Abnormal interhemispheric inhibition in musician's dystonia – Trait or state?

IntroductionA clustering of relatives with dystonia has been reported in families with musician's dystonia suggesting a genetic contribution to this disease. The aim of the present study was to determine whether interhemispheric inhibition (IHI) measured with transcranial magnetic stimulation is impaired in healthy family members rendering it a suitable endophenotypic marker for musician's dystonia.MethodsPatients with musician's hand dystonia (n = 21), patients with sporadic writer's cramp (n = 15), their healthy family members (n = 27), healthy musicians (n = 12) and healthy non-musicians (n = 12) were included. An extended interview about the family history and musical activity was performed. IHI in both hemispheres was measured using transcranial magnetic stimulation.ResultsA stepwise regression analysis revealed musical activity (p = 0.001) and a family history of dystonia (p = 0.008) but not dystonia per se, age, handedness or gender as relevant factors modulating IHI.ConclusionThese data support the notion of a genetic background of musician's hand dystonia and suggests that reduced IHI is a possible endophenotypic marker of this disorder.     

Quantification of instability of tone production in embouchure dystonia

IntroductionMusician's dystonia is a task-specific loss of voluntary motor control of the fingers or the embouchure. In contrast to pianists' dystonia, which can be objectively assessed based on movement kinematics and muscular activities, no objective quantitative measure has been established for embouchure dystonia.MethodsWe focused on acoustic signals, and investigated, whether the fluctuation of the time-varying fundamental frequency of a note can provide an objective and reliable measure of embouchure dystonia.ResultsA comparison between patients with embouchure dystonia and healthy controls found a significantly higher variability of the fundamental frequency for the patients.ConclusionThe present findings propose a new quantification and objectivation method for embouchure dystonia.     

Defective inhibition and inter‐regional phase synchronization in pianists with musician's dystonia: An EEG study

Recent neurophysiological studies have associated focal‐task specific dystonia (FTSD) with impaired inhibitory function. However, it remains unknown whether FTSD also affects the inhibition (INH) of long‐term overlearned motor programs. Consequently, we investigated in a Go/NoGo paradigm the neural correlates associated with the activation (ACT) and inhibition of long‐term overlearned motor memory traces in pianists with musician's dystonia (MD), a form of FTSD, during a relevant motor task under constraint timing conditions with multichannel EEG. In NoGo trials, the movement related cortical potentials showed a positive shift after the NoGo signal related to inhibition and was significantly smaller over sensorimotor areas in musicians with MD. Further, we observed an increase at 850–900 ms in the power of beta oscillations which was significantly weaker for the patient group. The role of the inter‐electrode phase coupling in the sensorimotor integration of inhibitory processes turned out to be the most relevant physiological marker: the global phase synchronization during INH exhibited an increase between 230 and 330 ms and 7–8 Hz, increase which was significantly smaller for pianists with MD. This effect was due to a weaker phase synchronization between the supplementary motor cortex and left premotor and sensorimotor electrodes in patients. Thus, our findings support the hypothesis of a deficient phase coupling between the neuronal assemblies required to inhibit motor memory traces in patients with MD. EMG recorded from the right flexor pollicis longus muscle confirmed that patients with MD had a disrupted INH in NoGo trials. Hum Brain Mapp 2009. © 2008 Wiley‐Liss, Inc.     

Failure of cathodal direct current stimulation to improve fine motor control in musician's dystonia

Musician's dystonia (MD) is a task‐specific movement disorder with a loss of voluntary motor control in highly trained movements. Defective inhibition on different levels of the central nervous system is involved in its pathophysiology. Cathodal transcranial direct current stimulation (ctDCS) diminishes excitability of the motor cortex and improves performance in overlearned tasks in healthy subjects. The aim of this study was to investigate whether ctDCS improves fine motor control in MD. Professional guitarists (n = 10) with MD played exercises before, directly after ctDCS, and 60 min after ctDCS. ctDCS (2 mA, 20 min) was applied on the primary motor cortex contralateral to the affected hand. Guitar exercises were video‐documented and symptoms were evaluated by three independent experts. No beneficial effect of ctDCS on fine motor control was found for the entire group. However, motor control of one guitarist improved after stimulation. This patient suffered from arm dystonia, whereas the other guitarists suffered from hand dystonia. © 2009 Movement Disorder Society     

Reduced recruitment of motor association areas during bimanual coordination in concert pianists

Bimanual motor coordination is essential for piano playing. The functional neuronal substrate for high‐level bimanual performance achieved by professional pianists is unclear. We compared professional pianists to musically naïve controls while carrying out in‐phase (mirror) and anti‐phase (parallel) bimanual sequential finger movements during functional magnetic resonance imaging (fMRI). This task corresponds to bimanually playing scales practiced daily by pianists from the beginning of piano playing. Musicians and controls showed significantly different functional activation patterns. When comparing performance of parallel movements to rest, musically naïve controls showed stronger activations than did pianists within a network including anterior cingulate cortex, right dorsal premotor cortex, both cerebellar hemispheres, and right basal ganglia. The direct comparison of bimanual parallel to mirror movements between both groups revealed stronger signal increases in controls within mesial premotor cortex (SMA), bilateral cerebellar hemispheres and vermis, bilateral prefrontal cortex, left ventral premotor cortex, right anterior insula, and right basal ganglia. These findings suggest increased efficiency of cortical and subcortical systems for bimanual movement control in musicians. This may be fundamental to achieve high‐level motor skills allowing the musician to focus on artistic aspects of musical performance. Hum. Brain Mapping 22:206–215, 2004. © 2004 Wiley‐Liss, Inc.     

Transmodal sensorimotor networks during action observation in professional pianists

Audiovisual perception and imitation are essential for musical learning and skill acquisition. We compared professional pianists to musically naive controls with fMRI while observing piano playing finger-hand movements and serial finger-thumb opposition movements both with and without synchronous piano sound. Pianists showed stronger activations within a fronto-parieto-temporal network while observing piano playing compared to controls and contrasted to perception of serial finger-thumb opposition movements. Observation of silent piano playing additionally recruited auditory areas in pianists. Perception of piano sounds coupled with serial finger-thumb opposition movements evoked increased activation within the sensorimotor network. This indicates specialization of multimodal auditory-sensorimotor systems within a fronto-parieto-temporal network by professional musical training. Musical 'language,' which is acquired by observation and imitation, seems to be tightly coupled to this network in accord with an observation-execution system linking visual and auditory perception to motor performance.     

Quantification of focal dystonia in pianists using scale analysis.

Focal dystonia in pianists is a task-specific movement disorder that causes loss of pianistic skills and provokes irregularities in playing. So far, no method has been available for objective quantification of the disorder. Eight professional pianists with focal dystonia and eight healthy professional pianists matched by age, gender, and handedness were examined, using a newly developed MIDI-based Scale Analysis as well as the Arm Dystonia Disability Scale (ADDS). Key velocities and timing parameters were analyzed. In 5 pianists with dystonia, follow-up examinations were carried out after treatment with botulinum toxin-A. In affected hands, significantly higher mean standard deviations of timing parameters were seen compared with healthy reference hands. After treatment with botulinum toxin-A, significant improvements in performance parameters were monitored by Scale Analysis. Mean standard deviations of inter-onset intervals correlated with ADDS scores. We conclude that Scale Analysis is an effective and precise tool for quantification of focal dystonia in pianists and provides fine resolution. It is independent of rating methods and allows reliable follow-up examinations during treatment.     

Complexity and familiarity enhance single-trial detectability of imagined movements with electroencephalography

ObjectiveWe sought to determine whether the sensorimotor rhythms (SMR) elicited during motor imagery (MI) of complex and familiar actions could be more reliably detected with electroencephalography (EEG), and subsequently classified on a single-trial basis, than those elicited during relatively simpler imagined actions.MethodsGroups of healthy volunteers, including experienced pianists and ice hockey players, performed MI of varying complexity and familiarity. Their electroencephalograms were recorded and compared using brain-computer interface (BCI) approaches and spectral analyses.ResultsRelative to simple MI, significantly more participants produced classifiable SMR for complex MI. During MI of performance of a complex musical piece, the EEG of the experienced pianists was classified significantly more accurately than during MI of performance of a simpler musical piece. The accuracy of EEG classification was also significantly more sustained during complex MI.ConclusionMI of complex actions results in EEG responses that are more reliably classified for more individuals than MI of relatively simpler actions, and familiarity with actions enhances these responses in some cases.SignificanceThe accuracy of SMR-based BCIs in non-communicative patients may be improved by employing familiar and complex actions. Increased sensitivity to MI may also improve diagnostic accuracy for severely brain-injured patients in a vegetative state.     

Piano playing in Alzheimer's disease: Longitudinal study of a single case

Abstract

Preserved musical performance by patients with Alzheimer's disease (AD) has been attributed to an intact system for implicit musical cognition which may be localized in the right hemisphere. To examine this idea more thoroughly, we studied patient ML, a woman with AD who learned to play the piano as a child. Over three yearly evaluations, ML exhibited progressive deterioration in the following domains: language, visuospatial functions, attention, sequencing, picture priming, recognition of familiar songs, and discrimination of rhythm, meter, transposition, and major from minor keys, but pursuit rotor learning remained intact. By the third year of testing, ML also exhibited severe limb apraxia, but showed only subtle losses in the quality of her piano playing of familiar songs. She also showed immediate and accurate transfer of her playing skill from the piano to the xylophone. Preserved musical performance in AD seems to depend on circuits involving the basal ganglia, cerebellum and motor areas of the thalamus and cerebral cortex that remain relatively intact until the late stages of the disemse, but there is no evidence that the right hemisphere plays a special role in this phenomenon.     

Superior tactile performance and learning in professional pianists: evidence for meta-plasticity in musicians

Musician's brains constitute an interesting model for neuroplasticity. Imaging studies demonstrated that sensorimotor cortical representations are altered in musicians, which was assumed to arise from the development of skilled performance. However, the perceptual consequences of the cortical changes remain elusive. Here we ask whether cortical reorganization induced by professional musical skill training is paralleled by the evolution of other, unrelated perceptual abilities. We therefore studied psychophysically tactile spatial acuity as an indirect marker of cortical changes in professional pianists and non-musician control subjects using a simultaneous two-point discrimination paradigm. We show that long-lasting piano practising resulted in lower spatial discrimination thresholds in comparison to non-musicians. In musicians, individual discrimination thresholds were linearly correlated with the daily training duration, indicating a direct link between tactile acuity and the degree of piano practising. To investigate whether the superior acuity in pianists is subject to further improvement, we used a Hebbian stimulation protocol of tactile coactivation known to improve spatial tactile acuity. Three hours of coactivation further reduced their discrimination thresholds. The coactivation-induced gain in pianists was significantly larger in comparison to control subjects and correlated with the years of heavy daily practising (>3 h/day), but not with the total years including casual playing. Our results suggest that despite already high-level performance in pianists, Hebbian learning was more effective in musicians than in controls. This implies stronger capacities for plastic reorganization and points to enhanced learning abilities implicating a form of meta-plasticity in professional pianists.     

Phenotypic spectrum of musician's dystonia: A task‐specific disorder?

Background: Musician's dystonia (MD) is traditionally considered a sporadic and task‐specific movement disorder. Methods: The phenotypic spectrum of the disorder was studied in 116 patients suffering from MD including videotaping. Results: Based on the movement disorders observed, we categorized our patients into two different groups: (i) 65 patients with isolated MD, that is only present when playing the instrument and (ii) 51 patients with MD and one or more additional features of primary dystonia independent of MD (complex MD). Patients with a positive family history of movement disorders had an increased risk to develop complex MD [odds ratio = 4.80; 95% confidence interval: 1.94–11.92; P = 0.001]. Discussion: In previous studies, we recently identified 22 relatives with different types of movement disorders in the families of 28 MD patients. Taken together, our results further support a genetic contribution to MD with a broad individual and familial phenotypic spectrum consisting of MD, other dystonias and even other, non‐dystonic movement disorders. © 2010 Movement Disorder Society     

Impulsive and compulsive behaviors among Danish patients with Parkinson's disease: Prevalence,depression, and personality

IntroductionDopaminergic medication administered to ameliorate motor symptoms of Parkinson's disease is associated with impulse control disorders, such as pathological gambling, hypersexuality, compulsive buying, and binge eating. Studies indicate a prevalence of impulse control disorders in Parkinson's disease of 6–16%.ObjectiveTo estimate the prevalence of impulsive and compulsive behaviors among Danish patients with Parkinson's disease and to explore the relation of such behavioral disorders to depression and personality.Methods490 patients with Parkinson's disease (303 males), identified through the National Danish Patient Registry, were evaluated with: 1) the Questionnaire for Impulsive-Compulsive Disorders in Parkinson's Disease; 2) the Geriatric Depression Scale; and 3) the NEO-Personality Inventory.Results176 (35.9%) patients reported impulsive and compulsive behaviors sometime during Parkinson's disease (current symptoms in 73, 14.9%). Hereof, 114 (23.3%) reported multiple behavioral symptoms. Patients with behavioral symptoms were significantly younger, were younger at PD onset, had longer disease duration, displayed more motor symptoms, and received higher doses of dopaminergic medication than patients without behavioral symptoms. Furthermore, they reported significantly more depressive symptoms and scored significantly higher on neuroticism and lower on both agreeableness and conscientiousness than patients without behavioral symptoms.ConclusionA history of impulsive and compulsive behaviors are common in Danish patients with Parkinson's disease and have clinical correlates that may allow identification of patients at risk for developing these behaviors.     

An objective measure combining physical and cognitive fatigability: Correlation with subjective fatigue in Parkinson's disease

BackgroundObjective measures of physical and cognitive fatigability do not correlate with subjective Parkinson's disease (PD)-related fatigue. The relationship of subjective PD-related fatigue to tasks combining cognitive and motor effort has never been explored.MethodsForty-four right-handed, non-demented PD patients, 22 with (PD-F) and 22 without (PD-NF) fatigue, were tested using a sensor-engineered glove on their more affected hand. Patients performed sequential opposition finger movements following a metronome at 2 Hz for 5 min (cued task), and for another minute following a 2-min rest. The same task was repeated without sustained auditory cueing. Movement time (inter-tapping interval, ITI) and rate, touch duration, percentage of correct sequences and clinical measures (motor and fatigue severity, depression, sleep impairment and apathy) were analysed.ResultsIn the cued task, motor performance worsened over time (significantly increased ITI and decreased movement rate on the third to fifth minute) in PD-F patients only. In the uncued task, motor performance deteriorated similarly in the two groups. PD-F and PD-NF patients differed in ITI and movement rate deterioration over time only in the cued task, independently from motor severity, depression and sleep impairment. The severity of subjective fatigue complaints significantly correlated with motor performance deterioration in the cued task.ConclusionsPD-related fatigue is associated with performance on an externally cued, attention-controlled motor task, but not with an uncued version of the same task. The finding supports a link between PD-related fatigue and attention-demanding motor tasks, proposing a model of inducible fatigue applicable to future clinical and neuroimaging research.     

Limb immobilization for the treatment of focal occupational dystonia

BACKGROUND: Occupational focal upper-limb dystonia is characterized by involuntary muscle contractions that selectively interfere with the execution of specific motor tasks such as writing or playing a musical instrument. Occupational dystonias have a severe social impact, especially in certain professions. The available medical treatments offer little benefit. METHODS: In eight patients with idiopathic occupational focal dystonia of the upper limb, the dystonic forearm and hand were immobilized with a plastic splint for mean (+/-SD) 4.5 +/- 0.75 weeks. Before splinting (base line) and at various intervals afterwards (4, 12, and 24 weeks), the authors assessed the severity of dystonia and the patients' motor performance objectively (Arm Dystonia Disability Scale and Tubiana and Chamagne Score) and subjectively (Self-Rating Score). RESULTS: Assessment 4 weeks after splint removal, when patients had regained normal voluntary movements, showed that the severity of dystonia and the patients' performance of the impaired motor task had improved; the benefit persisted unchanged at later follow-up visits (Arm Dystonia Disability Scale: base line 20.6 +/- 30.2%; after 4 weeks 83.9 +/- 23.8%, p = 0.007; after 12 weeks 83.9 +/- 23.8%, p = 0.007; after 24 weeks 79.7 +/- 29.5%, p = 0.015. Tubiana and Chamagne Score: base line 28.6 +/- 22.7%; after 4 weeks 80.0 +/- 23.1%, p = 0.015; after 12 weeks 80.0 +/- 23.1%, p = 0.015; after 24 weeks 74.3 +/- 32.1%, p = 0.031. Self-Rating Score: base line 20.6 +/- 19.3%; after 4 weeks 63.7 +/- 25.2%, p = 0.015; after 12 weeks 66.9 +/- 28.1%, p = 0.015; after 24 weeks 70.6 +/- 31.8%, p = 0.015). At the 24-week visit the improvement disappeared in one patient, was moderate in three, and marked in four. CONCLUSIONS: Limb immobilization can be a simple, effective, safe, and inexpensive treatment for focal occupational upper-limb dystonia.     

Subjective perception of sleep benefit in Parkinson's disease: Valid or irrelevant?

IntroductionThe phenomenon of sleep benefit (SB) in Parkinson's disease (PD), whereby waking motor function is improved despite no dopaminergic treatment overnight, is controversial. Previous studies suggested a significant discrepancy between subjective functional and objective motor improvement. The aim of this study was to determine how well subjective reporting of SB correlates with objective measures and if true motor improvement can be predicted by a standardized questionnaire.MethodsNinety-two patients with PD participated. A structured questionnaire was developed to assess subjective SB. Quantitative motor assessment was performed using a validated smartphone application. Objective motor SB was considered to be present when the waking motor function was similar or superior to the daytime on-state.ResultsTwenty (22%) patients showed objective motor improvement on waking compared to end-of-dose. Most patients (77%) reported subjective SB without corresponding objective motor benefit. Our structured questionnaire could not predict Motor SB. The ability to delay morning medications and a perception of indifference or paradoxical worsening following the morning levodopa dose may suggest Motor SB.ConclusionsMost patients experience subjective SB with no measureable motor improvement. This perceived benefit could be related to non-motor improvement that is distinctly different to objective motor benefit.     

Motor and non-motor features of Parkinson's disease that predict persistent drug-induced Parkinsonism

BackgroundDrug-induced Parkinsonism is common, causes significant morbidity, and can be clinically indistinguishable from idiopathic Parkinson's disease. Additionally, drug-induced Parkinsonism may, in some cases, represent “unmasking” of incipient Parkinson's disease. Clinical features or tests that distinguish degenerative from pharmacologic Parkinsonism are needed.MethodsWe performed a retrospective case-control study of 97 drug-induced Parkinsonism subjects and 97 age-matched patients with Parkinson's disease. We compared the frequency of subjective motor and non-motor complaints, objective motor findings (Unified Parkinson's Disease Rating Scale Part III) and, where available, objective olfactory tests. We also performed a nested case-control study wherein we compared these same features between drug-induced Parkinsonism patients based on whether or not they recovered after changing the offending agent.ResultsNon-motor symptoms including constipation and sexual dysfunction were more common in Parkinson's disease than in drug-induced Parkinsonism. While total motor scores were similar between groups, Postural Instability-Gait Difficulty scores were also higher in Parkinson's disease. Features that were significantly different or showed a trend towards significance in both comparisons included subjective loss of facial expression, dream-enactment behavior, autonomic complaints and Postural Instability-Gait Difficulty scores. Hyposmia was more common in Parkinson's disease and was strongly predictive of persistent drug-induced Parkinsonism after therapy change (odds ratio 30.3, 95% confidence interval: 1.5–500, p = 0.03).ConclusionsA constellation of motor and non-motor features may differentiate unmasked Parkinson's disease from drug-induced Parkinsonism. In particular, olfactory testing may offer a simple and inexpensive method to help predict outcomes in drug-induced Parkinsonism and, potentially, identify a cohort of pre-motor Parkinson's disease.     

Botulinum toxin injections in the treatment of musician's dystonia

The authors present the results of 84 musicians with focal task-specific dystonia treated with EMG-guided botulinum toxin injections. Treatment outcome was assessed by subjective estimation of playing before and after treatment and self-rating of treatment response. Fifty-eight (69%) of the musicians experienced improvement from the injections and 30 of 84 musicians (36%) reported long-term benefit in their performance ability.     

The changes of exercise pattern and clinical symptoms in patients with Parkinson's disease in the era of COVID-19 pandemic

IntroductionThe coronavirus disease 2019 (COVID-19) pandemic has disrupted everyday life of Parkinson's disease (PD) patients, but its clinical impact has not been illustrated. In this study, we investigated the change in physical activity and subsequently clinical symptoms of PD during the COVID-19 pandemic.MethodsWe enrolled PD patients who were able to ambulate independently and had visited our clinic at Samsung Medical Centre from December 2019 to January 2020 (baseline) and in May 2020 (follow-up during the COVID-19 crisis), and divided them into either ‘the sustained exercise group’ or ‘the reduced exercise group’. Then, we assessed the change in the exercise and clinical features between these two groups over the study period.ResultsA total of 100 subjects were recruited. During the COVID-19 pandemic, the amount, duration and frequency of exercise were reduced. There was decrease in number of patients who do indoor-solo exercise and increase in that of patients who do not exercise. One third reported subjective worsening of both motor and non-motor features, although Unified PD Rating Scale (UPDRS) part 3 score was similar. Additionally, the reduced exercise group reported more motor and non-motor aggravation than the sustained exercise group, despite lack of significant difference in the UPDRS part 3 score.ConclusionThe COVID-19 pandemic had a clear impact on exercise and subjective symptoms in PD patients, with reduced exercise being related to a subjective increase in both motor and non-motor symptoms of PD. Maintaining exercise should therefore be emphasized even in situations like the COVID-19 pandemic.     

Learning effects of piano playing on tactile recognition of sequential stimuli

To examine the effect of learning experiences of piano playing on a tactile sequential recognition task, two experiments were conducted. In the first experiment, pianists and control subjects were given sequential tactile stimuli and were asked to report the simulated fingers and the order. The pianists showed a left hand superiority and performed better than the control group. In the second experiment, the skilled pianists and the control subjects were given both sequential tactile stimuli and auditory stimuli (unrelated melodies) simultaneously. The sequential stimuli recognition of the skilled pianists was interfered with by the presentation of the unrelated melody, and this tendency was more prominent in their left hand, while the performance of the control subjects was not affected by the presentation of the melody. These results suggest that pianists employed a special strategy, such as transforming tactile stimuli into something like a melody to improve their performance. Based upon these results, effects of learning experiences on hemisphere function were discussed.