Application of sentence tests in the investigation of speech intelligibility in quiet and noise in adult CI recipients supported with a hearing aid

The investigations of speech intelligibility were carried
out for 9 patients with a cochlear implant (CI), 1 male and 8 females, aged
18-69 (mean 41). In all cases deafness was recognized as postlingual. All
patients were using the hearing aid (HA) on the ear opposite to the CI. The
novelty of this work consisted in the application of new Polish sentence tests
in the evaluation of the effect of supporting electrical hearing with a HA in
noise conditions. The sentence tests (developed at the Institute of Acoustics,
Adam Mickiewicz University in Poznań - European Union Project HEARCOM) were
presented to patients in quiet and in noise conditions (speech bubble noise).
The speech intelligibility was determined in two cases: when transmission was
only via the CI and when the HA was also used. The presentation of tests was
conducted for three angles (0o, -90o and +90o) in relation to the patient's
head. The value of SRT (Speech Reception Threshold) was determined for the tests
carried out in noise conditions. The improvement of the speech intelligibility
was affirmed when the process of hearing via the CI was supported with a HA. The
particularly essential difference was observed for the angle of +90o (HA-side).
The results obtained in the investigations show that acoustic compensation in
the range of the remaining audibility field to a great degree supports
electrical hearing. This conclusion can be an important contribution to the
application of the HA on the side opposite to the CI, especially in the noisy
environment.