Poor dopaminergic response of impaired dexterity in Parkinson's disease: Bradykinesia or limb kinetic apraxia?

Abstract

Patients with Parkinson's disease (PD) often show impaired manual dexterity even when being only minimally bradykinetic, suggesting that they may have limb kinetic apraxia (LKA), that is, a loss of fine motor skill not explained by elemental motor deficits. To explore this dissociation, we investigated the differential dopaminergic responsiveness of dexterity and bradykinesia in PD. Twelve patients with PD (4 women, age 64.4 +/- 8.3, mean + SD) and 12 matched healthy controls (64.8 +/- 8.9) were tested twice in ON vs. OFF and 1st vs. 2nd trial, respectively. A coin rotation (CR) task was applied to assess dexterity and a finger tapping (FT) task to assess bradykinesia. Performance was followed by video recording and analyzed by measuring the frequency of CR and FT during three 10-second periods. Statistical analysis was done by a mixed factorial design with group (PD vs. controls) as between-subject factor and medication (ON- vs. OFF-state or 1st vs. 2nd trial), task (FT vs. CR), and handedness (dominant vs. nondominant) as within-subject factors. In patients with PD, regardless of hand involved, dopaminergic treatment only mildly improved CR performance, in contrast to the strong increase in FT scores (up to the level of controls), as demonstrated by the significant triple interaction of the factors group, medication, and task (F(1,22) = 7.9, P = 0.01; eta(2) = 0.26). Furthermore, CR scores were considerably lower, both in OFF and ON, than in normal controls, pointing to a substantial impairment of dexterity in PD (P < 0.001). In conclusion, impaired manual dexterity showing significantly diminished response to dopaminergic treatment suggests that dextrous deficits in PD are related to LKA rather than bradykinesia.

Short and valid assessment of apraxia in Parkinson’s disease

“…Validity of AST in atypical parkinsonism remains to be established. In addition, the contribution of apraxia to poorer ADL performance in PD, as demonstrated herein and in earlier reports [6,9,10], might have consequences for occupational and physical therapy. For instance, integration of strategy training in non-demented PD, shown to be effective in apraxic stroke patients [22], may be an effective approach, needing further exploration.…”

“…IMA and LKA are frequently seen in atypical parkinsonisms, such as progressive supranuclear palsy (PSP), dementia with Lewy Bodies (DLB) and as a hallmark in corticobasal degeneration (CBD) [2]. Mild IMA may even occur in some patients with Parkinson’s disease (PD) [3,4,5,6,7] and LKA may be more common than previously thought [8,9,10]. …”

Use of Jebsen Taylor Hand Function Test in evaluating the hand dexterity in people with Parkinson's disease

“…This suggests that patients with PD are less efficient to perform daily hand functions. Previous studies showed fine manual dexterity deficits in buttoning, 28 coin rotation test 7 and Purdue Pegboard test 8 in individuals with PD.…”

“…progressive reduction in the size of written words. 6 Standardised test such as coin rotation test, 7 and Purdue Pegboard test 8 have been used to document functional deficits in PD patients. These tests can be completed in a short time but they only evaluate the fine hand dexterity and may not be related to daily hand function.…”

Upper-Limb Assessment in People with Parkinson Disease: Is It a Priority for Therapists, and Which Assessment Tools Are Used?

“…2 Upper-limb (UL) disorders including decreased speed and amplitude of movements, 3 difficulty in performing sequential tasks, 4 and disrupted execution of fine manipulative hand activities 5,6 can restrict the lives of people living with PD and affect performance of daily tasks, 7 leisure activities, 8 and self-care. 7 The goal of physiotherapy (PT) and occupational therapy (OT) management of people with PD is to improve functional activity.…”