Multidomain Polysomnographic Abnormalities in Cervical Dystonia: REM Suppression, Respiratory Instability, and Sensorimotor Dysregulation

BACKGROUND: Cervical dystonia (CD) is considered a basal ganglia-thalamo-cortical and brainstem network disorder rather than an isolated focal motor disease. OBJECTIVES: Our aim was to analyze sleep architecture, REM physiology, respiratory patterns, and sensorimotor activity in CD using full-night PSG. METHODS: We conducted a full-night PSG case-control analysis involving 33 CD patients and 20 matched controls. Clinical scales used were Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS), Craniocervical Dystonia Questionnaire (CDQ-24), Beck Depression Inventory (BDI), Beck Anxiety Inventory (BAI), and Brief Psychiatric Rating Scale (BPRS). RESULTS: CD patients showed greater sleep disruption than controls with significantly decreased total sleep time (TST) and reduced sleep efficiency (SE). Wake after sleep onset (WASO) was considerably higher. >70% met criteria for a study-defined severe insomnia pattern (<25% of controls). REM was absent in 42% of patients and overall REM percentage was reduced by ~70%. CD showed nearly three-fold higher apnea-hypopnea index (AHI), a significantly higher obstructive apnea index, and prolonged respiratory event duration. Periodic limb movements (PLMS) index was ~14 times higher. Spontaneous arousal rates were significantly increased. Greater motor disability (TWSTRS) correlated with decreased N3 sleep. Higher Tsui severity correlated with increased N2 sleep, linking clinical severity to altered sleep architecture. BDI correlated with higher AHI, greater respiratory event burden and obstructive apnea index. PLMS index showed strong internal coupling with PLMS arousal index and correlated with cardiac parameters. CONCLUSION: Sleep measures may offer a useful non-invasive perspective on distributed network features associated with CD. These findings are associative and require replication in larger cohorts.