ABSTRACT
The Freiburger Speech Test (FST) has been the gold standard in speech testing by word recognition score in Germany for many years. Recently, it has been demonstrated that for an amount of 104 test-persons there is no significant deviation within the lists. The objective of this study was to determine the percentiles of the distinct measuring situations in quiet and with noise (e.g. applied in hearing aid fitting) and the average benefit using hearing aids. In this prospective study, 623 patients with SNHL and equipped with hearing aids for at least 3 months have been investigated by means of the Freiburger monosyllabic test (FBE) without and with hearing aids and in quiet or with noise (CCITT noise, 65/60 dB signal-noise ratio) in free field conditions at 65 dB to determine the ratio of intelligibility. To investigate the different diagnostic conditions a linear mixed model was applied. The dependent binary variable corresponds to the number of understood syllables. The average age of all subjects was about 72.6 years. The average rate of understanding in the FBE without hearing aids and in quiet was 38.5 %, with hearing aids and in quiet 67.7 %, without hearing aids and with noise 22.4 %, and with hearing aids and with noise 39.8 %. All results were presented with the depending confidence intervals. The extent of hearing loss and the quality of hearing aid fitting can be successfully measured using the FST in quiet and with background noise (CCITT noise). In quiet, an average hearing improving gain of 29.2 % points and with noise a gain of 17.4 % points could be estimated with a successful hearing aid fitting.
Subject(s)
Hearing Aids , Hearing Loss, Sensorineural/therapy , Noise , Aged , Aged, 80 and over , Audiometry, Speech , Female , Germany , Humans , Male , Middle Aged , Prospective Studies , Speech PerceptionABSTRACT
BACKGROUND: The Freiburg speech test has been the gold standard in speech audiometry in Germany for many years. Previously, however, this test had not been evaluated in assessing the effectiveness of a hearing aid in background noise. Furthermore, the validity of particular word lists used in the test has been questioned repeatedly in the past, due to a suspected higher variation within these lists as compared to the other word list used. PATIENTS AND METHODS: In this prospective study, two groups of subjects [normal hearing control subjects and patients with SNHL (sensorineural hearing loss) that had been fitted with hearing aid] were examined. In a first group, 113 control subjects with normal age- and gender-related pure tone thresholds were assessed by means of the Freiburg monosyllabic test under free-field conditions at 65 dB. The second group comprised 104 patients that had been fitted with hearing aids at least 3 months previously to treat their SNHL. Members of the SNHL group were assessed by means of the Freiburg monosyllabic test both with and without hearing aids, and in the presence or absence of background noise (CCITT-noise; 65/60 dB signal-noise ratio, in accordance with the Comité Consultatif International Téléphonique et Télégraphique), under free-field conditions at 65 dB. RESULTS: The first (control) group exhibited no gender-related differences in the Freiburg test results. In a few instances, inter-individual variability of responses was observed, although the reasons for this remain to be clarified. Within the second (patient) group, the Freiburg test results under the four different measurement conditions differed significantly from each other (p>0.05). This group exhibited a high degree of inter-individual variability between responses. In light of this, no significant differences in outcome could be assigned to the different word lists employed in the Freiburg speech test. CONCLUSION: The Freiburg monosyllabic test is able to assess the extent of hearing loss, as well as the effectiveness of a fitted hearing aid, in the presence or absence of background-noise (CCITT-noise). The present study could not evidence statistically significant differences in outcome when using the different word lists in this test battery.
