Frequency Following Responses in childhood apraxia of speech.

OBJECTIVE: to compare the Frequency Following Responses of children with childhood apraxia of speech with typical development children. METHOD: this is an observational cross-sectional analytical study approved by Human Research Ethics Committee. Thirty normal hearing children have participated in the study. THEY WERE DIVIDED INTO TWO GROUPS: 1) study group - composed by 15 children diagnosed with childhood apraxia of speech (between the chronological ages of 3 and 11 years, mean age of 5,7 years); and 2) control group: composed by 15 children with typical development, paired by age and gender with study group. Frequency Following Response were recorded using the/da/syllable presentation rate at 10.9 ms. RESULTS: there was a significant delay in latencies of waves V, A and C of children with apraxia of speech, suggesting difficulties in the ability to process sounds. CONCLUSION: The delay on Frequency Following Response's latencies (waves V, A and C) in children with apraxia of speech maybe related to atypical neural coding of speech sounds, suggesting that apraxia of speech must not be purely considered as a motor speech disorder.

Amplitude modulated vestibular evoked myogenic responses: a study of carrier and modulating frequencies.

CONCLUSION: Responses with greater amplitude were recorded when carrier frequencies were modulated at 37, 40, and 43 Hz. These responses can be recorded even in patients with significant sensorineural hearing loss, from the sternocleidomastoid (SCM) muscle for a 500 Hz tone, 100% modulated at 40 Hz. OBJECTIVE: To determine the best carrier and modulating frequencies to evoke steady-state myogenic responses. METHODS: The present study investigated 156 ears of 78 normal-hearing young adults, with carrier frequencies of 250, 500, and 1000 Hz, modulated at 20, 37, 40, 43, 70, 77, and 80 Hz, with an intensity of 95 dBA. Furthermore, we observed responses evoked by stimulus carrier frequency of 500 Hz, modulated at 40 Hz, with an intensity of 95 dBA in a group of five subjects with severe sensorineural loss. RESULTS: Responses were found for all stimuli studied (p < 0.01). Modulated stimuli at frequencies of 37, 40, and 43 Hz evoked better steady-state vestibular evoked myogenic potential (S-VEMP) (p < 0.05). No statistically significant differences were found between the group of normal hearers and the group of subjects with hearing loss (p = 0.431), for the stimulus used.

Saccular sensitivity function measured by vestibular evoked myogenic potential.

CONCLUSIONS: Vestibular myogenic potential responses were present when evoked by tone burst stimuli of 250, 500, 1000, and 2000 Hz; however, they were more effective for low-frequency stimuli. OBJECTIVES: Few studies refer to specific frequency sensitivities of the saccular afferents. Accordingly, the aim of the present study was to analyze p13 and n23 latency and amplitude parameters of vestibular evoked myogenic potential (VEMP) captured with tone bursts at frequencies of 250, 500, 1000, and 2000 Hz. METHODS: VEMP was captured in 156 ears (78 subjects), recorded in the sternocleidomastoid muscle, averaging 200 stimuli, stimulus rate of 5 Hz, duration 10 ms (rise, 4 ms; plateau, 2 ms; fall, 4 ms), at intensity of 95 dB nHL. The recordings were performed in 50 ms windows. RESULTS: We found lower p13 latencies in women compared with men, except for the frequency of 250 Hz. We found higher mean absolute latency values for p13 and n13 and lower p13-n13 amplitude and p13-n13 inter-peak values for a frequency of 2000 Hz. Higher amplitudes were observed at frequencies of 250 and 500 Hz. When frequencies of 250, 500, 1000, and 2000 Hz were compared using ANOVA, we found statistically significant differences for all the VEMP parameters (p ≤ 0.005).