BACKGROUND AND OBJECTIVES: Clear speech is an effective communication strategy used in difficult listening situations that draws on techniques such as accurate articulation, a slow speech rate, and the inclusion of pauses. Although too slow speech and improperly amplified spectral information can deteriorate overall speech intelligibility, certain amplitude of increments of the mid-frequency bands (1 to 3 dB) and around 50% slower speech rates of clear speech, when compared to those in conversational speech, were reported as factors that can improve speech intelligibility positively. The purpose of this study was to identify whether amplitude increments of mid-frequency areas and slower speech rates were evident in Korean clear speech as they were in English clear speech. SUBJECTS AND METHODS: To compare the acoustic characteristics of the two methods of speech production, the voices of 60 participants were recorded during conversational speech and then again during clear speech using a standardized sentence material. RESULTS: The speech rate and long-term average speech spectrum (LTASS) were analyzed and compared. Speech rates for clear speech were slower than those for conversational speech. Increased amplitudes in the mid-frequency bands were evident for the LTASS of clear speech. CONCLUSIONS: The observed differences in the acoustic characteristics between the two types of speech production suggest that Korean clear speech can be an effective communication strategy to improve speech intelligibility.
Acoustics ; Rehabilitation ; Speech Acoustics ; Speech Intelligibility ; Speech Perception ; Voice

BACKGROUND AND OBJECTIVES: The purpose of this study was to identify differences between the dynamic ranges (DRs) of male and female speakers using Korean standard sentence material. Consideration was especially given to effects within the predefined segmentalized frequency-bands. MATERIALS AND METHODS: We used Korean standard sentence lists for adults as stimuli. Each sentence was normalized to a root-mean-square of 65 dB sound pressure level. The sentences were then modified to ensure there were no pauses, and the modified sentences were passed through a filter bank in order to perform the frequency analysis. Finally, the DR was quantified using a histogram that showed the cumulative envelope distribution levels of the speech in each frequency band. RESULTS: In DRs that were averaged across all frequency bands, there were no significant differences between the male and the female speakers. However, when considering effects within the predefined frequency bands, there were significant differences in several frequency bands between the DRs of male speech and those of female speech. CONCLUSIONS: This study shows that the DR of speech for the male speaker differed from the female speaker in nine frequency bands among 21 frequency bands. These observed differences suggest that a standardized DR of male speech in the band-audibility function of the speech intelligibility index may differ from that of female speech derived in the same way. Further studies are required to derive standardized DRs for Korean speakers.
Adult ; Female* ; Humans ; Male* ; Speech Intelligibility

OBJECTIVE: The objective of this study was to evaluate the degree of intelligible speech in workers wearing hearing protective devices and the differences in background noise type. METHODS: A total 82 shipyard company employees and normal hearing volunteers were recruited as subjects from a company in Ulsan: subjects were classified to the hearing-impaired group or to the control group according to hearing status. They were tested pure tone and speech audiometry in varying test environments including signal-to-noise ratio and background noise type in a headphone and in a free field environment. RESULTS: For both groups, the attenuation of hearing protective devices was greater at high frequencies. For the hearing-impaired group, speech discrimination scores differences between the unprotected and the protected ear were not significant between background noise type, when speech was presented at 65 dBA. However speech intelligibility in white noise background was lower than in the other background noise types when speech was presented at 75 dBA. CONCLUSIONS: Workers' speech intelligibility increased with an increasing signal-to-noise ratio. Speech intelligibility was also dependent on background noise type. Workers and their colleagues were trained to pronounce words more loudly and more clearly when they wearing hearing protective devices or other communication methods that do not use sound signal should be considered.
Audiometry, Speech ; Ear ; Ear Protective Devices ; Hearing ; Humans ; Noise ; Signal-To-Noise Ratio ; Speech Intelligibility ; Speech Perception

PURPOSE: The purpose of this study was to analyze the influence of palatal height on Korean vowels and speech intelligibility in Korean adults and to produce baseline data for future prosthodontic treatment. MATERIAL AND METHODS: Forty one healthy Korean men and women who had no problem in pronunciation, hearing, and communication and had no history of airway disease participated in this study. Subjects were classified into H, M, and L groups after clinical determination of palatal height with study casts. Seven Korean vowels were used as sample vowels and subjects' clear speech sounds were recorded using Multispeech software program on computer. The F1 and the F2 of 3 groupswere produced and they were compared. In addition, the vowel working spaces of 3 groups by /a/, /i/, and /u/ corner vowels were obtained and their areas were compared. Kruskal-Wallis test and Mann-Whiteny U test were used as statistical methods and P < .05 was considered statistically significant. RESULTS: There were no significant differences in formant frequencies among 3 groups except for the F2 formant frequency between H and L group (P = .003). In the analysis of vowel working space areas of 3 groups, the vowel working spaces of 3 groups were similar in shape and no significant differences of their areas were found. CONCLUSION: The palatal height did not affect vowel frequencies in most of the vowels and speech intelligibility. The dynamics of tongue activity seems to compensate the morphological difference.
Adult ; Female ; Hearing ; Humans ; Male ; Phonetics ; Prosthodontics ; Speech Intelligibility ; Tongue

PURPOSE: The purpose of this study was to compare men with women in terms of speech intelligibility, to investigate the validity of objective acoustic parameters related with speech intelligibility, and to try to set up the standard data for the future study in various field in prosthodontics. MATERIAL AND METHODS: Twenty men and women were served as subjects in the present study. After recording of sample sounds, speech intelligibility tests by three speech pathologists and acoustic analyses were performed. Comparison of the speech intelligibility test scores and acoustic parameters such as fundamental frequency, fundamental frequency range, formant frequency, formant ranges, vowel working space area, and vowel dispersion were done between men and women. In addition, the correlations between the speech intelligibility values and acoustic variables were analyzed. RESULTS: Women showed significantly higher speech intelligibility scores than men and there were significant difference between men and women in most of acoustic parameters used in the present study. However, the correlations between the speech intelligibility scores and acoustic parameters were low. CONCLUSION: Speech intelligibility test and acoustic parameters used in the present study were effective in differentiating male voice from female voice and their values might be used in the future studies related patients involved with maxillofacial prosthodontics. However, further studies are needed on the correlation between speech intelligibility tests and objective acoustic parameters.
Acoustics ; Female ; Humans ; Male ; Phonetics ; Prosthodontics ; Speech Intelligibility ; Voice

BACKGROUND AND OBJECTIVES: In this paper, rehabilitation of voice after total laryngectomy has been suggested through the correct estimation and simulation of patients' vocal tract. Material and Methods: The author studied the shape of vocal tract during the phonation of five Korean vowels /u, o, a, e, i/ in tracheoesophageal shunt patients by magnetic resonance images (MRI). The same vocal tract was determined in each vowels from MRI. First, speech data produced by them were analyzed and also checked for speech intelligibility. Then the author tried to synthesize vowels from the vocal tract area of each vowels and from the expanded pharyngeal section of the vocal tract. RESULTS: The obtained results were as follows: 1) The sounds of /a/, /e/, /i/ were similar to natural sounds in actual patients' speech. The sound of /o/ was heard as /sigma/. The sound of /u/ was heard as strained /u/. 2) The synthesized vowels of /a/, /e/ from MRI were heard as natural sounds. The sounds of /u/, /o/, /i/ were heard as other sounds. 3) The synthesized vowel by the expanded pharyngeal section of 3 times in vowel /o/ was more naturally heard than that of 2 times. The synthesized vowel from Formfrek was more naturally heard than that from AreatoFormant. CONCLUSION: In conclusion, some of the synthesized sounds from MRI disagrees with the actual sounds produced by the subjects. This could be best identified by the synthesis from the area data. Future MRI studies should consider this problem for more accurate measurements. Also, pharyngeal areas with varied sizes should be experimented to secure better speech output because the correct shapes of vocal tract ensures correct vowel pronunciation.
Humans ; Laryngectomy* ; Magnetic Resonance Imaging ; Phonation ; Rehabilitation ; Speech Intelligibility* ; Voice

OBJECTIVES: Directional microphone technology can enhance the speech intelligibility and listening comfort of listeners with hearing impairment. The main aim of this study is to investigate and compare the benefit derived by listeners with severe hearing loss from directional microphone technology with that derived by listeners with moderate hearing loss. METHODS: The acceptable noise levels (ANLs) of two groups of listeners with moderate or severe hearing impairment (17 subjects in each group) were measured under unaided, omnidirectional-baseline-aided, and directional-aided conditions. RESULTS: Although the absolute ANL of the listeners in the severe hearing loss group was significantly higher than that of the listeners in the moderate hearing loss group, their derived benefit was equivalent to that derived by the listeners in the moderate hearing loss group. ANL and hearing loss degree were significantly related. Specifically, the ANL increased with the severity of hearing loss. CONCLUSION: Directional microphone technology can provide the benefits of listening comfort to listeners with severe hearing loss.
Hearing Aids ; Hearing Loss* ; Hearing* ; Noise* ; Speech Intelligibility

BACKGROUND AND OBJECTIVES: In auditory tests, several kinds of background noises have been used ; multitalker babble noise, speech noise and white noise, etc. The aim of the present study was to evaluate the effects of different types of background noises on speech intelligibility. SUBJECTS AND METHOD: Sixty volunteers having pure-tone thresholds less than 25 dB HL participated in this study. Their ages ranged from teens to sixties with ten subjects in each age group (mean age=40+/-15.4 years, m=25, f= 35) We used three types of background noises used in this study ; multitalker babble noise using the voices of Korean speakers, speech noise using English sentences and white noise. Fifty percent recognition of signal to noise ratios (SNRs) and word recognition scores (WRSs) at -10, -5, 0 dB SNR conditions were measured at 70 dB HL of noise intensity. RESULTS: Fifty percent recognition of SNRs on multitalker babble, speech and white noise were -12.4+/-1.4 dB, -13.7+/-1.0 dB and -15.8 +/-1.0 dB, respectively and they were significantly different each other (p< 0.05). Multitalker babble noise generated the lowest WRSs followed by speech noise and then white noise (p< 0.05). CONCLUSION: These results support that multitalker babble noise using the voices of Korean speakers influence on normal listener's speech intelligibility more than speech noise from English sentences or white noise
Adolescent ; Hearing ; Humans ; Noise ; Signal-To-Noise Ratio ; Speech Intelligibility ; Voice

OBJECTIVES: Speech intelligibility is severely affected in children with congenital profound hearing loss. Hypernasality is a problem commonly encountered in their speech. Auditory information received from cochlear implants is expected to be far superior to that from hearing aids. Our study aimed at comparing the percentages of nasality in the speech of the cochlear implantees with hearing aid users and also with children with normal hearing. METHODS: Three groups of subjects took part in the study. Groups I and II comprised 12 children each, in the age range of 4-10 years, with prelingual bilateral profound hearing loss, using multichannel cochlear implants and digital hearing aids respectively. Both groups had received at least one year of speech therapy intervention since cochlear implant surgery and hearing aid fitting respectively. The third group consisted of age-matched and sex-matched children with normal hearing. The subjects were asked to say a sentence which consisted of only oral sounds and no nasal sounds ("Buy baby a bib"). The nasalance score as a percentage was calculated. RESULTS: Statistical analysis revealed that the children using hearing aids showed a high percentage of nasalance in their speech. The cochlear implantees showed a lower percentage of nasalance compared to children using hearing aids, but did not match with their normal hearing peers. CONCLUSION: The quality of speech of the cochlear implantees was superior to that of the hearing aid users, but did not match with the normal controls. The study suggests that acoustic variables still exist after cochlear implantation in children, with hearing impairments at deviant levels, which needs attention. Further research needs to be carried out to explore the effect of the age at implantation as a variable in reducing nasality in the speech and attaining normative values in cochlear implantees, and also between unilateral versus bilateral implantees.
Acoustics ; Child ; Cochlear Implantation ; Cochlear Implants ; Hearing ; Hearing Aids ; Hearing Loss ; Humans ; Speech Intelligibility ; Speech Therapy

OBJECTIVETo investigate the development of early auditory capability and speech perception in the prelingual deaf children after cochlear implantation, and to study the feasibility of currently available Chinese assessment instruments for the evaluation of early auditory skill and speech perception in hearing-impaired children.

METHODSA total of 83 children with severe-to-profound prelingual hearing impairment participated in this study. Participants were divided into four groups according to the age for surgery: A (1-2 years), B (2-3 years), C (3-4 years) and D (4-5 years). The auditory skill and speech perception ability of CI children were evaluated by trained audiologists using the infant-toddler/meaningful auditory integration scale (IT-MAIS/MAIS) questionnaire, the Mandarin Early Speech Perception (MESP) test and the Mandarin Pediatric Speech Intelligibility (MPSI) test. The questionnaires were used in face to face interviews with the parents or guardians. Each child was assessed before the operation and 3 months, 6 months, 12 months after switch-on.

RESULTSAfter cochlear implantation, early postoperative auditory development and speech perception gradually improved. All MAIS/IT-MAIS scores showed a similar increasing trend with the rehabilitation duration (F=5.743, P=0.007). Preoperative and post operative MAIS/IT-MAIS scores of children in age group C (3-4 years) was higher than that of other groups. Children who had longer hearing aid experience before operation demonstrated higher MAIS/IT-MAIS scores than those with little or no hearing aid experience (F=4.947, P=0.000). The MESP test showed that, children were not able to perceive speech as well as detecting speech signals. However as the duration of CI use increased, speech perception ability also improved substantially. However, only about 40% of the subjects could be evaluated using the most difficult subtest on the MPSI in quiet at 12 months after switch-on. As MCR decreased, the proportion of children who could be tested using the MPSI reduced.

CONCLUSIONSWithin one year after CI, children develop early auditory and speech perception capabilities with time. Chinese versions of the IT-MAIS/MAIS, MESP and MPSI are useful instruments to document early auditory and speech perception skills in children after CI implantation.

Child, Preschool ; Cochlear Implantation ; Deafness ; surgery ; Hearing Aids ; Humans ; Infant ; Speech Intelligibility ; Speech Perception ; Surveys and Questionnaires