Coordination deficits during trunk-assisted reach-to-grasp movements in Parkinson's disease

The effects of exergames on upper extremity performance, trunk mobility, gait, balance, and cognition in Parkinson's disease: a randomized controlled study

BACKGROUND

In recent years, game-based exercises have been included more in the rehabilitation programs of Parkinson's disease (PD) patients and positive effects have been observed.

AIM

This study aims to investigate the effects of innovative games particularly designed for neurological patients on upper extremity performance, trunk mobility and cognition in patients with PD.

METHOD

Twenty-three patients were enrolled in this randomized controlled study and randomly allocated into two groups: Exergames Program (EP) and Conventional Exercise Program (CP). Both groups received supervised physiotherapy sessions for 3 days a week and 8 weeks in total (24 sessions). Each session lasted 1 h. Evaluations were applied before and after the treatment: 9-Hole Peg Test (9-HPT), Minnesota Manual Dexterity Test (MMDT), Trunk Impairment Scale (TIS), Montreal Cognitive Assessment (MoCA), Unified Parkinson's Disease Rating Scale (MDS-UPDRS), Timed Up and Go (TUG), Functional Reach Test (FRT), and Parkinson Disease Questionnaire (PDQ-39).

RESULTS

Twenty patients were included in the analysis because of the dropouts. Our findings showed that both groups improved significantly in 9-HPT dominant side, MMDT, TIS, MDS-UPDRS, TUG, FRT, and PDQ-39 (p < 0.05). MoCA scores of EP group improved significantly (p < 0.05) while CP group's did not (p > 0.05). It was found that EP group had better improvements in 9-HPT dominant side, MMDT turning test, and MoCA than CP group when the differences in the changes within the groups were compared (p < 0.05).

CONCLUSION

Game-based training can be a useful rehabilitation tool to improve upper extremities performance, trunk mobility, cognition, functional mobility, balance, and quality of life and may have superiority over conventional exercises in improving cognition and upper extremity functions.

CLINICAL TRIAL NUMBER

NCT05235880. Release Date: April 1, 2022.

Moving, fast and slow: behavioural insights into bradykinesia in Parkinson's disease

The debilitating symptoms of Parkinson's disease, including the hallmark slowness of movement, termed bradykinesia, were described more than 100 years ago. Despite significant advances in elucidating the genetic, molecular and neurobiological changes in Parkinson's disease, it remains conceptually unclear exactly why patients with Parkinson's disease move slowly. To address this, we summarize behavioural observations of movement slowness in Parkinson's disease and discuss these findings in a behavioural framework of optimal control. In this framework, agents optimize the time it takes to gather and harvest rewards by adapting their movement vigour according to the reward that is at stake and the effort that needs to be expended. Thus, slow movements can be favourable when the reward is deemed unappealing or the movement very costly. While reduced reward sensitivity, which makes patients less inclined to work for reward, has been reported in Parkinson's disease, this appears to be related mainly to motivational deficits (apathy) rather than bradykinesia. Increased effort sensitivity has been proposed to underlie movement slowness in Parkinson's disease. However, careful behavioural observations of bradykinesia are inconsistent with abnormal computations of effort costs due to accuracy constraints or movement energetic expenditure. These inconsistencies can be resolved when considering that a general disability to switch between stable and dynamic movement states can contribute to an abnormal composite effort cost related to movement in Parkinson's disease. This can account for paradoxical observations such as the abnormally slow relaxation of isometric contractions or difficulties in halting a movement in Parkinson's disease, both of which increase movement energy expenditure. A sound understanding of the abnormal behavioural computations mediating motor impairment in Parkinson's disease will be vital for linking them to their underlying neural dynamics in distributed brain networks and for grounding future experimental studies in well-defined behavioural frameworks.

Writing errors in primary progressive aphasia

Peripheral errors in writing, that is errors produced download the spelling, have been occasionally described in primary progressive aphasia (PPA), but the possibility that these errors might be a marker of parkinsonism associated to some subtypes of PPA has not been explored. We investigated whether errors of peripheral nature characterize the writing disorder in PPA when associated with parkinsonian signs (PSs). Subgroups of PPA without PSs and with PSs were studied. The proportion of the central and peripheral errors in writing words and pseudowords was calculated in each group. In writing words, central errors significantly exceeded peripheral errors in subgroups without PSs. The higher the number of peripheral errors, the higher the probability of presenting PSs. No relation emerged between any error and the Unified Parkinson's Disease Rating Scale, but both types of errors correlated with measures of cognitive ability. Peripheral errors emerge when PSs are associated with PPA and may be linked to a decay of the cognitive control on movement, possibly involving the right hemisphere. Peripheral errors have clinical relevance in PPA, to the extent that they may assume the significance of a marker of specific subtypes and can help to outline the specific clinical picture of individual patients.

Quantitative Assessment of Finger Movement Profile in a Visual-Motor Task Based on a Tablet Computer: The Application in Parkinson's Disease

BACKGROUND/OBJECTIVE

Easily applicable, quantitative assessment of movement is widely needed in various clinical settings, especially in the evaluation of Parkinson's disease (PD).

METHODS

We developed a highly repeatable tablet computer-based finger movement assessment system (FMAS) to record finger movement profile in a visual-motor task both in PD (n = 217) and healthy participants (n = 221).

RESULTS

We found age-related declines in finger movement performance among the healthy participants but not in PD patients with the FMAS. Significant differences in movement time (MT) and latency/MT ratio but not in latency were observed in PD patients as compared with healthy subjects (P < 0.000). Meanwhile, we identified the latency/MT ratio as the optimal parameter to differentiate PD from age-matched healthy subjects in an age-independent manner (cut-off 1.08 with corresponding AUC = 0.861). In addition, a significant correlation was found between finger movement parameters and the Hoehn and Yahr scale (H-Y scale), UPDRS III score and the duration of the disease in PD patients (P < 0.01).

CONCLUSION

It was suggested that the tablet computer-based evaluation of finger movement provided an easily applicable quantitative method to assess the conditions of PD patients.

Quantitative assessment of upper limb functional impairments in people with Parkinson's disease

BACKGROUND

In clinical routine, upper limb motor disorders of people with Parkinson's disease are commonly assessed using scale- or timed tests, but such tools are not fully suitable for providing detailed information about their type and magnitude. To partly overcome these limitations, the present study aims to quantitatively investigate upper limb functional impairments through quantitative analysis of the "hand-to-mouth" task.

METHODS

Twenty-five individuals with Parkinson's disease and 20 age-matched healthy individuals underwent a kinematic analysis of the hand-to-mouth task from which spatio-temporal and kinematic measures, including summary measures (Arm Variable Score and Arm Profile Score), were calculated and correlated with clinical scores (Hoehn & Yahr, H&Y and the Unified Parkinson Disease Rating Scale, UPDRS).

FINDINGS

The "hand-to-mouth" movement is significantly altered in individuals with Parkinson's disease, especially in terms of reduced velocity, reduced range of motion of elbow flexion-extension and deviation from a physiologic pattern (Arm Profile Score 12.8° vs. 10.1° of unaffected, P = 0.002). Significant moderate correlations were found between movement duration and UPDRS-III (rho = 0.478, P = 0.001) and between the Arm Profile Score and H&Y (rho = 0.481, P = 0.024) and UPDRS-III (rho = 0.326, P = 0.001).

INTERPRETATION

On the basis of such findings, we can state that the kinematic analysis of "hand-to-mouth" movement, and in particular the summary indexes, are suitable for easily representing upper limb movement alterations in people with Parkinson's disease, thus allowing the monitoring either of disease progression or effectiveness of pharmacologic and rehabilitative treatments.

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.

Scaling and coordination deficits during dynamic object manipulation in Parkinson's disease

The ability to reach for and dynamically manipulate objects in a dexterous fashion requires scaling and coordination of arm, hand, and fingertip forces during reach and grasp components of this behavior. The neural substrates underlying dynamic object manipulation are not well understood. Insight into the role of basal ganglia-thalamocortical circuits in object manipulation can come from the study of patients with Parkinson's disease (PD). We hypothesized that scaling and coordination aspects of motor control are differentially affected by this disorder. We asked 20 PD patients and 23 age-matched control subjects to reach for, grasp, and lift virtual objects along prescribed paths. The movements were subdivided into two types, intensive (scaling) and coordinative, by detecting their underlying self-similarity. PD patients off medication were significantly impaired relative to control subjects for both aspects of movement. Intensive deficits, reduced peak speed and aperture, were seen during the reach. Coordinative deficits were observed during the reach, namely, the relative position along the trajectory at which peak speed and aperture were achieved, and during the lift, when objects tilted with respect to the gravitational axis. These results suggest that basal ganglia-thalamocortical circuits may play an important role in fine motor coordination. Dopaminergic therapy significantly improved intensive but not coordinative aspects of movements. These findings are consistent with a framework in which tonic levels of dopamine in the dorsal striatum encode the energetic cost of a movement, thereby improving intensive or scaling aspects of movement. However, repletion of brain dopamine levels does not restore finely coordinated movement.