The purpose of this report was to investigate the sound environments in lecture halls at Umeå University and to assess to whether the sound environments in these lecture halls are satisfactory and whether have good speech intelligibility or not. Based on a web survey, a number of lecture halls were selected for this investigation, namely Hörsal A, Hörsal C, N280, KB.F3.01, Ma121, KB.E3.01, N340 and N335. Assessing room acoustics includes many relevant parameters, therefore a delimitation has been made. Only installation noise, reverberation time and speech intelligibility have been investigated. The methods followed established Swedish standards i.e SS-EN ISO 16032:2004 for installation noise,” integrated impulse response method” SS-EN ISO 3382:2:2008/AC:2009 for reverberation time and direct FULL STI (speech transmission index) IEC 60268-16:2011 for speech intelligibility. An ocular inspection was carried out of all the selected lecture halls. The result from the STI test showed that all the lecture halls except for Hörsal A have a good speech intelligibility, if the audience has normal hearing and they are listening to a lecture in their native language. In Hörsal A there are three measuring positions that fails to achieve the threshold for good speech intelligibility. The conclusion for all of the measurements that has been made are that Ma121 and KB.E3.01 has a satisfactory sound environment and that Hörsal A, Hörsal C, N280, KB.F3.01, N340 and N335 need actions to improve their sound environment so they can fulfil the benchmarks in Swedish public health authority regulations in FoHMFS 2014:13 and/or SS 25268:2007.

Parkinson's disease is a degenerative neurological condition which affects motor control, in almost all cases involving speech, and is frequently of many years duration. Much is known about speech production but less of the psychosocial consequences of the speech impairment (dysarthria). Accounts of people with dysarthria have shown that its impact on quality of social participation can be varied and profound. However, level of participation has not been investigated. Reduction in social activity and social networks has been found following onset of other neurogenic communication disorders. In Parkinson's disease there is some evidence of social activity reduction but this has not been studied in relation to severity of dysarthria. Social anxiety has been found to be raised in speakers with other speech production impairments and this may be a contributor to reduction in social engagement. Investigation of social variables is of importance in understanding relationships within a biopsychosocial model of health which underpins intervention for therapies for communication disorders. Aims The study aimed to investigate the impact of dysarthria on social participation and whether presence of dysarthria in Parkinson's disease (PD) resulted in changes to social anxiety, social networks and social activity. It further sought to investigate whether severity of dysarthria resulted in changes to the same variables. Method A group of 43 mild-moderately dysarthric speakers with PD were recruited. Exclusion criteria were applied to control for cognitive impairment, depression, apathy, movement disability and co-occurring neurological and communication impairment. A group of 30 non-neurologically impaired participants were recruited matched for age, sex, socioeconomic status and educational attainment. Participants with PD were further grouped using measures of sentence intelligibility and motor speech impairment into higher and lower functioning groups. All participants completed a social anxiety questionnaire, a social activity checklist and detailed their social network. Group data were compared to address the research questions. Semi-structured interviews were carried out with all participants to explore change to social life and perceptions of causes of change. Results Participants reported a range of changes to interaction and social engagement arising from speech and other impairments and also from intra and interpersonal contextual factors. Quantitative data showed that presence of dysarthria was associated with social anxiety and avoidance but not changes to social activity level or social network size. Greater severity of dysarthria was associated with deterioration in social activities and social network. There was wide individual variation on these variables. Outcomes Impact of dysarthria may be significant and unrelated to severity of impairment and satisfaction with level of activity is low in dysarthric speakers. Mild - moderately dysarthric speakers with PD may experience social anxiety in particular types of social situation. Moderately dysarthric speakers may experience loss of social capital in terms of quantitative changes in social networks and social activities. Motor speech impairment was a better predictor of social functioning than intelligibility in this sample. It is possible that a threshold for change lies at a more severe level of speech involvement. How speakers with PD perceive and experience their social interactions is discussed and limitations to the research are considered. The implications of the findings are discussed in relation to the ICF framework and the concept of social capital.

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<p>This Master’s thesis presents results from two clinical hearing aid studies. Wide dynamic range compression (WDRC), a hearing aid amplification algorithm widely used in the hearing aid industry, is compared against a novel hearing aid called the Neuro-Compensator (NC), which employs a neural-based amplification algorithm based on a computational model of the auditory periphery. The NC strategy involves preprocessing an incoming auditory signal, such that when the signal is presented to a damaged cochlea, auditory nerve output is reconstructed to look similar to the auditory nerve output of a healthy cochlea for the original auditory signal. The NC and WDRC hearing aid technologies are compared across a multitude of auditory domains. Objective measures of speech intelligibility in quiet and in noise, music perception, sound localization, and subjective measures of sound quality are obtained. It was hypothesized that the NC would restore more normal auditory abilities across auditory domains, due to its proposed strategy of restoring more normal auditory nerve output. Results from the clinical hearing aid studies quantified domains in which the NC was superior to WDRC, and vice versa.</p> / Master of Science (MSc)

Researchers have long known that general aviation (GA) aircraft exhibit some of the most intense and potentially damaging sound environments to a pilot's hearing. Yet, another potentially more ominous result of this noise-intense environment is the masking of the radio communications. Radio communications must remain intelligible, as they are imperative to the safe and efficient functioning of the airspace, especially the airspace surrounding our busiest airports, Class B and Class C. However, the high amplitude, low frequency noise dominating the GA cockpit causes an upward spreading of masking with such inference that it renders radio communications almost totally unintelligible, unless the pilot is wearing a communications headset. Even with a headset, some researchers have stated that the noise and masking effects overcome the headset performance and still threaten the pilot's hearing and overall safety while in the aircraft. In reaction to this situation, this experiment sought to investigate the effects which active noise reduction (ANR) headsets have on the permissible exposure levels (PELs), speech intelligibility, workload, and ultimately the pilot's performance inside the cockpit. Eight instrument-rated pilot participants flew through different flight tasks of varying levels and types of workload embedded in four 3.5 hour flight scenarios while wearing four different headsets. The 3.5 hours were considered long duration due the instrument conditions, severe weather conditions, difficult flight tasks, and the fatiguing effects of a high intensity noise environment. The noise intensity and spectrum in the simulator facility were specifically calibrated to mimic those of a Cessna 172. Speech intelligibility of radio communications was modified using the Speech Transmission Index (STI), while measures of flight performance and workload were collected to examine any relationships between workload, speech intelligibility, performance, and type of headset. It is believed that the low frequency attenuation advantages afforded by the ANR headset decreased the signal-to-noise ratio, thereby increasing speech intelligibility for the pilot. This increase may positively affect workload and flight performance. Estimates of subjective preference and comfort were also collected and analyzed for relevant relationships. The results of the experiment supported the above hypotheses. It was found that headsets which incorporate ANR technology do increase speech intelligibility which has a direct inverse influence on workload. For example, an increase in speech intelligibility is seen with a concomitant decrease in pilot workload across all types and levels of workload. Furthermore, flight task performance results show that the pilot's headset can facilitate safer flight performance. However, the factors that influence performance are more numerous and complex than those that affect speech intelligibility or workload. Factors such as the operational performance of the communications system in the headset, in addition to the ANR technology, were determined to be highly influential factors in pilot performance. This study has concluded that the pilot's headset has received much research and design attention as a noise attenuation device. However, it has been almost completely overlooked as a tool which could be used to facilitate the safety and performance of a general aviation flight. More research should focus on identifying and optimizing the headset components which contribute most to the results demonstrated in this experiment. The pilot's headset is a component of the aviation system which could economically improve the safety of the entire system. / Ph. D.

This thesis presents a study of several algorithms for enhancing speech degraded by additive noise in mobile cellular communications. The primary goal of this multi-stage study was to examine adaptive noise cancellation techniques in which one microphone is used to measure the speech plus noise signal and another microphone is used to form an estimate of the interfering background noise. The first stage of this research project involved the design and operation of a measurement system to gather dual channel audio samples in mobile radio environments for use in testing adaptive noise cancellation algorithms developed at Northeastern University. In the second phase of this research, several adaptive algorithms were used to implement noise cancellation systems which were applied to the measured speech signals. In the third phase of this research, several of the adaptive noise cancellation algorithms are compared and additional speech enhancement techniques are investigated. / Master of Science

This study evaluates a method for determining the quality of synthetic speech systems. The method involves the use of an auditory lexical decision task to assess the quality of synthetic speech generators relative to each other and to natural speech by using reaction time differences and error rates. Seven voices were evaluated; four synthesizers provided six voices (DECtalk 1.8 Perfect Paul, DECtaik 1.8 Beautiful Betty, DECtaik 2.0 Perfect Paul, DEC talk 2.0 Beautiful Betty, Votrax Personal Speech, Votrax Type'n'Talk) and natural speech provided the seventh voice. Both reaction times and error rates were higher for the low quality synthetic speech systems. The results document that the DECtalk can currently be considered a high quality synthesizer and that the Personal Speech and the Type'n'Talk can be considered low quality synthesizers. The results obtained by using this method can be explained by use of the Activation-Verification model (Paap, McDonald, Schvaneveldt, and Noel, 1986). Within the framework of this model, the results of this study suggest that the verification phase is the bottle-neck in processing words produced by synthetic speech generators. This interpretation suggests that by emphasizing the differences between different phonemes, to make them more uniquely identifiable, rather than concentrating on making them more "natural" might lead to improved results with synthesized speech. / Master of Science

Recent improvements in speech technology have made synthetic speech a viable I/O alternative. However, little research has focused on optimizing the various speech parameters which influence system performance. This study examined the effects of speech rate, message repetition, and the placement of information in a message. Briefly, subjects heard messages generated by a speech synthesizer and were asked to transcribe what they had heard. After entering each transcription, subjects rated the perceived difficulty of the preceding message, and how confident they were of their response. The accuracy of their response, system response time, and response latency were recorded. Transcription accuracy was best for messages spoken at 150 or 180 wpm and for messages repeated either twice or three times. Words at the end of messages were transcribed more accurately than words at the beginning of messages. Response latencies were fastest at 180 wpm with 3 repetitions and rose as the number of repetitions decreased. System response times were shortest when a message was repeated only once. The subjective certainty and difficulty ratings indicated that subjects were aware of errors when incorrectly transcribing a message. These results suggest that a) message rates should lie below 210 wpm, b) a repeat feature should be included in speech interface designs, and c) important information should be contained at the end of messages. / Master of Science