficit in the affective resources may also have an influence on the occurrence of freezing episodes [33].…”

Does Anxiety Cause Freezing of Gait in Parkinson's Disease?

“…In contrast, the cognitive model suggests that freezing of gait is an outcome of a conflict-resolution deficit, specifically exacerbated in situations where response selection and inhibition of unwanted responses are necessary [51]. This model also emphasizes that executive dysfunction might enhance freezing behaviours in these situations.…”

Cortical correlates of susceptibility to upper limb freezing in Parkinson’s disease

“…Altered function of these areas parallel executive dysfunctions (Kostic et al , 2012) relating to impaired motor program adjustments and loss of automaticity (Hallett, 2008, Vandenbossche et al , 2012 as observed in freezers. Congruently, interference of freezers with a second cognitive task was described as an effective procedure to provoke freezing events given the susceptibility of freezers to 'cortical processing conflicts' and 'capacity overloads' (Peterson et al , 2014a, Spildooren et al , 2010.…”