Chirp-Evoked VEMPs: A Test-Retest Reliability Study.

OBJECTIVES: To determine the test-retest reliability of cervical and ocular vestibular-evoked myogenic potentials (c&oVEMP) evoked by 500 Hz narrowband (NB) CE-Chirp and broadband (BB) CE-Chirp stimuli. DESIGN: Twenty healthy participants (10 female) were tested twice on the same day to determine the within-session reliability and 1 week later to determine the between-session reliability. The latency, amplitude, and asymmetry ratio of c&oVEMPs elicited by 95 dB nHL air-conducted (AC) 500 Hz NB CE-Chirp and BB CE-Chirp were recorded bilaterally. RESULTS: A moderate to good between-session reliability with intraclass correlation coefficient (ICC) values ranging from 0.52 to 0.82 was observed for cVEMP latency, amplitude, and asymmetry ratio evoked by 500 Hz NB CE-Chirp, as well as for the BB CE-Chirp cVEMP amplitude (ICC of 0.70 and 0.84). In contrast, an overall poor reliability ICC values between 0.30 and 0.42 for cVEMP latency and asymmetry ratio were observed for BB CE-Chirp. For the oVEMP, overall poor between-session reliability for all response parameters evoked by the 500 Hz NB CE-Chirp and the BB CE-Chirp was observed. CONCLUSIONS: The 500 Hz NB CE-Chirp was more reliable than the BB CE-Chirp in terms of cVEMP latency, amplitude, and asymmetry ratio. Further investigation using the standard electrode montage is necessary to assess the test-retest reliability of the chirp-evoked oVEMP.

Cervical and ocular vestibular evoked myogenic potential: A comparison of narrowband chirp, broadband chirp, tone burst and click stimulation.

OBJECTIVES: To compare the response rate and response parameters of cervical and ocular vestibular evoked myogenic potentials (c&oVEMP) elicited by narrowband (NB) and broadband (BB) CE-Chirp, with the more classical tone burst (TB) and click VEMPs. DESIGN: The response rate, latency, amplitude and asymmetry ratio of c&oVEMPs elicited by 95 dB nHL air conducted (AC) 500 Hz NB CE-chirp, BB CE-chirp, 500 Hz TB and click stimuli were recorded bilaterally. STUDY SAMPLE: 20 male and 38 female participants (19-39 years). RESULTS: For the cVEMP, the highest response rate was found for NB chirp (100%), followed by TB (91%), BB chirp (87%) and finally click (85%). A similar order was seen for oVEMP with percentages of 100%; 57%, 57%, and 43%. The 500 Hz NB CE-Chirp elicited significantly shorter cVEMP P1 and N1 latencies and significantly larger c&oVEMP amplitudes compared to all other stimuli. BB CE-Chirp elicited significantly shorter c&oVEMP P1 and N1 latencies with smaller amplitudes compared to TB. Asymmetry ratios were not statistically significant for all comparisons. CONCLUSION: The 500 Hz NB CE-chirp provides the highest response rates, shorter latencies and larger amplitudes, and therefore seem a promising stimulus for reliably measuring c&oVEMPs in clinical practice.