Pre-movement gating of somatosensory evoked potentials in Tourette syndrome

Kazue Kimura; Nagako Murase; Yuri Nagao; Maki Nozaki; Michio Fukumizu; Yosuke Kita; Masaharu Hayashi; Kyoko Hoshino

doi:10.1016/j.braindev.2023.02.002

Pre-movement gating of somatosensory evoked potentials in Tourette syndrome

Brain Dev. 2023 Jun;45(6):324-331. doi: 10.1016/j.braindev.2023.02.002. Epub 2023 Mar 4.

Authors

Kazue Kimura¹, Nagako Murase², Yuri Nagao³, Maki Nozaki³, Michio Fukumizu³, Yosuke Kita⁴, Masaharu Hayashi³, Kyoko Hoshino³

Affiliations

¹ Segawa Memorial Neurological Clinic for Children, Tokyo, Japan. Electronic address: kimura@segawa-clinic.jp.
² Department of Neurology, National Hospital Organization, Nara Medical Center, Nara, Japan.
³ Segawa Memorial Neurological Clinic for Children, Tokyo, Japan.
⁴ Department of Psychology, Faculty of Letters, Keio University, Tokyo, Japan; Cognitive Brain Research Unit (CBRU), Faculty of Medicine, University of Helsinki, Helsinki, Finland.

PMID: 36878743
DOI: 10.1016/j.braindev.2023.02.002

Abstract

Objective: Tourette syndrome (TS) is a neurobehavioral disorder characterized by motor and vocal tics. Simple tics are purposeless involuntary movements that spontaneously resolve during middle adolescence. Complex tics appear to be semi-voluntary movements that may become intractable when associated with obsessive-compulsive disorder (OCD). Sensory tics or urges preceded by tics suggest sensorimotor processing impairment in TS. We aimed to clarify its pathophysiology by exploring the pre-movement gating (attenuation) of somatosensory evoked potentials (SEPs).

Methods: We examined 42 patients (aged 9-48 years), 4 of whom underwent follow-up assessment, along with 19 healthy controls. We defined patients with only simple tics as TS-S and patients with complex tics as TS-C. Pre-movement gating of SEPs was assessed using a previously described method. Frontal N30 (FrN30) amplitudes were compared between pre-movement and resting states. The gating ratio of pre-movement/resting amplitude of the FrN30 component was assessed: the larger the ratio, the less the gating.

Results: The gating ratio for TS-C patients was larger than that of TS-S patients and healthy controls, but a statistical difference between TS-S and TS-C appeared after 15 years and over (p < 0.001). There were no significant differences in the gating ratio between TS-S patients and healthy controls. The gating ratio was related to the severity of OCD (p < 0.05).

Conclusion: Sensorimotor processing was preserved for simple tics but impaired in complex tics, specifically after middle adolescence. Our study supports an age-dependent dysfunction of both motor and non-motor cortico-striato-thalamo-cortical circuits in complex tics. SEP gating seems promising as a tool for assessing age-dependent sensorimotor disintegration in TS.

Keywords: Complex tic; Gating of somatosensory evoked potentials (SEPs); Obsessive compulsive disorder; Sensorimotor integration; Simple tic; Tourette syndrome.

MeSH terms

Adolescent
Evoked Potentials, Somatosensory / physiology
Humans
Movement / physiology
Tic Disorders*
Tics*
Tourette Syndrome* / complications