Background: The vestibular evoked myogenic potential (VEMP) is a technique used to assess vestibular function. Cervical VEMPs (cVEMPs) are obtained conventionally from the sternocleidomastoid (SCM) muscle; however, the dorsal neck muscle splenius capitis (SPL) has also been shown to be a reliable target alongside the SCM in young subjects.
Objective: This study aimed to compare cVEMPs from the SCM and SPL in two positions across young, older, and Parkinson's disease (PD) patients.
Method: Experiments were carried out using surface EMG electrodes placed over the SCM and SPL. cVEMPs were measured using a 30 s, 126 dB sound stimulus with 222 individual tone bursts, while subjects were in a supine and head-turned posture (also known as the head elevation method), and in a seated head-turned posture.
Results: When comparing cVEMPs across positions, the incidence of supine and seated SCM-cVEMPs diminished significantly in older and PD patients in comparison with young subjects. However, no statistically significant differences in incidences were found in seated SPL-cVEMPs when comparing young, older and PD patients. SPL-cVEMPs were present significantly more often than seated SCM-cVEMPs in PD patients.
Conclusions: SPL-cVEMPs are not altered to the same extent that SCM-cVEMPs are by aging and disease and its addition to cVEMP testing may reduce false-positive tests for vestibulopathy.
Keywords: Cervical vestibular evoked myogenic potential; Splenius capitis; Sternocleidomastoid.