Maximum Discrimination Score Research Articles

Verification of Hearing Aids by Comparing Real Ear Measurements and Word Recognition Scores

Background and Objectives In this study, we introduce our method of hearing aid (HA) verification using real ear measurement (REM). We verified HAs that have gone through the fitting program using speech mapping REM; we then compared the outcome with word recognition scores (WRS) to evaluate functional gain. Subjects and Method Fifty-six patients of sensorineural hearing loss (81 ears) were enrolled in the study. In REM, if the gap between the target gain of HA and real ear aided response (REAR) was less than 10 dB SPL, fitting was considered successful. In speech audiometry, unaided maximum discrimination score (PB max), unaided WRS at 65 dB HL and aided WRS at 65 dB HL were measured. By comparing PB max and aided WRS at 65 dB HL, patients were sorted into best (n=15), good (n=57), and poorly (n=9) aided groups and analyzed for the successes of fitting. Fitting was deemed unsuccessful if REAR was ≥10 dB SPL lower than the target value of HA.Results The mean aided WRS at 65 dB HL of best, good and poorly aided groups were 85.6%, 77.3%, and 54.2%, respectively. There were statistically significant differences between all groups (<i>p</i>=0.019, 0.001, 0.002). The success rates of HA fitting showed significant differences at 0.5, 0.75, 1, 4 kHz of 55 dB SPL (<i>p</i>=0.023, 0.005, 0.003, 0.014), and at 4 kHz of 65 and 75 dB SPL (<i>p</i>=0.004, 0.001). The high WRS group showed sufficient gain at many frequencies. Conclusion Well fitted HAs can provide sufficient increase in speech intelligibility. Using the speech mapping REM is a great method to verify fitting of HA.

Cochlear implantation in patient with Charcot-Marie-Tooth disease

Two patients with auditory neuropathy spectrum disorder (ANSD) considered to be associated with Charcot-Marie-Tooth (CMT) are reported. In case 1, a 23-year-old man presented with progressive bilateral sensorineural hearing loss (SNHL) from 10 years of age and was diagnosed with ANSD. He was later diagnosed with CMT by neurological testing. In case 2, a 16-year-old girl, the younger sister of the patient in case 1, presented with progressive SNHL with similar auditory findings since 6 years of age as those of her brother. Both cases underwent bilateral cochlear implantation. In case 1, the maximum discrimination score improved to 45% 24 months after the first side of cochlear implantation from 5% before the surgery. In case 2, the score was 5% 10 months after cochlear implant (CI) surgery from 0% before the surgery. CI treatment for CMT patients has been considered difficult because of both failure in synchronization of nerve conduction due to demyelination and axonal failure of the auditory nerve. Though slower progress compared to the average subset of patients receiving CI was seen, significant improvement was gradually observed in the present patients after bilateral cochlear implantations. CI is thus a viable option for rehabilitation of SNHL in CMT patients.

Effect of Binaural Hearing Aids on the Improvement of the Maximum Discrimination Score

両耳聴の意義に対する認識が高まり, 補聴器も人工内耳も可能であれば両耳聴を目指す方向に向かっている. 今回, 装用前の語音弁別能は不良であったが, 両耳装用後に実用レベルに達した症例について検討した. 耳鳴を主訴とした両側水平性感音難聴の2症例で, 語音弁別能は初診時左右それぞれ30～55%であったが, 1年後には両耳装用下の音場検査にて各々80,95%という結果が得られた. これは周波数ごとに圧縮を変更しながら十分なファンクショナルゲインを確保したことと, 優れた両耳聴効果に起因するところが大きいと思われる. そして, 補聴器の調整を適正に行い十分な聴能訓練を行うことで, 補聴器の効果をより発揮できると考える.

Decline of speech understanding in the hearing impaired elderly listeners who visited our hearing aid clinic

The aim of this study was to investigate distinctive change in the hearing impaired elderly listeners, especially about speech recognition. Subjects were 525 patients (235 males, 290 females), from 60 to 98 years of age who had visited the Hearing Aid Clinic of Otorhinolaryngology, National Center for Geriatrics and Gerontology Hospital, between June 2001 and December 2012. Pure-tone air conduction threshold determination was administered to each subject. The speech audiometry materials used to define speech discrimination ability were Japanese monosyllabic word lists, 67S word lists. Sex- and age-specific trends in maximum discrimination score (MDS) and rollover index (RI) were shown in this study. RI was computed by the formula (PBmax-PBmin)/PBmax. PBmax has almost the same meaning as MDS in Japan. PBmin represented the lowest PB score above the test intensity level of PBmax. Mean MDSs were 80.8% in their sixties, 75.3% in their seventies, 60.7% in their eighties, and 45.5% in their nineties. The rate of decrease in mean MDS per decade accelerated in the older generation. Mean RIs were 0.18 in patients in their sixties, 0.24 in their seventies, 0.30 in their eighties, and 0.30 in their nineties. It increased until the age of eighties. In the model 1, multiple logistic analyses were performed to examine the effect of age (in 10-year increments), sex and mean hearing levels in pure tone average of values at 500, 1000, 2000, 4000 Hz (in 10 dB increments) on the MDS < 60%. Significant associations were observed between MDS < 60% and age (odds ratio, 3.03; 95% confidence interval, 2.38 to 3.85), and mean hearing levels in pure tone average of values at 500, 1000, 2000, 4000 Hz (2.33; 2.03 to 2.68). Sex was not associated with MDS < 60%. In the model 2, multiple logistic analyses adjusted for age and sex were performed to examine the effect of hearing level at test frequencies of 125, 250, 500, 1000, 2000, 4000, and 8000 Hz (in 10 dB increments)on the MDS < 60%. Significant associations were observed between MDS < 60% and hearing level at 250 Hz (2.04; 1.44 to 2.89), and 2000 Hz (1.46; 1.16 to 1.83), and 4000 Hz(1.24; 1.02 to 1.50). These outcomes suggest that the important point in qualifying the fitting of hearing aid is to present the list words at an adequate sound pressure level for evaluation of speech understanding especially in the hearing impaired elderly listeners.

Residual hearing capacity of severely hearing-impaired subjects : Lamore P.J.J.;Verweij C.;Brocaar M.P.Acta Oto-Laryngol. Suppl. (1990) -/469 (7–15)

Speech reception functions (speech reception threshold and maximum discrimination score for phonemes) and auditory functions (hearing threshold, difference limens for intensity and frequency, temporal modulation threshold function, critical ratio and temporal integration) have been investigated in a group of severely hearing-impaired subjects (64 ears, median Fletcher Index of 80 dB). The results were separated into low-, middle- and high-frequency regions. The investigations were intended to describe and quantify the residual hearing capacities and the correlations between the different functions. It was found that the speech functions, the difference limen for frequency, the critical ratio and the time constant of temporal integration deteriorate gradually with increasing hearing loss. These functions show a relatively high mutual correlation in the low-frequency region and considerable scatter in the high-frequency part. The sensitivity for modulations and the difference limen for intensity were least affected. The results revealed that the residual capacity can be described by means of two independent factors: frequency discrimination at the higher frequencies and a decrease in processing efficiency of the system. The latter is dominated by the middle- and low-frequency hearing elements.

Residual Hearing Capacity of Severely Hearing-impaired Subjects.

Speech reception functions (speech reception threshold and maximum discrimination score for phonemes) and auditory functions (hearing threshold, difference limens for intensity and frequency, temporal modulation threshold function, critical ratio and temporal integration) have been investigated in a group of severely hearing-impaired subjects (64 ears, median Fletcher Index of 80 dB). The results were separated into low-, middle-and high-frequency regions. The investigations were intended to describe and quantify the residual hearing capacities and the correlations between the different functions. It was found that the speech functions, the difference limen for frequency, the critical ratio and the time constant of temporal integration deteriorate gradually with increasing hearing loss. These functions show a relatively high mutual correlation in the low-frequency region and considerable scatter in the high-frequency part. The sensitivity for modulations and the difference limen for intensity were least affected. The results revealed that the residual capacity can be described by means of two independent factors: frequency discrimination at the higher frequencies and a decrease in processing efficiency of the system. The latter is dominated by the middle-and low-frequency hearing elements.

鼓室形成術前後の語音聴力検査

The speech reception threshold and maximum discrimination score were analyzed in 158 patients with chronic otitis media before and after tympanoplasty.The air conduction threshold improved significantly in low and middle frequencies after tympanoplasty. The speech reception threshold also improved significantly, but the maximum discrimination score, did not change significantly.In the patients with improved speech reception threshold after tympanoplasty, the air conduction threshold was improved in the low and middle frequencies. In the same patients, however, there was no improvement in the high frequencies. On the other hand, in patients whose speech reception threshold was worsened after tympanoplasty, the air conduction threshold did not change in the low and middle frequencies and was aggravated in the high frequencies.In 60% of the patients whose air conduction threshold improved after tympanoplasty, the speech reception threshold also improved, while in only 20% of the patients whose air conduction threshold was aggravated after tympanoplasty, the speech reception threshold was also aggravated.These results suggest that both pure tone audiometry and speech audiometry are necessary to evaluate hearing differences before and after tympanoplasty.

５７Ｓ語表と５７語表との比較検討 中等度感音性難聴者における検討

The intelligibility difference between the 57-S List and the 57 List was studied using six intensity levels in 12 cases of moderate and moderately severe sensorineural hearing loss.The results were summarized as follows: (1) The maximum discrimination score showed no significant difference between the two lists. The intensity level of the maximum discrimination score was obtained at the condition of 30dB on both lists. (2) Intelligibility on the two lists improved about 40 percent when the intensity level increased from 0dB to 30dB. (3) The 57-S List showed about 10 percent better results than the 57 List under the conditions of lower intensity level compared with that of the maximum discrimination score. (4) In the discrimination score of consonants on the 57-S List, voiceless consonants were improved under the condition of 30dB and 20dB. Voiceless consonants, voiced consonants and semivowels were identified under the 10dB condition. As for nasal and vowels, there were no significant differences between the 57 List and 57S List.Therefore, the 57-S List is considered to be available instead of the 57 List as far as the items (3) and (4) mentioned above are concerned.

Investigations of the residual hearing capacity of severely hearing-impaired and profoundly deaf subjects.

Speech reception functions (maximum discrimination score for phonemes, speech reception threshold) and auditory functions (pure-tone audiogram, difference limens for frequency and intensity, temporal modulation transfer function, critical ratio and temporal integration) have been investigated in a group of severely hearing-impaired and deaf subjects (median Fletcher index: 80 dB), for different frequency regions (250, 1 000 and 2 000/4 000 Hz). The correlations between the different functions were calculated on the basis of characteristic numbers, derived from the originally measured functions, in the indicated frequency regions. The residual hearing capacities could be described best with two factors, one reflecting the distortion term in the speech reception threshold and the other representing the frequency discrimination for high-frequency tones. It was found that residual hearing capacities are present, at least up to a Fletcher index of 105 dB.

Audiological considerations in Ménière's disease.

The audiological findings in Ménière's disease are reviewed particularly in respect of loudness recruitment and speech discrimination loss. Although recruitment is pathognomonic of all cochlear lesions, certain distinguishing features are apparent in Ménière's disease which differ from those in other non-metabolic disorders of the cochlea. With mild degrees of hearing loss, recruitment appears to aid speech discrimination supporting the suggestion that it represents the ears adjustment to failing hearing. With more profound degrees of hearing loss, there is a linear inverse relationship between maximum discrimination score and hearing level. Actual hearing aid gains preferred by patients correlate well with those predicted from a consideration of recruitment curves.

Use of Performance-Intensity Functions for Diagnosis

Performance-intensity (PI) functions for phonetically balanced (PB) word lists were obtained for a group of normal listeners (27 ears), and for two groups of patients with cochlear (89 ears) and retrocochlear disorders (eight ears). Listeners with normal hearing or cochlear disorders exhibited mild to moderate reductions in discrimination score as the speech level was raised above the PB maximum. In contrast, patients with retrocochlear disorders showed a pronounced rollover phenomenon, characterized by a rapid decline in performance as the speech level was raised above the maximum discrimination score.

Speech Discrimination in Presbycusis

The purpose of this study was to explore the effects upon auditory sensitivity and discrimination, and to investigate the relationship between the several tests used in the evaluation at advanced ages.The speech reception threshold and the speech discrimination were tested with the Japanese test material List 57 AB. A comparative analysis of the articulation scores of the voiced and voiceless consonants revealed some interesting differences in the discrimination function.The results obtained were as follows:1. Auditory discrimination was generally poor when compared with pure tone hearing in presbycusis, but several cases showed better response for speech. Consequently, we considered the possibility of the auditory compensation in the brain for the speech hearing impairment.2. In presbycusis the threshold for the voiced consonants was many times somewhat better than that for the voiceless consonants, although the maximum discrimination score was better for the voiceless consona nts.3. The average articulation curve in presbycusis showed less steep than normal slope. It was significantly less steep in the severe cases.4. In environments of noise, loss of hearing due to presbycusis resulted in severe loss of discrimination of speech, particularly of voiceless consonants.