Electroclinical Features of Sleep-Related Head Jerk

STUDY OBJECTIVES: To evaluate clinical and electrophysiological features of sleep-related head jerk (SRHJ) and electromyographic activity of superficial neck muscles during head jerk. METHODS: Totally, 850 cases with video-polysomnography recording were collected, among which 50 presented with SRHJ. In these 50 patients, 15 underwent electromyography (EMG) check on bilateral sternocleidomastoid (SCM) and trapezius muscles as well as chin, while 35 had only chin EMG check. Further, the sensitivity and specificity of the both EMGs were calculated and compared. RESULTS: Six among the 50 SRHJ patients had a primary complaint of involuntary head jerks associated with impaired sleep. Approximately 76.1% of head jerks occurred during REM sleep with the median head jerk index of 5.9/h, 64.5% of which were associated with electroencephalogram arousals and 66.4% with body movements. One patient showed SRHJ predominantly in NREM sleep but also in wakefulness. Surface EMG of SCM/trapezius muscles showed a sensitivity of 92% and a specificity of 97.8%, whereas chin EMG had a sensitivity of 14.5% and a specificity of 98.8%. CONCLUSION: SRHJ was associated with electroencephalogram arousals and might interfere with sleep. Surface EMG of SCM/trapezius muscles exhibited a good accuracy in the revelation of SRHJ.