- ENT Division, University of Turin, Italy
To assess differences in hearing threshold estimation of four different ABR tone-bursts at 1 kHz.
Twenty-one (21) ears from 11 subjects were tested with pure-tone audiometry (PTA):
5 ears (24%) were normal hearing,
5 (24%) affected by mild hearing loss,
7 (33%) showed moderate hearing loss and
4 (19%) severe hearing loss.
After PTA each subject underwent tone-burst ABR test at 1 kHz using
- a linear gated (L_ABR)
- or Blackman windowed (B_ABR) stimuli with (nn_ABR) and without ipsilateral notched noise.
Stimulation rate and filters settings were unchanged.
Overall correlation between PTA and all ABRs thresholds was high, ranging from 0.84 to 0.94.
In normal hearing ears none of the differences was significant, except for those measured with B_nn_ABR, which showed a mean 16 dB overestimation of the pure-tone threshold (p < 0.05).
In mild hearing loss group none of the differences between thresholds were significant.
In moderate and severe hearing loss groups significant differences were measured with L_nn_ABR (p < 0.05) with a mean 7.5 dB underestimation of PTA.
Although very similar, some significant differences were found when considering specific group of patients with different degrees of hearing loss.
Fuente: Auris Nasus Larynx