tDCS-Enhanced Consolidation of Writing Skills and Its Associations With Cortical Excitability in Parkinson Disease: A Pilot Study

Background. Learning processes of writing skills involve the re-engagement of previously established motor programs affected by Parkinson disease (PD). To counteract the known problems with consolidation in PD, transcranial direct current stimulation (tDCS) could be imperative to achieve a lasting regeneration of habitual motor skills. Objective. To examine tDCS-enhanced learning of writing and explore alterations in cortical excitability after stimulation in PD compared with healthy controls (HCs). Methods. Ten patients and 10 HCs received 2 training sessions combined with 20 minutes of 1-mA anodal tDCS or sham on the left primary motor cortex in a randomized crossover design. Writing skills on a tablet and paper were assessed at baseline, after training, and after 1 week of follow-up. Before and immediately after the intervention, cortical excitability and inhibition were measured during rest and activity. Results. Writing amplitude and velocity improved when practice was tDCS supplemented compared with sham in PD. Benefits were sustained at retention for trained and untrained tasks on the tablet as well as for writing on paper. No improvements were found for HCs. Reduced resting motor thresholds after tDCS indicated tDCS-enhanced cortical excitability. Additionally, increments in motor-evoked potential amplitudes correlated with improved writing in PD, whereas HCs showed the opposite pattern. Conclusion. Our results endorse the usefulness of tDCS-boosted learning in PD, at least when applied to improving writing capacity. Although further confirmatory studies are needed, these novel findings are striking because tDCS-mediated consolidation was found for learning a motor task directly affected by PD.status: publishe

Handwriting impairments in people with Parkinson’s disease and freezing of gait

BACKGROUND: Recent studies show that patients with Parkinson's disease (PD) and freezing of gait (FOG) experience motor problems outside their gait freezing episodes. Because handwriting is also a sequential movement, it may be affected in PD patients with FOG relative to those without. OBJECTIVE: The current study aimed to assess the quality of writing in PD patients with and without FOG in comparison to healthy controls (CTs) during various writing tasks. METHODS: Handwriting was assessed by the writing of cursive loops on a touch-sensitive writing tablet and by means of the Systematic Screening of Handwriting Difficulties (SOS) test in 30 PD patients with and without freezing and 15 healthy age-matched CTs. The tablet tests were performed at 2 different sizes, either continuously or alternatingly, as indicated by visual target lines. RESULTS: Patients with freezing showed decreased writing amplitudes and increased variability compared with CTs and patients without freezing on the writing tablet tests. Writing problems were present during both tests but were more pronounced during writing at alternating compared with writing at continuous size. Patients with freezing also had a higher total score on the SOS test than patients without freezing and CTs, reflecting more extensive handwriting problems, particularly with writing fluency. CONCLUSIONS: Writing is more severely affected in PD patients with FOG than in those without FOG. These results indicate that deficient movement sequencing and adaptation is a generic problem in patients with FOG.status: publishe

Impaired Retention of Motor Learning of Writing Skills in Patients with Parkinson’s Disease with Freezing of Gait

BACKGROUND: Patients with Parkinson's disease (PD) and freezing of gait (FOG) suffer from more impaired motor and cognitive functioning than their non-freezing counterparts. This underlies an even higher need for targeted rehabilitation programs in this group. However, so far it is unclear whether FOG affects the ability for consolidation and generalization of motor learning and thus the efficacy of rehabilitation. OBJECTIVE: To investigate the hallmarks of motor learning in people with FOG compared to those without by comparing the effects of an intensive motor learning program to improve handwriting. METHODS: Thirty five patients with PD, including 19 without and 16 with FOG received six weeks of handwriting training consisting of exercises provided on paper and on a touch-sensitive writing tablet. Writing training was based on single- and dual-task writing and was supported by means of visual target zones. To investigate automatization, generalization and retention of learning, writing performance was assessed before and after training in the presence and absence of cues and dual tasking and after a six-week retention period. Writing amplitude was measured as primary outcome measure and variability of writing and dual-task accuracy as secondary outcomes. RESULTS: Significant learning effects were present on all outcome measures in both groups, both for writing under single- and dual-task conditions. However, the gains in writing amplitude were not retained after a retention period of six weeks without training in the patient group without FOG. Furthermore, patients with FOG were highly dependent on the visual target zones, reflecting reduced generalization of learning in this group. CONCLUSIONS: Although short-term learning effects were present in both groups, generalization and retention of motor learning were specifically impaired in patients with PD and FOG. The results of this study underscore the importance of individualized rehabilitation protocols.status: publishe

Altered effective connectivity contributes to micrographia in patients with Parkinson's disease and freezing of gait

Recently, it was shown that patients with Parkinson's disease (PD) and freezing of gait (FOG) can also experience freezing episodes during handwriting and present writing problems outside these episodes. So far, the neural networks underlying increased handwriting problems in subjects with FOG are unclear. This study used dynamic causal modeling of fMRI data to investigate neural network dynamics underlying freezing-related handwriting problems and how these networks changed in response to visual cues. Twenty-seven non-freezers and ten freezers performed a pre-writing task with and without visual cues in the scanner with their right hand. The results showed that freezers and non-freezers were able to recruit networks involved in cued and uncued writing in a similar fashion. Whole group analysis also revealed a trend towards altered visuomotor integration in patients with FOG. Next, we controlled for differences in disease severity between both patient groups using a sensitivity analysis. For this, a subgroup of ten non-freezers matched for disease severity was selected by an independent researcher. This analysis further exposed significantly weaker coupling in mostly left hemispheric visuo-parietal, parietal - supplementary motor area, parietal - premotor, and premotor-M1 pathways in freezers compared to non-freezers, irrespective of cues. Correlation analyses revealed that these impairments in connectivity were related to writing amplitude and quality. Taken together, these findings show that freezers have reduced involvement of the supplementary motor area in the motor network, which explains the impaired writing amplitude regulation in this group. In addition, weaker supportive premotor connectivity may have contributed to micrographia in freezers, a pattern that was independent of cueing.status: publishe

Impaired Retention of Motor Learning of Writing Skills in Patients with Parkinson's Disease with Freezing of Gait.

BACKGROUND:Patients with Parkinson's disease (PD) and freezing of gait (FOG) suffer from more impaired motor and cognitive functioning than their non-freezing counterparts. This underlies an even higher need for targeted rehabilitation programs in this group. However, so far it is unclear whether FOG affects the ability for consolidation and generalization of motor learning and thus the efficacy of rehabilitation. OBJECTIVE:To investigate the hallmarks of motor learning in people with FOG compared to those without by comparing the effects of an intensive motor learning program to improve handwriting. METHODS:Thirty five patients with PD, including 19 without and 16 with FOG received six weeks of handwriting training consisting of exercises provided on paper and on a touch-sensitive writing tablet. Writing training was based on single- and dual-task writing and was supported by means of visual target zones. To investigate automatization, generalization and retention of learning, writing performance was assessed before and after training in the presence and absence of cues and dual tasking and after a six-week retention period. Writing amplitude was measured as primary outcome measure and variability of writing and dual-task accuracy as secondary outcomes. RESULTS:Significant learning effects were present on all outcome measures in both groups, both for writing under single- and dual-task conditions. However, the gains in writing amplitude were not retained after a retention period of six weeks without training in the patient group without FOG. Furthermore, patients with FOG were highly dependent on the visual target zones, reflecting reduced generalization of learning in this group. CONCLUSIONS:Although short-term learning effects were present in both groups, generalization and retention of motor learning were specifically impaired in patients with PD and FOG. The results of this study underscore the importance of individualized rehabilitation protocols

When motor control gets out of hand: speeding up triggers freezing in the upper limb in Parkinson’s disease

INTRODUCTION: Patients with Parkinson's disease (PD) can suffer from sudden movement arrests during upper limb tasks. The current study investigated a test to assess freezing of the upper limbs (FOUL) at two speed conditions to improve the sensitivity of FOUL detection. METHODS: Forty-nine patients with PD and 10 age-matched controls (HC) performed a freezing-provoking writing task, requiring up- and down-stroke writing at varying sizes in-between visual target zones indicating funnel-shapes on a touch-sensitive tablet. They performed five trials at their preferred speed, referred to as the Normal Funnel Task (NFT) and five trials at maximum speed, referred to as the Fast Funnel Task (FFT), in a random order. RESULTS: Based on a combination of kinematic criteria and video analysis, 183 FOUL episodes were detected in 24 participants (23 PD, 1 HC). The number of patients with FOUL, number of FOUL episodes and percentage time frozen were significantly higher during FFT than NFT. Most FOUL episodes occurred during writing at small (51.6%) and decreasing size (36.3%). Additionally, FOUL outcomes significantly correlated with the Montreal Cognitive Assessment and New Freezing of Gait Questionnaire. CONCLUSION: As FOUL is more prevalent under higher task demands, these data offer support for the "threshold model", previously proposed to provide insight in freezing of gait (FOG) and underscoring the presupposed link between FOG and FOUL. As well, this study may provide a novel paradigm to assess FOUL in both laboratory and clinical settings.status: Published onlin

Samen evalueren met de doelgroep: lessen uit de ontwikkeling van een participatief evaluatie-instrument

Samenvatting: Bij het evalueren van gezondheidsbevordering is het van belang de beoogde doelgroep erbij te betrekken. In de praktijk wordt participatieve evaluatie echter nog onvoldoende ingezet. Om professionals te helpen de doelgroep bij de evaluatie te betrekken werd hiervoor in het kader van de JOGG-aanpak (Gezonde Jeugd, Gezonde Toekomst, voorheen: Jongeren Op Gezond Gewicht) een instrument ontwikkeld. Hoewel het samen met de JOGG-professionals is ontwikkeld, bleek dit instrument niet goed aan te sluiten bij hun behoeften. In dit artikel reflecteren we op hoe dit komt en delen we de geleerde lessen. Ongelijkwaardige samenwerking tussen onderzoekers en professionals heeft er aan bijgedragen dat praktijkbehoeften onvoldoende in het evaluatie-instrument zijn meegenomen. Daarnaast ervaren professionals zelf verschillende uitdagingen bij participatieve evaluatie, omdat de context waarin zij werken hen hierin onvoldoende faciliteert. Abstract: Participation of the target group is important in evaluating health promotion. However, in practice the use of participatory evaluation is still limited. To support professionals within the JOGG (Healthy Youth, Healthy Future, previously Youth At a Healthy Weight) rogramme with participatory evaluation a tool was developed. Although this tool was developed with professionals, it did not meet their needs. In this article we reflect on the development of the tool and share lessons learned. Unequal collaboration between researchers and professionals may have contributed to the needs of professionals being insufficiently taken into account. Additionally, professionals themselves experience challenges with participatory evaluation, because the context in which they work does not facilitate participatory evaluation

Opposite effects of visual cueing during writing-like movements of different amplitudes in Parkinson's disease

BACKGROUND: Handwriting is often impaired in Parkinson's disease (PD). Several studies have shown that writing in PD benefits from the use of cues. However, this was typically studied with writing and drawing sizes that are usually not used in daily life. OBJECTIVE: This study examines the effect of visual cueing on a prewriting task at small amplitudes (≤1.0 cm) in PD patients and healthy controls to better understand the working action of cueing for writing. METHODS: A total of 15 PD patients and 15 healthy, age-matched controls performed a prewriting task at 0.6 cm and 1.0 cm in the presence and absence of visual cues (target lines). Writing amplitude, variability of amplitude, and speed were chosen as dependent variables, measured using a newly developed touch-sensitive tablet. RESULTS: Cueing led to immediate improvements in writing size, variability of writing size, and speed in both groups in the 1.0 cm condition. However, when writing at 0.6 cm with cues, a decrease in writing size was apparent in both groups (P < .001) and the difference in variability of amplitude between cued and uncued writing disappeared. In addition, the writing speed of controls decreased when the cue was present. CONCLUSIONS: Visual target lines of 1.0 cm improved the writing of sequential loops in contrast to lines spaced at 0.6 cm. These results illustrate that, unlike for gait, visual cueing for fine-motor tasks requires a differentiated approach, taking into account the possible increases of accuracy constraints imposed by cueing.status: publishe

Transcranial direct current stimulation in Parkinson's disease: Neurophysiological mechanisms and behavioral effects

Recent research has highlighted the potential of transcranial direct current stimulation (tDCS) to complement rehabilitation effects in the elderly and in patients with neurological diseases, including Parkinson's disease (PD). TDCS can modulate cortical excitability and enhance neurophysiological mechanisms that compensate for impaired learning in PD. The objective of this systematic review is to provide an overview of the effects of tDCS on neurophysiological and behavioral outcome measures in PD patients, both as a stand-alone and as an adjunctive therapy. We systematically reviewed the literature published throughout the last 10 years. Ten studies were included, most of which were sham controlled. Results confirmed that tDCS applied to the motor cortex had significant results on motor function and to a lesser extent on cognitive tests. However, the physiological mechanism underlying the long-term effects of tDCS on cortical excitability in the PD brain are still unclear and need to be clarified in order to apply this technique optimally to a wider population in the different disease stages and with different medication profiles.publisher: Elsevier articletitle: Transcranial direct current stimulation in Parkinson's disease: Neurophysiological mechanisms and behavioral effects journaltitle: Neuroscience & Biobehavioral Reviews articlelink: http://dx.doi.org/10.1016/j.neubiorev.2015.08.010 content_type: article copyright: Copyright © 2015 Elsevier Ltd. All rights reserved.status: publishe