Tests of dorsolateral frontal function correlate with objective tests of postural stability in early to moderate stage Parkinson’s disease

Abstract

A substantial number of individuals with Parkinson’s disease who display impaired postural stability experience accelerated cognitive decline and an increased prevalence of dementia. To date, studies suggest that this relationship, believed to be due to involvement of nondopaminergic circuitry, occurs later in the disease process. Research has yet to adequately investigate this cognitive-posturomotor relationship especially when examining earlier disease states. To gain greater understanding of the relationship between postural stability and cognitive function/dysfunction we evaluated a more stringent, objective measure of postural stability (center of pressure displacement), and also more specific measures of cognition in twenty-two patients with early to moderate stage Parkinson’s disease. The magnitude of the center of pressure displacement in this cohort was negatively correlated with performance on tests known to activate dorsolateral frontal regions. Additionally, the postural stability item of the UPDRS exhibited poor correlation with the more objective measure of center of pressure displacement and all specific measures of cognition. These results may serve as rationale for a more thorough evaluation of postural stability and cognition especially in individuals with mild Parkinson’s disease. Greater understanding of the relationship between motor and cognitive processes in Parkinson’s disease will be critical for understanding the disease process and its potential therapeutic possibilities.

Associations Between Cognitive and Gait Performance During Single- and Dual-Task Walking in People With Parkinson Disease

“…33,34 Cognitive tests specific to prefrontal function have been significantly associated with postural stability in patients with early to moderate PD. 35 Thus, the associations between both stride length and walking speed and cognitive processing speed revealed in this study may potentially be accounted for by shared white matter networks connecting frontal and parietal regions, and the association between executive function and step width variability may be due to overlapping systems in the prefrontal cortex.…”

Effects of cognitive task on gait initiation in Parkinson disease: Evidence of motor prioritization?

“…Indeed, impaired executive function and attention are related to postural instability in PD [5]. Further, "dual tasking," or the simultaneous performance of motor and/or cognitive tasks, compounds decrements in motor and cognitive performance [6][7][8].…”

Factors contributing to postural instability in patients with idiopathic Parkinson’s disease

“…The connections between the dorsolateral prefrontal cortex and the basal ganglia are suggested to cause working memory deficits in people with IPD. 31 The authors suggested that postural stability in people with IPD may reduce as cognitive function declines; however, this study was a preliminary investigation and further research in this area is warranted.…”

“…In one study, Nocera, et al 31 investigated whether reduced function of the dorsolateral prefrontal area affected postural stability in people with mild to moderate stages of IPD (Hoehn and Yahr stages 1-2.5), by using the three selected tests for cognitive tasks to activate the dorsolateral prefrontal area (Digit Span Backward Subtest from Wechsler Memory Scale, Controlled Word Association Test, and Stroop Colour Word Test) and the Mini-Mental State Examination (MMSE) for general evaluation of the degree of cognition. The study demonstrated a significant, moderate negative correlation between COP displacement area and reduced cognitive ability (P,0.05).…”

“…10,11 Factors reported to contribute to or be associated with postural instability include deficits in anticipatory and reactive responses to perturbations, [12][13][14][15][16][17][18][19][20] impaired vestibular sensory input 21 and sensory-motor integration, [22][23][24][25][26] impaired kinesthesia in the axial muscles during active postural stability control, 27 rigidity and stiffness, 28,29 latency of polysynaptic spinal stretch reflexes, 30 and impaired cognition. 31,32 It would appear, therefore, that the postural instability seen in IPD may be of complex aetiology. 25,33,34 Although there are narrative reviews exploring the reasons for postural instability in IPD, 4,6,[34][35][36][37] to our knowledge, no systematic or critical review of studies investigating factors contributing to or associated with postural instability has been published.…”