Drumming performance and underlying muscle activities in a professional rock drummer with lower-limb dystonia: a case study.

Task-specific focal dystonia (TSFD), characterized by the loss of fine motor control and coordination, affects drummers' lower-limb movements. This study explores lower-limb dystonia's impact on drumming performance and underlying muscle activity in a professional rock drummer. The drummer executed an eight-beat pattern on a drum kit. The participant reported the occurrence of symptoms when he felt the abnormality such as the loss of control related to involuntary aspects of movement. We measured the peak amplitude of the bass drumhead vibration, synchronization errors as the time elapsed between the metronome onset and the bass drum onset, and amplitude of electromyographic (EMG) recordings centered on metronome beat. Dystonia symptoms primarily manifested in the initial beat, with fewer symptoms on syncopation of the third beat. Analysis revealed decreased bass-drum peak amplitude and earlier synchronization error during the initial beat. EMG measurements of 10 muscles in the affected right lower limb showed significant changes in the Biceps Femoris (BF), Tibialis Anterior (TA), Extensor Digitorum Longus (EDL), and Extensor Digitorum Brevis (EDB) muscles during symptom onset. We observed (1) earlier overactivation of the TA and EDL muscles during the leg lift-up motion or preparatory phase of pedaling, (2) reduced activation of the EDB muscle, and (3) increased activation of the BF muscle during the final pedaling movement when symptoms occurred. These findings suggest that lower-limb dystonia symptoms are characterized by a reduction in amplitude of the bass drumhead vibration and an increase in synchronization error, potentially due to premature overactivation of the ankle dorsiflexor muscles.

Probing the inhibitory motor circuits in adductor laryngeal dystonia during a dystonia-unrelated task.

BACKGROUND: The pathophysiology of adductor laryngeal dystonia (AdLD) remains unknown; however, there is growing evidence that dystonia is associated with disruptions in the inhibitory regulation of sensorimotor cortical areas. Using functional MRI (fMRI) and transcranial magnetic stimulation (TMS) complementarily, we previously demonstrated an overly activated laryngeal motor cortex and revealed correlations between blood-oxygen-level dependent (BOLD) activation and intracortical inhibition in a phonation (dystonia-related) task in adductor laryngeal dystonia (AdLD). OBJECTIVE: Here, we aimed to characterize the brain-based findings in the primary motor cortex (M1) during a dystonia-unrelated (finger tapping) task in AdLD and controls (CTL). METHODS: We examined the between-group differences in task-dependent BOLD activation and intracortical inhibition, measured by the TMS-evoked cortical silent period (cSP), in the M1. The correlations between fMRI and TMS responses were assessed. RESULTS: There is more broadly dispersed BOLD activation, not confined to the hand motor cortex, and reduced intracortical inhibition in AdLD compared to CTL. Further, there are more positive correlations between cSP and BOLD activation in a task unrelated to dystonic symptoms in AdLD compared with CTL. This is in contrast to our previous work that demonstrated fewer positive correlations in AdLD during a dystonic phonation task. CONCLUSIONS: In unaffected musculature activation, there is dispersed BOLD activation that is correlated with intracortical inhibition suggesting a possible compensatory strategy in the non-dystonic muscles.

[Abnormal movements "Motare" in Kyudo have the characteristics of task-specific focal dystonia].

Among the abnormal kyudo movements ("yips"), "motare" is the inability to release the arrow at the intended timing if aiming the target. We hypothesized that "motare" is a task-specific focal dystonia (TSFD). We interviewed three participants with "motare," three participants with "hayake", and three controls without "motare" nor "hayake". Moreover, we conducted a surface electromyography (sEMG) examination and found that "motare" was characterized by stereotypy, sensory tricks, and morning benefit; however, these findings were not observed in "hayake". Abnormal co-contraction of the upper extremity antagonist muscles was observed in one of the three "motare" participants. Overall, these findings suggest that "motare" have the characteristics of TSFD not previously reported.

[Yips in Kyudo (Japanese archery): prevalence, classification, and aggravating factors].

In Kyudo (Japanese archery), there are four disorders that hinder an archer's performance: Hayake (releasing the bow too early), Motare (unable to release the bow when intended), Biku (jerking when aiming), and Yusuri (shaking when drawing the bow, or aiming). These disorders are similar to Yips, a psycho-neuromuscular movement disorder, recognized in various sports, but few studies have examined yips in Kyudo. This study examined the frequency, classification, and risk factors of yips in Kyudo among medical students. The results showed that 41 of 65 students (63.1%) experienced at least one disorder. The frequency of Hayake was the highest (35 patients; 85.3%). An experience of playing was associated with the increased risk of yips in Kyudo. Motare was the only disorder that appeared on its own, and without complications from other disorders. Based on its characteristics, it was suspected that task-specific focal dystonia involved in Motare.

Symptom Locus and Symptom Origin Incongruity in Runner's Dystonia - Case Study of an Elite Female Runner.

Objectives: Runner's dystonia is a task-specific dystonia that occurs in the lower limbs and trunk, with diverse symptomatology. We aimed to identify the origin of a dystonic movement abnormality using combined three-dimensional kinematic analysis and electromyographic (EMG) assessment during treadmill running. Participant: A 20-year-old female runner who complained of right-foot collision with the left-leg during right-leg swing-phase, which mimicked right-ankle focal dystonia. Results: Kinematic and EMG assessment of her running motion was performed, which showed a significant drop of the left pelvis during right-leg stance-phase, and a simultaneous increase of right hip adductor muscle activity. This resulted in a pronounced adduction of the entire right lower limb with respect to the pelvis segment. Trajectories of right foot were seen to encroach upon left-leg area. Discussion: These findings suggested that the symptom of this runner was most likely a form of segmental dystonia originating from an impaired control of hip and pelvis, rather than a distal focal ankle dystonia. Conclusion: We conclude that, for individualized symptom assessment, deconstructing the symptom origin from its secondary compensatory movement is crucial for characterizing dystonia. Kinematic and EMG evaluation will therefore be a prerequisite to distinguish symptom origin from secondary compensatory movement.

Task-specificity in focal dystonia is shaped by aberrant diversity of a functional network kernel.

OBJECTIVES: Task-specific focal dystonia selectively affects the motor control during skilled and highly learned behaviors. Recent data suggest the role of neural network abnormalities in the development of the pathophysiological dystonic cascade. METHODS: We used resting-state functional MRI and analytic techniques rooted in network science and graph theory to examine the formation of abnormal subnetwork of highly influential brain regions, the functional network kernel, and its influence on aberrant dystonic connectivity specific to affected body region and skilled motor behavior. RESULTS: We found abnormal embedding of sensorimotor cortex and prefrontal thalamus in dystonic network kernel as a hallmark of task-specific focal dystonia. Dependent on the affected body region, aberrant functional specialization of the network kernel included regions of motor control management in focal hand dystonia (writer's cramp, musician's focal hand dystonia) and sensorimotor processing in laryngeal dystonia (spasmodic dysphonia, singer's laryngeal dystonia). Dependent on skilled motor behavior, the network kernel featured altered connectivity between sensory and motor execution circuits in musician's dystonia (musician's focal hand dystonia, singer's laryngeal dystonia) and abnormal integration of sensory feedback into motor planning and executive circuits in non-musician's dystonia (writer's cramp, spasmodic dysphonia). CONCLUSIONS: Our study identified specific traits in disorganization of large-scale neural connectivity that underlie the common pathophysiology of task-specific focal dystonia while reflecting distinct symptomatology of its different forms. Identification of specialized regions of information transfer that influence dystonic network activity is an important step for future delineation of targets for neuromodulation as a potential therapeutic option of task-specific focal dystonia. © 2018 International Parkinson and Movement Disorder Society.

Activity and topographic changes in the somatosensory system in embouchure dystonia.

BACKGROUND: Embouchure dystonia is a highly disabling focal task-specific dystonia affecting professional brass players. OBJECTIVE: This study was designed to analyze activity changes along with topographic representations in primary and nonprimary centers for somatosensory processing in patients with embouchure dystonia. METHODS: We used event-related functional magnetic resonance imaging with automized tactile stimulation of dystonic (upper lip) and nondystonic (forehead and dorsal hand) body regions in 15 professional brass players with and without embouchure dystonia. Statistical analyses included whole-brain between-group comparisons of stimulation-induced activation and region-of-interest-based single patient analyses of topographic activation characteristics. RESULTS: Affected musicians revealed increased stimulation-induced activity in contralateral primary and bilateral secondary somatosensory representations of dystonic and nondystonic body regions as well as in the cerebellum ipsilateral to the left dystonic upper lip. Changes of somatotopic organization with altered intracortical distances and between-group differences of the centers of representations were found in the right primary and the bilateral secondary somatosensory cortex and in the left cerebellum. Positional variability of dystonic and nondystonic body regions was reduced with an emphasis on face representations. CONCLUSIONS: The present findings are supportive of the concept of an abnormal processing of somatosensory information in embouchure dystonia affecting multiple domains. The underlying neurophysiological mechanisms (eg, changes in inhibition, maladaptive plasticity, changes in baseline activity) remain unclear. The involvement of nondystonic body areas can be viewed in the context of possible compensation or an endophenotypic predisposition. © 2016 International Parkinson and Movement Disorder Society.