Clinical and electrophysiological value of sensory tricks in cervical dystonia

Abstract

Objective To investigate demography of sensory tricks in cervical dystonia (CD), and to discuss the relationship between sensory tricks and the function of sensorimotor integration of cerebral cortex, meanwhile to explore potential worthiness using sensory tricks in the management of CD. Methods We recruited 75 patients (23 male, 52 female, male female ratio: 1∶2.26; aged 19-72 years, mean (42.45±13.09) years) admitted to the Dystonia Clinic Center of the First Affiliated Hospital of Dalian Medical University from March 2016 to April 2013. Standardized questionnaire on sensory tricks was used to investigate the sensory tricks first recognized in 75 patients retrospectively. Median nerve somatosensory evoked potential via multipoint recording was measured in 43 CD patients who manifested as simple rotation of neck. Bilateral amplitudes of P22/N30 derived from F(3, 4)were compared. Results Frequency of sensory tricks in CD was 85.53% (64/75) in our research. As disease progressed, the type of sensory tricks used by patients may transform from one to another or even disappear. No statistically significant differences were found in ages among patients using classic sensory tricks, forcible tricks and patients without sensory tricks, whereas the complexity of the disease showed increased tendency among the three groups. Bilateral P22/N30 amplitudes of patients with classic sensory tricks showed no significant differences. P22/N30 amplitudes contralateral to the head turn were significantly higher than ipsilateral in patients using forcible tricks ((3.16±1.71) μV vs (2.47±1.28) μV, t=2.243, P=0.038) and patients without sensory tricks ((3.62±1.58) μV vs (2.73±1.14) μV, t=2.893, P=0.023). Tsui scores among patients using classic sensory tricks (9.36±3.52)and forcible tricks (12.67±5.00)or patients without sensory tricks (15.18±4.07)had statistically significant differences (classic sensory tricks vs forcible tricks, t=-3.020, P=0.004; classic sensory tricks vs patients without sensory tricks, t=-4.452, P=0.000). Conclusions Types of sensory tricks used by patients are associated with severity of the disease. Different types of sensory tricks may reflect status of adaptive compensatory mechanism of the cerebral cortex. Key words: Torticollis; Sensory tricks; Supplementary motor area; Evoked potentials, somatosensory