Simultaneous Recordings of Cervical and Ocular Vestibular-Evoked Myogenic Potentials

BACKGROUND: Cervical (cVEMP) and ocular (oVEMP) vestibular-evoked myogenic potentials are short-latency manifestations of vestibulo-ocular and vestibulocollic reflexes that originate from the utricle and saccule. The aim of this study was to determine whether simultaneously recording cVEMP and oVEMP more reliably detects the reflex responses than when making separate recordings. METHODS: Both simultaneous recordings and conventional separate recordings of the cVEMP and oVEMP responses to air-conducted tone bursts were obtained in 39 healthy subjects. p13 and n10 latencies, and p13-n23 and n10-p16 amplitudes of cVEMP and oVEMP waveforms were measured, respectively. The asymmetry ratios (ARs) of the amplitudes were calculated. RESULTS: In cVEMP testing, the p13 latencies and p13-n23 amplitudes did not differ significantly between simultaneous and conventional separate recordings. In oVEMP testing, the n10 latencies measured in simultaneous recordings showed a small but statistically significant prolongation compared to the results in separate recordings. Moreover, the n10-p16 amplitudes were significantly larger in the simultaneous recordings. The AR of simultaneous recordings of cVEMP and oVEMP did not differ between the two recording methods. CONCLUSIONS: Simultaneously recording cVEMP and oVEMP provides a reliable test and could be a clinically useful and simplified diagnostic tool for evaluating dizzy patients.

Simultaneous Recordings of Cervical and Ocular Vestibular-Evoked Myogenic Potentials

BACKGROUND: Cervical (cVEMP) and ocular (oVEMP) vestibular-evoked myogenic potentials are short-latency manifestations of vestibulo-ocular and vestibulocollic reflexes that originate from the utricle and saccule. The aim of this study was to determine whether simultaneously recording cVEMP and oVEMP more reliably detects the reflex responses than when making separate recordings. METHODS: Both simultaneous recordings and conventional separate recordings of the cVEMP and oVEMP responses to air-conducted tone bursts were obtained in 39 healthy subjects. p13 and n10 latencies, and p13-n23 and n10-p16 amplitudes of cVEMP and oVEMP waveforms were measured, respectively. The asymmetry ratios (ARs) of the amplitudes were calculated. RESULTS: In cVEMP testing, the p13 latencies and p13-n23 amplitudes did not differ significantly between simultaneous and conventional separate recordings. In oVEMP testing, the n10 latencies measured in simultaneous recordings showed a small but statistically significant prolongation compared to the results in separate recordings. Moreover, the n10-p16 amplitudes were significantly larger in the simultaneous recordings. The AR of simultaneous recordings of cVEMP and oVEMP did not differ between the two recording methods. CONCLUSIONS: Simultaneously recording cVEMP and oVEMP provides a reliable test and could be a clinically useful and simplified diagnostic tool for evaluating dizzy patients.

Difference of Diagnostic Rates and Analytical Methods in the Test Positions of Vestibular Evoked Myogenic Potentials

OBJECTIVE: To compare the differences of diagnostic rates, of the two widely used test positions, in measuring vestibular evoked myogenic potentials (VEMP) and selecting the most appropriate analytical method for diagnostic criteria for the patients with vertigo. METHODS: Thirty-two patients with vertigo were tested in two comparative testing positions: turning the head to the opposite side of the evaluating side and bowing while in seated position, and bowing while in supine positions. Abnormalities were determined by prolonged latency of p13 or n23, shortening of the interpeak latency, and absence of VEMP formation. RESULTS: Using the three criteria above for determining abnormalities, both the seated and supine positions showed no significant differences in diagnostic rates, however, the concordance correlation of the two positions was low. When using only the prolonged latency of p13 or n23 in the two positions, diagnostic rates were not significantly different and their concordance correlation was high. On the other hand, using only the shortened interpeak latency in both positions showed no significant difference of diagnostic rates, and the degree of agreement between two positions was low. CONCLUSION: Bowing while in seated position with the head turned in the opposite direction to the area being evaluated is found to be the best VEMP test position due to the consistent level of sternocleidomastoid muscle tension and the high level of compliance. Also, among other diagnostic analysis methods, using prolonged latency of p13 or n23 as the criterion is found to be the most appropriate method of analysis for the VEMP test.

Difference of Diagnostic Rates and Analytical Methods in the Test Positions of Vestibular Evoked Myogenic Potentials

OBJECTIVE: To compare the differences of diagnostic rates, of the two widely used test positions, in measuring vestibular evoked myogenic potentials (VEMP) and selecting the most appropriate analytical method for diagnostic criteria for the patients with vertigo. METHODS: Thirty-two patients with vertigo were tested in two comparative testing positions: turning the head to the opposite side of the evaluating side and bowing while in seated position, and bowing while in supine positions. Abnormalities were determined by prolonged latency of p13 or n23, shortening of the interpeak latency, and absence of VEMP formation. RESULTS: Using the three criteria above for determining abnormalities, both the seated and supine positions showed no significant differences in diagnostic rates, however, the concordance correlation of the two positions was low. When using only the prolonged latency of p13 or n23 in the two positions, diagnostic rates were not significantly different and their concordance correlation was high. On the other hand, using only the shortened interpeak latency in both positions showed no significant difference of diagnostic rates, and the degree of agreement between two positions was low. CONCLUSION: Bowing while in seated position with the head turned in the opposite direction to the area being evaluated is found to be the best VEMP test position due to the consistent level of sternocleidomastoid muscle tension and the high level of compliance. Also, among other diagnostic analysis methods, using prolonged latency of p13 or n23 as the criterion is found to be the most appropriate method of analysis for the VEMP test.