published_or_final_version / abstract / toc / Speech and Hearing Sciences / Master / Master of Science in Audiology

A number of studies have been made to examine several aspects of voice production in individuals with different types of hearing impairments. Most of the studies were made to explore the impact that hearing aids have for people with severe or congenital hearing impairment. So far it has been confirmed that there are changes regarding voice production in these individuals. A group that has not been investigated regarding voice production to a larger extent are hearing aid users with an acquired hearing impairment. In the present study the voice production of seven individuals, four men and three women, with a moderate acquired hearing impairment is examined. The individuals had an age span ranging from 55-71 years and had used hearing-aids for one year at the most. The participants were recorded as they completed three different tasks; reading aloud, spontaneous speech and production of sustained vowels. These tasks were performed twice; with and without hearing aids. An acoustic analysis of the recordings was performed in order to examine possible changes in mean fundamental frequency and vocal effort. Analysis on an individual level shows that throughout the different tasks, no participant demonstrated constant, audible differences regarding both fundamental frequency and vocal effort. However there were noticeable changes for a few participants in some of the tasks. Since the differences for most of the participants were negligible and inconsistent, no impact of the hearing aids or compensatory strategies was seen.

No description available.

A hearing impairment is one of the three leading causes of disability worldwide. It is estimated that 600 million people around the world have a hearing impairment, which affects their communication abilities, causes them to feel isolated and depressed, and impacts their economic situation. Because a decrease in the ability to hear is associated with getting older and life expectancy is increasing, the number of hearing impaired individuals is expected to increase. Much of the current research on adults with a hearing impairment focusses on a disabling hearing impairment, which is a loss of at least 40 dB HL or worse in the better ear. The research on a mild hearing impairment is predominantly focussed on children, specifically on educational effects. The aims of this study were to identify demographic, audiometric and quality of life differences between adults with a mild hearing impairment who adopt hearing aids and those who choose not to adopt hearing aids, and to measure clinical outcomes for adults with a mild hearing impairment who adopt hearing aids. Two groups of clients with a mild hearing impairment were compared. One group consisted of hearing aid adopters whilst the other group consisted of non-adopters. There was no significant difference between the groups in terms of demographic variables, such as age, gender or working status, or objective audiometric variables. We found a statistically significant difference between the groups in terms of subjective audiometric variables. Hearing aid adopters rated their hearing impairment worse than the non-adopters and were more inclined to change their current situation than the non-adopters. In addition, the adopters showed significant clinical improvement after wearing their hearing aids for an extended period of time.

The purpose of this study was to compare the use of behind-the-ear and in-the-ear hearing aids with a geriatric population. The aids were compared to see which type of aid the subjects could learn to use most easily and to see which type of aid they preferred to use.Subjects were fitted with acoustically similar in-the-ear and behind-the-ear hearing aids for alternate one week periods. The aids were evaluated in two ways: 1) A rating scale evaluating the subjects’ abilities to use the hearing aid (insert battery, insert aid, remove aid, remove battery, adjust volume) and 2) A questionnaire exploring the subjects’ reaction to care of hearing aid use and general aid preference.With respect to the rating scale, no significant differences were found. Subjects could perform the tasks covered with both types of aids. With respect to the questionnaire, significant differences were found in favor of the in-the-ear hearing aid. In general, the results of this study tend to indicate that geriatric subjects can handle in-the-ear hearing aids and behind-the-ear hearing aids with about equal success but that they have a clear preference for in-the-ear hearing aids.

This study investigates the listening environments of hearing aid users by employing the data logging capacity of their hearing aids. The idea that a hearing aid user's listening environments are important in prescribing desired hearing aid features has been discussed in the literature, however, investigation of listening environments has been limited in the past as it has relied mainly on subjective recordings. Data logging, the capacity of a hearing aid to continuously store information regarding time spent in different programs, listening environments, and microphone modes, is now available in a number of hearing aid models, and therefore provides an objective tool for studying a hearing aid user's listening environments. The data logging information from fifty-seven new hearing aid wearers, including 50 males and 7 females (mean age = 68 years, SD = 11.3), was obtained during the first routine clinic follow-up session for each individual. Measures of time spent in different listening environments, microphone modes, and overall sound levels, were analyzed. Hearing aid usage time was found to be highest in "Speech Only" situations (44.8%), followed by "Quiet" (26.7%), "Noise Only" (16.3%) and "Speech in Noise" (12.3%) situations. The majority of the hearing aid users' time was spent in "Surround" microphone mode (74.3%), followed in order by "Split" (22.3%) and "Full" (3.5%) directional modes. Results of two separate two-way ANOVAs revealed no significant age effect either on time spent in different listening environments [F(3,49) = 0.7, p= 0.5] or on time spent in different microphone modes [F(3,20) = 0.6, p= 0.6]. These findings provide empirical evidence regarding the general listening pattern of hearing aid users, which can be used as a starting point when troubleshooting problems experienced by hearing aid clients, or assessing a user's need for various hearing aid features.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2007. / Härtill 4 uppsatser.

Thesis (D. Phil.(Communication Pathology))--University of Pretoria, 2003. / Includes bibliographical references.

Thesis (M. Communication Pathology)--University of Pretoria, 2006. / Summary in English and Afrikaans. Includes bibliographical references.

Non-linear frequency compression (NLFC) hearing aids aim to deliver high-frequency sound to a better functioning, lower frequency region of the cochlea. Despite the widespread use of frequency lowering technology, it continues to be difficult to predict candidacy. Since the aim of NLFC is to improve high-frequency audibility, possible predictors of benefit may include high-frequency hearing thresholds. NLFC alters the harmonic relationship of speech, and it has frequently been proposed that auditory training may help users adapt to the distorted acoustic signal. The aim of this thesis was twofold: firstly, to identify audiometric predictors of benefit from NLFC, and secondly to explore the role of auditory training in adaptation to NLFC. The first study aimed to determine if outcome with NLFC was related to hearing thresholds. Twenty-one experienced adult hearing aid users, with mild-to-profound high-frequency hearing loss, completed speech recognition and self-report measures with NLFC enabled and disabled over 16 weeks. The additional benefit gained on phoneme detection and word recognition tasks with NLFC enabled was positively correlated with average high-frequency hearing loss. Additional benefit began to emerge as average high-frequency hearing thresholds exceeded 70 dB HL. There was some evidence of a ‘roll-off’ in additional benefit when hearing thresholds exceeded 100 dB HL. The second study aimed to identify which training method, if any, may help adaptation to NLFC. Forty young normally hearing adults were randomly allocated to one of four groups: a training group (sentence or consonant) or a control group (passive exposure or test-only). Training led to significant improvements on novel measures of speech recognition. Generalisation was limited to near transfer i.e. sentence training led to improved sentence recognition whilst consonant training led to improved consonant recognition. Improvements following passive exposure to frequency compressed sentences were equivalent to those achieved by active sentence training. Results from this second study suggest that auditory training may improve outcome for users of NLFC hearing aids, but passive exposure may be an important confounding variable. In the final study high-frequency focused sentence and consonant training was compared to sham training (passive exposure to a talking book). Twenty-six hearing-impaired adults who were new users of NLFC were allocated to either an auditory training or a sham training group. Measures of speech recognition and self-report benefit were administered before and after four weeks of home-based training. Auditory training significantly improved speech reception thresholds. In conclusion, benefit from NLFC was dependent on hearing thresholds; as hearing thresholds increased so did benefit. Participants with severe-to-profound high-frequency hearing loss gained most benefit from NLFC. Auditory training provided alongside NLFC significantly improved speech recognition in noise but changes to all other outcome measures were not significant.