Normal Temporal Discrimination in Musician's Dystonia Is Linked to Aberrant Sensorimotor Processing

Abstract

A BS TRACT: Objectives: Alterations in sensory discrimination are a prominent nonmotor feature of dystonia. Abnormal temporal discrimination in focal dystonia is considered to represent its mediational endophenotype, albeit unclear pathophysiological correlates. We examined the associations between the visual temporal discrimination threshold (TDT) and brain activity in patients with musician's dystonia, nonmusician's dystonia, and healthy controls. Methods: A total of 42 patients and 41 healthy controls participated in the study. Between-group differences in TDT z scores were computed using inferential statistics. Statistical associations of TDT z scores with clinical characteristics of dystonia and resting-state functional brain activity were examined using nonparametric rank correlations. Results: The TDT z scores of healthy controls were significantly different from those of patients with nonmusician's dystonia, but not of patients with musician's dystonia. Healthy controls showed a significant relationship between normal TDT levels and activity in the inferior parietal cortex. This relationship was lost in all patients. Instead, TDT z scores in musician's dystonia established additional correlations with activity in premotor, primary somatosensory, ventral extrastriate cortices, inferior occipital gyrus, precuneus, and cerebellum, whereas nonmusician's dystonia showed a trending correlation in the lingual gyrus extending to the cerebellar vermis. There were no significant relationships between TDT z scores and dystonia onset, duration, or severity. Conclusions: TDT assessment as an endophenotypic marker may only be relevant to nonmusician forms of dystonia because of the lack of apparent alterations in musician's dystonia. Compensatory adaptation of neural circuitry responsible for TDT processing likely adjusted the TDT performance to the behaviorally normal levels in patients with musician's dystonia, but not nonmusician's dystonia.

Short- and Long-term Central Action of Botulinum Neurotoxin Treatment in Laryngeal Dystonia

“…The role of precuneus in the pathophysiology of dystonia remains elusive as this region has been, by and large, out of focus of studies investigating major basal ganglia-thalamosensorimotor and cerebellar impairments in this disorder. However, several recent investigations have noted abnormal precuneus function and structure in LD and other focal dystonias, such as blepharospasm, Meige syndrome, cervical and musician's dystonias [26][27][28][29][30][31] . Evidence from these studies suggests that precuneus alterations may play a role in subtle deficits of cognitive function in dystonia patients, including impaired visuospatial attention 32,33 , temporal discrimination 29,34 , motor imagery or spatially guided behaviors 35 .…”

“…However, several recent investigations have noted abnormal precuneus function and structure in LD and other focal dystonias, such as blepharospasm, Meige syndrome, cervical and musician's dystonias [26][27][28][29][30][31] . Evidence from these studies suggests that precuneus alterations may play a role in subtle deficits of cognitive function in dystonia patients, including impaired visuospatial attention 32,33 , temporal discrimination 29,34 , motor imagery or spatially guided behaviors 35 . It is plausible that restoration of precuneus activity with BoNT treatment, as shown in the current study, might have an impact on improved cognitive function in these patients.…”

Neurophysiological insights in dystonia and its response to deep brain stimulation treatment

“…Abnormally prolonged sensory temporal discrimination thresholds in dystonia can be further worsened by high-frequency peripheral sensory stimulation, suggesting abnormal plasticity with the primary somatosensory cortex (Erro et al 2018 ). Perhaps surprisingly, in idiopathic isolated generalized dystonia tactile spatial sensory discrimination is normal (Molloy et al 2003 ) and visual temporal discrimination thresholds are normal in patients with musician’s dystonia (Maguire et al 2020 ) perhaps reflecting better recompensation among elite musicians. Abnormally prolonged sensory temporal discrimination thresholds are present in functional dystonia to the same degree as organic dystonia (Morgante et al 2011 ) interpreted as evidence for possible endophenotypic overlap between these disorders.…”

Impaired feedforward control of movements in pianists with focal dystonia

“…Although the causes of FHD are still being investigated, a possible triggering factor is the repetitive training of precise motions (5). Individuals with FHD demonstrate various symptoms, such as loss of fine motor control (26), atypical joint coordination (27), and impaired non-motor functions (28).…”