Effects of Age and Middle Ear on the Frequency Tuning of the cVEMP and oVEMP

A meta-analysis comparing the performance of narrowband CE-Chirp and 500 Hz tone burst stimuli in recording cervical vestibular evoked myogenic potential (cVEMP)

Due to contradictory outcomes in the literature, the aim of this meta-analysis is to verify whether the narrowband (NB) CE-Chirp stimulus (centred at 500 Hz) would produce more robust cervical vestibular evoked myogenic potential (cVEMP) responses relative to the conventional 500 Hz tone burst. The literature search was conducted using PubMed, Scopus, and Web of Science databases and the terms used were "vestibular evoked myogenic potential" and "chirp". The cVEMP parameters to be analysed were P1 latency, N1 latency, and P1-N1 amplitude. A total of 59 potential articles were obtained from the database search. Eventually, five articles were found to be eligible for the meta-analysis (with n = 222). As found, P1 and N1 latencies of cVEMP were significantly shorter for the chirp stimulus (p < 0.001), with substantially large effect sizes. On the other hand, P1-N1 amplitude values were found to be not statistically different between the two stimuli (p = 0.189), with a small effect size. It appears that there is no indication to support the superiority of the NB CE-Chirp stimulus (centred at 500 Hz) in the cVEMP testing (relative to the conventional 500 Hz tone burst). In particular, both stimuli produce comparable P1-N1 amplitude values. Even though P1 and N1 latencies are statistically shorter for the chirp stimulus, this may not reflect that it should be the preferred stimulus for recording cVEMP responses (and the reasons for this are discussed accordingly).

Cervical vestibular evoked myogenic potential (cVEMP) findings in adults with sensorineural hearing loss (SNHL): comparisons between 500 Hz tone burst and narrowband CE-Chirp stimuli

There has been a growing interest in studying the usefulness of chirp stimuli in recording cervical vestibular evoked myogenic potential (cVEMP) waveforms. Nevertheless, the study outcomes are debatable and require verification. In view of this, the aim of the present study was to compare cVEMP results when elicited by 500 Hz tone burst and narrowband (NB) CE-Chirp stimuli in adults with sensorineural hearing loss (SNHL). Fifty adults with bilateral SNHL (aged 20-65 years) underwent the cVEMP testing based on the established protocol. The 500 Hz tone burst and NB CE-Chirp (centred at 500 Hz) stimuli were presented to each ear at an intensity level of 120.5 dB peSPL. P1 latency, N1 latency, and P1-N1 amplitude values were analysed accordingly. The NB CE-Chirp stimulus produced significantly shorter P1 and N1 latencies (p < 0.001) with large effect sizes (d > 0.80). In contrast, both stimuli elicited cVEMP responses with P1-N1 amplitude values that were not statistically different from one another (p = 0.157, d = 0.15). Additionally, age and hearing level were found to be significantly correlated (r = 0.56, p < 0.001), as were age and cVEMP amplitude for each stimulus (p < 0.001). To conclude, since both stimuli were presented at an equivalent intensity level (in dB peSPL), the shorter P1 and N1 latencies of cVEMP produced by the NB CE-Chirp stimulus (centred at 500 Hz) were unlikely due to enhanced saccular stimulation. Another more sensible reason is the temporal adjustment of the chirp stimulus.