Relearning of writing skills in Parkinson's disease: A literature review on influential factors and optimal strategies

Evaluation of a 3D-Printed Writing Assistive Device for People With Brain Injury

Three-dimensional-printed assistive devices hold promise for improving writing abilities, yet factors influencing device selection and their impact on satisfaction and effectiveness remain unclear, especially in adults, as they are typically tested on children. The aim of this article is to assess the efficacy and satisfaction with a writing assistive device at different angles among individuals with brain injury and explore device selection factors. Twenty-six participants with brain injuries selected their preferred device angle. Writing speed, quality, and satisfaction were recorded. Immediate speed improvements were significant at 5° and 30° (p = .006, .013, respectively). Satisfaction scores did not significantly differ among angles. Normotonia in elbow (p < .001; odds ratio: 3.403) and wrist (p ≤ .001; odds ratio: 2.695) muscles increased the likelihood of selecting the 5° device. Immediate speed improvements at specific angles highlight the influence of muscle normotonia on device selection, vital for tailored brain injury rehabilitation.

Psychometric Properties of Jebsen Taylor Hand Function Test in an Italian Population with Parkinson's Disease

BACKGROUND

Assessment of upper limb function is critical in the rehabilitation process of people with Parkinson's Disease (PD), and universally validated outcome measures are needed to allow comparisons across the practice. Moreover, the study of psychometric properties of the same tool on different clinical populations guarantees the possibility of reliably evaluating the same rehabilitation treatment in people with different clinical conditions.

AIM OF THE STUDY

The aim of this research was to evaluate the psychometric characteristics of the Italian adaptation of the Jebsen Taylor Hand Function Test (JTHFT) in individuals with PD.

METHODS

The reliability and validity of the test were assessed in accordance with international standards. Internal consistency was measured using Cronbach's alpha, and test-retest reliability was determined via the intraclass correlation coefficient (ICC). The construct validity and cross-cultural validity of the test were evaluated using Pearson's correlation coefficient with three assessment tools on upper limb function, independence, and quality of life, with hand grip power measured by a dynamometer and an Italian pangram. Finally, responsiveness after a one month of rehabilitation treatment was measured using the Wilcoxon rank test.

RESULTS

Fifty-two Italian people with PD were recruited. Cronbach's alpha values ranged from 0.556 (non-dominant hand) to 0.668 (dominant hand); ICC values ranged from 0.754 to 0.988. Construct validity showed that several statistically significant correlations were detected. Wilcoxon's test showed that the assessment tool can detect a change in this population after treatment.

CONCLUSIONS

The JTHFT is a reliable, valid, and respondent tool to evaluate the upper limb and hand functionalities in PD patients. It should be added to the toolkit for measuring upper limb performance in this population, adding value to clinical evaluation and ensuring comparable results for different clinical populations and different countries.

Rehabilitative interventions for impaired handwriting in people with Parkinson's disease: a scoping review

BACKGROUND

People with Parkinson's disease (PD) often complain about handwriting difficulties. Currently, there is no consensus on the rehabilitative treatment and outcome measures for handwriting rehabilitation in PD.

OBJECTIVES

This study aims to investigate evidence on handwriting rehabilitation in people with PD, examining characteristics of interventions and outcomes.

METHODS

A scoping review was conducted according to Arksey and O'Malley's framework and PRISMA-ScR List. We searched electronic databases of PubMed, Physiotherapy Evidence Database, Cochrane Central Register of Controlled Trials, and Embase since inception to January 2023. We included interventional studies assessing the effects of structured rehabilitation programs for impaired handwriting in people with PD. Two reviewers independently selected studies, extracted data, and assessed the risk of bias using the Cochrane Collaboration's tool for assessing Risk of Bias version 2 or the Risk Of Bias In Non-randomized Studies. We performed a narrative analysis on training characteristics and assessed outcomes.

RESULTS

We included eight studies. The risk of bias was generally high. Either handwriting-specific or handwriting-non-specific trainings were proposed, and most studies provided a home-based training. Handwriting-specific training improved writing amplitude while handwriting-non-specific trainings, such as resistance and stretching/relaxation programs, resulted in increased writing speed.

CONCLUSIONS

The current knowledge is based on few and heterogeneous studies with high risk of bias. Handwriting-specific training might show potential benefits on handwriting in people with PD. Further high-quality randomized controlled trials are needed to reveal the effect of handwriting training in people with PD on standardized outcome measures. Handwriting-specific training could be combined to resistance training and stretching, which seemed to influence writing performance.

The accuracy of self-report logbooks of adherence to prescribed home-based exercise in Parkinson's disease

PURPOSE

This study compared self-report logbooks of exercise performance to objective measures of performance to determine the accuracy of and patterns of misreporting in self-report logbooks in people with Parkinson's disease.

MATERIALS AND METHODS

Fifteen participants from the intervention arm of a randomized control trial were prescribed a minimally supervised, 12-week, home-based upper limb exergame program (ACTRN 12614001048673). The exergame system provided an objective electronic measure of adherence for comparison with self-report logbooks.

RESULTS

Logbooks showed excellent to good accuracy of overall reported adherence to prescribed sessions (Intraclass correlation (ICC) = 0.83) and games (ICC 0.71). Logbooks were also a good to fair representation of weekly adherence across participants for both sessions (ICC 0.66) and games (ICC 0.56). Individual participant ICCs ranged from minimal to perfect agreement between logbooks and electronic records (ICC sessions range: -0.02 to 1; games range: -0.24 to 0.99). The pattern of logbook reporting suggested some participants were biasing entries to match prescribed exercise.

CONCLUSIONS

Self-report logbooks may provide an accurate measure of overall adherence. However, the accuracy of individual logbooks was highly variable indicating caution is needed in using self-report measures to assess individual adherence in intervention studies and for clinical decision making. Clinical Trial Registration: Registered in Australia and New Zealand Clinical Trials Registry (https://www.anzctr.org.au/): Registration number: ACTRN12614001048673.Implications for rehabilitationAdherence to prescribed unsupervised exercise is usually self-reported.Self-reported logbooks gave a good to excellent indication of exercise adherence overall when compared to electronically captured records for a group of participants with mild to moderate Parkinson's disease.There were high levels of variability in the accuracy of individual logbooks with a tendency to record prescribed rather than actual exercise.Logbooks may be accurate to monitor group adherence, but caution is required when using them to assess an individual's adherence to an exercise prescription.

Relating Global Cognition With Upper-Extremity Motor Skill Retention in Individuals With Mild-to-Moderate Parkinson's Disease

Background and Purpose: Cognition has been linked to rehabilitation outcomes in stroke populations, but this remains unexplored in individuals with Parkinson's disease (PD). The purpose of this secondary data analysis from a recent clinical trial (NCT02600858) was to determine if global cognition was related to skill performance after motor training in individuals with PD. Methods: Twenty-three participants with idiopathic PD completed 3 days of training on an upper-extremity task. For the purposes of the original clinical trial, participants trained either "on" or "off" their dopamine replacement medication. Baseline, training, and 48-h retention data have been previously published. Global cognition was evaluated using the Montreal Cognitive Assessment (MoCA). Linear regression examined whether MoCA score predicted longer-term retention at nine-day follow-up; baseline motor task performance, age, PD severity, depressive symptoms, and group (medication "on"/"off") were included as covariates. Baseline and follow-up motor task performance were assessed for all participants while "on" their medication. Results: MoCA score was positively related to follow-up motor task performance, such that individuals with better cognition were faster than those with poorer cognition. Baseline task performance, age, PD severity, depressive symptoms, and medication status were unrelated to follow-up performance. Discussion and Conclusions: Results of this secondary analysis align with previous work that suggest cognitive impairment may interfere with motor learning in PD and support the premise that cognitive training prior to or concurrent with motor training may enhance rehabilitative outcomes for individuals with PD. Findings also suggest that assessing cognition in individuals with PD could provide prognostic information about their responsiveness to motor rehabilitation.

Functional brain networks underlying automatic and controlled handwriting in Chinese

This study aimed to identify the functional brain networks underlying the distinctions between automatic and controlled handwriting in Chinese. Network-based analysis was applied to functional magnetic resonance imaging data collected while adult participants performed a copying task under automatic and speed-controlled conditions. We found significant differences between automatic and speed-controlled handwriting in functional connectivity within and between the frontoparietal network, default mode network, dorsal attention network, somatomotor network and visual network; these differences reflect the variations in general attentional control and task-relevant visuomotor operations. However, no differences in brain activation were detected between the two handwriting conditions, suggesting that the reorganization of functional networks, rather than the modulation of local brain activation, underlies the dissociations between automatic and controlled handwriting in Chinese. Our findings illustrate the brain basis of handwriting automaticity, shedding new light on how handwriting automaticity may be disrupted in individuals with neurological disorders.

Human Posture Detection Method Based on Wearable Devices

The dynamic detection of human motion is important, which is widely applied in the fields of motion state capture and rehabilitation engineering. In this study, based on multimodal information of surface electromyography (sEMG) signals of upper limb and triaxial acceleration and plantar pressure signals of lower limb, the effective virtual driving control and gait recognition methods were proposed. The effective way of wearable human posture detection was also constructed. Firstly, the moving average window and threshold comparison were used to segment the sEMG signals of the upper limb. The standard deviation and singular values of wavelet coefficients were extracted as the features. After the training and classification by optimized support vector machine (SVM) algorithm, the real-time detection and analysis of three virtual driving actions were performed. The average identification accuracy was 90.90%. Secondly, the mean, standard deviation, variance, and wavelet energy spectrum of triaxial acceleration were extracted, and these parameters were combined with plantar pressure as the gait features. The optimized SVM was selected for the gait identification, and the average accuracy was 90.48%. The experimental results showed that, through different combinations of wearable sensors on the upper and lower limbs, the motion posture information could be dynamically detected, which could be used in the design of virtual rehabilitation system and walking auxiliary system.

An improved sex-specific and age-dependent classification model for Parkinson's diagnosis using handwriting measurement

BACKGROUND AND OBJECTIVES

Diagnosis of Parkinson's with higher accuracy is always desirable to slow down the progression of the disease and improved quality of life. There are evidences of inherent neurological differences between male and females as well as between elderly and adults. However, the potential of such gender and age infomration have not been exploited yet for Parkinson's identification.

METHODS

In this paper, we develop a sex-specific and age-dependent classification method to diagnose the Parkinson's disease using the online handwriting recorded from individuals with Parkinson's (n = 37; m/f-19/18;age-69.3 ± 10.9yrs) and healthy controls (n = 38; m/f-20/18;age-62.4 ± 11.3yrs). A support vector machine ranking method is used to present the features specific to their dominance in sex and age group for Parkinson's diagnosis.

RESULTS

The sex-specific and age-dependent classifier was observed significantly outperforming the generalized classifier. An improved accuracy of 83.75% (SD = 1.63) with the female-specific classifier, and 79.55% (SD = 1.58) with the old-age dependent classifier was observed in comparison to 75.76% (SD = 1.17) accuracy with the generalized classifier.

CONCLUSIONS

Combining the age and sex information proved to be encouraging in classification. A distinct set of features were observed to be dominating for higher classification accuracy in a different category of classification.

Determinants of Dual-Task Training Effect Size in Parkinson Disease: Who Will Benefit Most?

BACKGROUND AND PURPOSE

Dual-task interventions show positive effects in people with Parkinson disease (PD), but it remains unclear which factors determine the size of these benefits. As a secondary analysis of the DUALITY trial, the aim of this study was to assess the determinants of the effect size after 2 types of dual-task practice.

METHODS

We randomly allocated 121 participants with PD to receive either integrated or consecutive dual-task training. Dual-task walking performance was assessed during (i) a backward digit span task (digit), (ii) an auditory Stroop task (Stroop), and (iii) a functional mobile phone task. Baseline descriptive, motor, and cognitive variables were correlated with the change in dual-task gait velocity after the intervention. Factors correlated with the change in dual-task gait velocity postintervention (P < 0.20) were entered into a stepwise forward multiple linear regression model.

RESULTS

Lower dual-task gait velocity and higher cognitive capacity (Scales for Outcomes in Parkinson's Disease-Cognition [ScopaCog]) at baseline were related to larger improvements in dual-task gait velocity after both integrated and consecutive dual-task training for all 3 tasks (β[gait] = -0.45, β[ScopaCog] = 0.34, R = 0.23, P < 0.001, for digit; β[gait] = -0.52, β[ScopaCog] = 0.29, R = 0.26, P < 0.001, for Stroop; and β[gait] = -0.40, β[ScopaCog] = 0.30, R = 0.18, P < 0.001, for mobile phone task).

DISCUSSION AND CONCLUSIONS

Participants with PD who showed a slow dual-task gait velocity and good cognitive functioning at baseline benefited most from the dual-task training, irrespective of the type of training and type of dual-task outcome.Video Abstract available for more insights from the authors (see Video, Supplemental Digital Content 1, available at: http://links.lww.com/JNPT/A242).

Training for Micrographia Alters Neural Connectivity in Parkinson's Disease

Despite recent advances in clarifying the neural networks underlying rehabilitation in Parkinson's disease (PD), the impact of prolonged motor learning interventions on brain connectivity in people with PD is currently unknown. Therefore, the objective of this study was to compare cortical network changes after 6 weeks of visually cued handwriting training (= experimental) with a placebo intervention to address micrographia, a common problem in PD. Twenty seven early Parkinson's patients on dopaminergic medication performed a pre-writing task in both the presence and absence of visual cues during behavioral tests and during fMRI. Subsequently, patients were randomized to the experimental (N = 13) or placebo intervention (N = 14) both lasting 6 weeks, after which they underwent the same testing procedure. We used dynamic causal modeling to compare the neural network dynamics in both groups before and after training. Most importantly, intensive writing training propagated connectivity via the left hemispheric visuomotor stream to an increased coupling with the supplementary motor area, not witnessed in the placebo group. Training enhanced communication in the left visuomotor integration system in line with the learned visually steered training. Notably, this pattern was apparent irrespective of the presence of cues, suggesting transfer from cued to uncued handwriting. We conclude that in early PD intensive motor skill learning, which led to clinical improvement, alters cortical network functioning. We showed for the first time in a placebo-controlled design that it remains possible to enhance the drive to the supplementary motor area through motor learning.

Being on Target: Visual Information during Writing Affects Effective Connectivity in Parkinson's Disease

A common motor symptom of Parkinson's disease (PD) is micrographia, characterized by a decrease in writing amplitude. Despite the relevance of this impairment for activities of daily living, the underlying neural network abnormalities and the impact of cueing strategies on brain connectivity are unknown. Therefore, we investigated the effects of visual cues on visuomotor network interactions during handwriting in PD and healthy controls (HCs). Twenty-eight patients with early disease, ON dopaminergic medication, and 14 age-matched controls performed a pre-writing task with and without visual cues in the scanner. Patients displayed weaker right visuo-parietal coupling than controls, suggesting impaired visuomotor integration during writing. Surprisingly, cueing did not have the expected positive effects on writing performance. Patients and controls, however, did activate similar networks during cued and uncued writing. During cued writing, the stronger influence of both visual and motor areas on the left superior parietal lobe suggested that visual cueing induced greater visual steering. In the absence of cues, there was enhanced coupling between parietal and supplementary motor areas (SMA) in line with previous findings in HCs during uncued motor tasks. In conclusion, the present study showed that patients with PD, despite their compromised brain function, were able to shift neural networks similar to controls. However, it seemed that visual cues provided a greater accuracy constraint on handwriting rather than offering unequivocal beneficial effects. Altogether, the results suggest that the effectiveness of using compensatory neural networks through applying external stimuli is task dependent and may compromise motor control during writing.

Cueing for people with Parkinson's disease with freezing of gait: A narrative review of the state-of-the-art and novel perspectives

Freezing, which manifests during gait and other movements, is an incapacitating motor symptom experienced by many patients with Parkinson's disease (PD). In rehabilitation, auditory and visual cueing methods are commonly applied to evoke a more goal-directed type of motor control and, as such, reduce freezing severity in patients with PD. In this narrative review, we summarize the current evidence regarding the effects of external cueing in patients with PD with freezing of gait (FOG) and provide suggestions on how to further improve cueing effectiveness with emerging technological developments. For this paper, we reviewed 24 articles describing the assessment of the effects of cues in patients with FOG (n=354). Because these studies mostly involved quasi-experimental designs, no methodological analysis was undertaken. In general, the evidence suggests that cue-augmented training can reduce FOG severity, improve gait parameters and improve upper-limb movements immediately after training. However, findings were not univocal, and long-term consolidation and transfer of the effects appear to be hampered specifically in this subgroup. With the increasing use of wearable technology, new possibilities are allowing for adapting the cue type, cue content and dose of cues to the needs of individual patients, which may boost the clinical use and efficiency of cued training in PD patients with FOG.

A long-term self-managed handwriting intervention for people with Parkinson's disease: results from the control group of a phase II randomized controlled trial

OBJECTIVE

To report on the control group of a trial primarily designed to investigate exercise for improving mobility in people with Parkinson's disease (pwP). The control group undertook a handwriting intervention to control for attention and time spent practising a specific activity.

DESIGN

Secondary analysis of a two-arm parallel phase II randomized controlled trial with blind assessment.

SETTING

Community.

PARTICIPANTS

PwP able to walk ⩾100 m and with no contraindication to exercise were recruited from the Thames Valley, UK, and randomized (1:1) to exercise or handwriting, via a concealed computer-generated list.

INTERVENTION

Handwriting was undertaken at home and exercise in community facilities; both were delivered through workbooks with monthly support visits and involved practice for 1 hour, twice weekly, over a period of six months.

MAIN MEASURES

Handwriting was assessed, at baseline, 3, 6 and 12 months, using a pangram giving writing speed, amplitude (area) and progressive reduction in amplitude (ratio). The Movement Disorder Society (MDS)-Unified Parkinson's Disease Rating Scale (UPDRS) item 2.7 measured self-reported handwriting deficits.

RESULTS

In all, 105 pwP were recruited (analysed: n  = 51 handwriting, n  = 54 exercise). A total of 40 pwP adhered to the handwriting programme, most completing ⩾1 session/week. Moderate effects were found for amplitude (total area: d = 0.32; 95% confidence interval (CI): -0.11 to 0.7; P = 0.13) in favour of handwriting over a period of12 months; effects for writing speed and ratio parameters were small ≤0.11. Self-reported handwriting difficulties also favoured handwriting (UPDRS 2.7: odds ratio (OR) = 0.55; 95% CI: 0.34 to 0.91; P = 0.02). No adverse effects were reported.

CONCLUSION

PwP generally adhere to self-directed home handwriting which may provide benefit with minimal risk. Encouraging effects were found in writing amplitude and, moreover, perceived ability.

An interactive videogame for arm and hand exercise in people with Parkinson's disease: A randomized controlled trial

INTRODUCTION

People with Parkinson's disease (PD) have difficulty performing upper extremity (UE) activities. The aim of this study was to investigate if exergames targeting the UE improve arm and hand activities and impairments and to establish the acceptability and feasibility of these games in people with PD.

METHODS

Two tablet-based exergames were developed which were controlled with finger movements or unimanual whole arm movements. Participants with PD were randomized to an exergame (n = 19) or control (n = 19) group. The exergame group performed UE exergames at home, 3 times per week for 12 weeks. The primary outcome measure was the nine hole peg test. Secondary outcomes included measures of UE activities and impairments, including the tapping test [speed (taps/60s), and error (weighted error score/speed)].

RESULTS

There were no between group differences in the nine hole peg test, or in any secondary outcome measures except for the tapping test. Horizontal tapping test results showed that exergame participants improved their speed (mean difference = 10.9 taps/60s, p < 0.001) but increased error (mean difference = 0.03, p = 0.03) compared to the control group. Participants enjoyed the games and improved in their ability to play the games. There were no adverse events.

CONCLUSION

The UE exergames were acceptable and safe, but did not translate to improvement in functional activities. It is likely that the requirement of the games resulted in increased movement speed at the detriment of accuracy. The design of exergames should consider task specificity.

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.

Relearning of Writing Skills in Parkinson's Disease After Intensive Amplitude Training

BACKGROUND

Micrographia occurs in approximately 60% of people with Parkinson's disease (PD). Although handwriting is an important task in daily life, it is not clear whether relearning and consolidation (ie the solid storage in motor memory) of this skill is possible in PD. The objective was to conduct for the first time a controlled study into the effects of intensive motor learning to improve micrographia in PD.

METHODS

In this placebo-controlled study, 38 right-handed people with PD were randomized into 2 groups, receiving 1 of 2 equally time-intensive training programs (30 min/day, 5 days/week for 6 weeks). The experimental group (n = 18) performed amplitude training focused at improving writing size. The placebo group (n = 20) received stretch and relaxation exercises. Participants' writing skills were assessed using a touch-sensitive writing tablet and a pen-and-paper test, pre- and posttraining, and after a 6-week retention period. The primary outcome was change in amplitude during several tests of consolidation: (1) transfer, using trained and untrained sequences performed with and without target zones; and (2) automatization, using single- and dual-task sequences.

RESULTS

The group receiving amplitude training significantly improved in amplitude and variability of amplitude on the transfer and automatization task. Effect sizes varied between 7% and 17%, and these benefits were maintained after the 6-week retention period. Moreover, there was transfer to daily life writing.

CONCLUSIONS

These results show automatization, transfer, and retention of increased writing size (diminished micrographia) after intensive amplitude training, indicating that consolidation of motor learning is possible in PD. © 2016 International Parkinson and Movement Disorder Society.

Micrographia, much beyond the writer's hand

INTRODUCTION

This review on micrographia aims to draw the clinician's attention to non-Parkinsonian etiologies, provide clues to differential diagnosis, and summarize current knowledge on the phenomenology, etiology, and mechanisms underlying micrographia.

METHODS

A systematic review of the existing literature was performed.

RESULTS

Micrographia, namely small sized handwriting has long been attributed to Parkinson's disease. However, it has often been observed as part of the clinical picture of additional neurodegenerative disorders, sometimes antedating the motor signs, or following focal basal ganglia lesions without any accompanying parkinsonism, suggesting that bradykinesia and rigidity are not sine-qua-non for the development of this phenomenon. Therefore, micrographia in a patient with no signs of parkinsonism may prompt the clinician to perform imaging in order to exclude a focal basal ganglia lesion. Dopaminergic etiology in this and other cases is doubtful, since levodopa ameliorates letter stroke size only partially, and only in some patients. Parkinsonian handwriting is often characterized by lack of fluency, slowness, and less frequently by micrographia. Deviations from kinematic laws of motion that govern normal movement, including the lack of movement smoothness and inability to scale movement amplitude to the desired size, may reflect impairments in motion planning, possible loss of automaticity and reduced movement vigor.

CONCLUSIONS

The etiology, neuroanatomy, mechanisms and models of micrographia are discussed. Dysfunction of the basal ganglia circuitry induced by neurodegeneration or disruption by focal damage give rise to micrographia.

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.

Neural correlates underlying micrographia in Parkinson's disease

Micrographia is a common symptom in Parkinson's disease, which manifests as either a consistent or progressive reduction in the size of handwriting or both. Neural correlates underlying micrographia remain unclear. We used functional magnetic resonance imaging to investigate micrographia-related neural activity and connectivity modulations. In addition, the effect of attention and dopaminergic administration on micrographia was examined. We found that consistent micrographia was associated with decreased activity and connectivity in the basal ganglia motor circuit; while progressive micrographia was related to the dysfunction of basal ganglia motor circuit together with disconnections between the rostral supplementary motor area, rostral cingulate motor area and cerebellum. Attention significantly improved both consistent and progressive micrographia, accompanied by recruitment of anterior putamen and dorsolateral prefrontal cortex. Levodopa improved consistent micrographia accompanied by increased activity and connectivity in the basal ganglia motor circuit, but had no effect on progressive micrographia. Our findings suggest that consistent micrographia is related to dysfunction of the basal ganglia motor circuit; while dysfunction of the basal ganglia motor circuit and disconnection between the rostral supplementary motor area, rostral cingulate motor area and cerebellum likely contributes to progressive micrographia. Attention improves both types of micrographia by recruiting additional brain networks. Levodopa improves consistent micrographia by restoring the function of the basal ganglia motor circuit, but does not improve progressive micrographia, probably because of failure to repair the disconnected networks.

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.

Motor automaticity in Parkinson's disease

Bradykinesia is the most important feature contributing to motor difficulties in Parkinson's disease (PD). However, the pathophysiology underlying bradykinesia is not fully understood. One important aspect is that PD patients have difficulty in performing learned motor skills automatically, but this problem has been generally overlooked. Here we review motor automaticity associated motor deficits in PD, such as reduced arm swing, decreased stride length, freezing of gait, micrographia and reduced facial expression. Recent neuroimaging studies have revealed some neural mechanisms underlying impaired motor automaticity in PD, including less efficient neural coding of movement, failure to shift automated motor skills to the sensorimotor striatum, instability of the automatic mode within the striatum, and use of attentional control and/or compensatory efforts to execute movements usually performed automatically in healthy people. PD patients lose previously acquired automatic skills due to their impaired sensorimotor striatum, and have difficulty in acquiring new automatic skills or restoring lost motor skills. More investigations on the pathophysiology of motor automaticity, the effect of L-dopa or surgical treatments on automaticity, and the potential role of using measures of automaticity in early diagnosis of PD would be valuable.

Analysis of in-air movement in handwriting: A novel marker for Parkinson's disease

BACKGROUND AND OBJECTIVE

Parkinson's disease (PD) is the second most common neurodegenerative disease affecting significant portion of elderly population. One of the most frequent hallmarks and usually also the first manifestation of PD is deterioration of handwriting characterized by micrographia and changes in kinematics of handwriting. There is no objective quantitative method of clinical diagnosis of PD. It is thought that PD can only be definitively diagnosed at postmortem, which further highlights the complexities of diagnosis.

METHODS

We exploit the fact that movement during handwriting of a text consists not only from the on-surface movements of the hand, but also from the in-air trajectories performed when the hand moves in the air from one stroke to the next. We used a digitizing tablet to assess both in-air and on-surface kinematic variables during handwriting of a sentence in 37 PD patients on medication and 38 age- and gender-matched healthy controls.

RESULTS

By applying feature selection algorithms and support vector machine learning methods to separate PD patients from healthy controls, we demonstrated that assessing the in-air/on-surface hand movements led to accurate classifications in 84% and 78% of subjects, respectively. Combining both modalities improved the accuracy by another 1% over the evaluation of in-air features alone and provided medically relevant diagnosis with 85.61% prediction accuracy.

CONCLUSIONS

Assessment of in-air movements during handwriting has a major impact on disease classification accuracy. This study confirms that handwriting can be used as a marker for PD and can be with advance used in decision support systems for differential diagnosis of PD.

Decision support framework for Parkinson's disease based on novel handwriting markers

Parkinson's disease (PD) is a neurodegenerative disorder which impairs motor skills, speech, and other functions such as behavior, mood, and cognitive processes. One of the most typical clinical hallmarks of PD is handwriting deterioration, usually the first manifestation of PD. The aim of this study is twofold: (a) to find a subset of handwriting features suitable for identifying subjects with PD and (b) to build a predictive model to efficiently diagnose PD. We collected handwriting samples from 37 medicated PD patients and 38 age- and sex-matched controls. The handwriting samples were collected during seven tasks such as writing a syllable, word, or sentence. Every sample was used to extract the handwriting measures. In addition to conventional kinematic and spatio-temporal handwriting measures, we also computed novel handwriting measures based on entropy, signal energy, and empirical mode decomposition of the handwriting signals. The selected features were fed to the support vector machine classifier with radial Gaussian kernel for automated diagnosis. The accuracy of the classification of PD was as high as 88.13%, with the highest values of sensitivity and specificity equal to 89.47% and 91.89%, respectively. Handwriting may be a valuable marker as a diagnostic and screening tool.