Force coordination during bimanual task performance in Parkinson's disease

Impaired Hand Function and Its Association With Self-Perceived Hand Functional Ability and Quality of Life in Parkinson Disease

OBJECTIVE

Comprehensive hand function in people with Parkinson disease (PD) has been underevaluated. The objectives were to compare self-perceived and objective hand functions of PD and controls, compare outcomes between more and less affected hand subgroups, and evaluate relationship between self-perceived and objective outcomes in subgroups.

DESIGN

A total of 165 PD and 82 healthy participants completed the Jebsen-Taylor Hand Function Test, Purdue Pegboard Test, grip strength test, and Manual Ability Measure-16 in a cross-sectional study. PD participants completed the Parkinson Disease Questionnaire-39. Associations between objective and self-perceived/quality of life outcomes in PD groups were analyzed, and nondominant and dominant more affected subgroups performance was compared.

RESULTS

PD participants had significantly worse performance in most Jebsen-Taylor Hand Function Test and all Purdue Pegboard Test items, lower Manual Ability Measure-16 scores, and poorer handgrip strength. Weak associations were found between dexterity, but not grip strength, and self-perceived functional hand ability and Parkinson Disease Questionnaire-39 scores in PD subgroups. For nondominant more affected subgroup, poorer dexterity was associated with better Parkinson Disease Questionnaire-39 Activity of Daily Living domain scores.

CONCLUSION

People with mild to moderate PD were shown to have poorer manual dexterity, reduced grip strength, and lower self-perceived functional hand ability than controls. Associations between dexterity and self-perceived outcomes highlight the importance of unimanual and bimanual training.

High intensity aerobic exercise improves bimanual coordination of grasping forces in Parkinson's disease

INTRODUCTION

Parkinson's disease (PD) disrupts the control and coordination of grasping forces, likely due to a disruption in basal ganglia circuitry and diminished activity within the supplementary motor area (SMA). High intensity aerobic exercise has been shown to enhance connectivity between basal ganglia nuclei and cortical areas, including the SMA. The aim of this project was to determine the effects of high intensity lower extremity exercise on motor control patterns underlying a manual dexterity task.

METHODS

PD participants completed eight weeks of high intensity aerobic exercise under forced or voluntary exercise (FE or VE) modalities. Grasping forces for each limb were quantified during a functional bimanual dexterity task. Data were collected while OFF antiparkinsonian medication at baseline, end of treatment (EOT), and eight weeks after exercise cessation (EOT+8).

RESULTS

Eight weeks of high intensity exercise improved MDS-UPDRS Motor III clinical ratings by more than 4 points (~15%) for the FE and VE groups. Time to complete the task decreased nearly 30% across both groups as well. The control and coordination of grasping forces, simultaneity of force initiation, and rate of grip and load force exhibited significant improvements following exercise. In general, improvements in biomechanical outcomes were sustained following exercise cessation.

CONCLUSION

High intensity aerobic exercise, achieved via a forced or voluntary mode, improved PD symptoms and bimanual dexterity. Sustained improvement of upper extremity motor control following exercise cessation indicates high intensity exercise enhances CNS functioning and suggests exercise may be a candidate for altering PD progression.

High intensity aerobic exercise improves information processing and motor performance in individuals with Parkinson's disease

Parkinson's disease (PD) adversely affects information processing and motor performance. The impact of aerobic exercise on modifying the deleterious effects of PD underlying information and motor control processes is not well established. The primary aim of this project was to determine the effects of an 8-week high intensity exercise intervention on information processing and movement execution in individuals with PD. A secondary aim sought to understand the effects of antiparkinsonian medication relative to exercise on motor control processes. Data were collected at baseline (on- and off-medication) and upon completion of the exercise intervention (off-medication). Information processing and motor execution were evaluated via simple and choice reaction time paradigms (SRT and CRT) performed on a mobile device. Neither exercise nor medication impacted information processing or movement execution under the SRT paradigm. However, under CRT, exercise improved movement execution and information processing: total time was significantly reduced from 814 to 747 ms (p < 0.001), reaction time improved from 543 to 502 ms (p < 0.001), movement time improved from 270 to 246 ms (p = 0.01), and movement velocity improved from 28 cm/sec to 30 cm/sec (p = 0.01). Improvements in total time and reaction time in the CRT paradigm persisted 4 and 8 weeks following exercise cessation. Antiparkinsonian medication improved motor execution, but not information processing. The improvement in information processing following aerobic exercise, but not levodopa administration, suggests high intensity exercise may be enhancing neural processing and non-motor pathways outside those impacted by medication. The persistence of symptom improvement despite exercise intervention cessation indicates exercise is a candidate for disease modification. Trial registration: The trial was first registered at ClinicalTrials.gov on 7/10/2012 under registration number NCT01636297.

Progressive muscle-strength protocol for the functionality of upper limbs and quality of life in individuals with Parkinson's disease: Pilot study

The effects of physical-therapy intervention on the motor function of upper limbs and the quality of life in patients with Parkinson's disease (PD) are not fully understood. We evaluated the effects of a progressive muscle-strengthening protocol for upper limbs on the functionality and quality of life. Patients were divided into two groups: Intervention (n = 6) and Control (n = 7). Assessment tools used were: Unified Parkinson's Disease Rating Scale (UPDRS), Parkinson's Disease Questionnaire, Nine-Hole Peg Test (9HPT), Test d'Évaluation des Membres Supérieurs de Personnes Âgées (TEMPA), 10-Repetition Maximum (10-RM) and handgrip dynamometer, which were applied pre- and post-intervention, with follow-up for one month after the last training session. Only, the Intervention group (post-intervention) showed significant statistical differences, with the following outcomes: UPDRS III (p = 0.042); 9HPT, right (p = 0.028) and left side (p = 0.028); TEMPA for total right side (p = 0.028), left side (p = 0.028) and total bilateral tasks (p = 0.028); TEMPA task 2 - open a jar and take a spoonful of coffee (p = 0.028), task 3 - pick up a pitcher and pour water into a glass for right (p = 0.046) and left side (p = 0.028), task 5 - write on an envelope and stick on a stamp (p = 0.028), and task 6 - shuffle and deal playing cards (p = 0.028). We observed significant statistical differences between groups (post-intervention) for TEMPA task 6 (p = 0.032), total right side (p = 0.032), and total bilateral tasks (p = 0.032). An increase in the maximum load in the post-intervention stage, based on the 10-RM test, was observed on the right (p = 0.003) and left (p = 0.007) sides. Our results showed an improvement in upper-limb functionality in PD patients submitted to progressive muscle-strength training, although not in quality of life.

Prehension synergies and hand function in early-stage Parkinson's disease

We explored the multi-digit synergies and hand performance in object manipulations and pressing tasks in patients with early-stage Parkinson's disease (PD) and healthy controls. Synergies were defined as inter-trials co-variation patterns among forces/moments produced by individual digits that stabilized a resultant mechanical variable. The subjects performed three main tasks: pressing (steady-state force production followed by a force pulse into the target), prehension (manipulation of a handheld instrumented handle imitating the action of taking a sip from a glass), and functional object manipulation (moving a glass with water as quickly and accurately as possible along a chain of targets). The PD patients were slower compared to controls in all three tasks. Patients showed smaller synergy indices in the pressing and prehension tasks. In the prehension tasks, patients showed elevated grip force at steady states with smaller grip force modulation during the handle motion. PD patients showed smaller feed-forward synergy adjustments in preparation to the quick action in the pressing and (to a smaller degree) prehension tasks. Synergy indices correlated with the time index of performance in the functional glass-with-water task, whereas none of the indices correlated with the Unified PD Rating Scale part III-motor scores. We interpret the results as pointing at an important role of subcortical structures in motor synergies and their feed-forward adjustments to action.

Impaired Object Handling during Bimanual Task Performance in Multiple Sclerosis

We investigated the kinetic features of manual dexterity and fine motor control during a task that resembles an activity of daily living in 30 persons with relapsing-remitting multiple sclerosis (PwMS). Specifically, a novel two-transducer system was used to measure time and grip-load forces during a bimanual task that is similar to opening and closing a jar. We hypothesized that PwMS would have increased grip force production, deteriorations in kinetic timing, and preserved grip-load coupling indices compared to healthy controls (i.e., young and older adults). Increased grip force production and deterioration in timing indices were confirmed in PwMS. Abnormal grip-load coupling was exhibited by PwMS, in contrast to healthy participants. The correlation between task time and self-reported disability scores suggests that objective measurement of impaired upper-extremity movements relates to perception of overall function.

Bimanual force coordination in Parkinson's disease patients with bilateral subthalamic deep brain stimulation

OBJECTIVE

Studies of bimanual actions similar to activities of daily living (ADLs) are currently lacking in evaluating fine motor control in Parkinson's disease patients implanted with bilateral subthalamic deep brain stimulators. We investigated basic time and force characteristics of a bimanual task that resembles performance of ADLs in a group of bilateral subthalamic deep brain stimulation (DBS) patients.

METHODS

Patients were evaluated in three different DBS parameter conditions off stimulation, on clinically derived stimulation parameters, and on settings derived from a patient-specific computational model. Model-based parameters were computed as a means to minimize spread of current to non-motor regions of the subthalamic nucleus via Cicerone Deep Brain Stimulation software. Patients were evaluated off parkinsonian medications in each stimulation condition.

RESULTS

The data indicate that DBS parameter state does not affect most aspects of fine motor control in ADL-like tasks; however, features such as increased grip force and grip symmetry varied with the stimulation state. In the absence of DBS parameters, patients exhibited significant grip force asymmetry. Overall UPDRS-III and UPDRS-III scores associated with hand function were lower while patients were experiencing clinically-derived or model-based parameters, as compared to the off-stimulation condition.

CONCLUSION

While bilateral subthalamic DBS has been shown to alleviate gross motor dysfunction, our results indicate that DBS may not provide the same magnitude of benefit to fine motor coordination.