Mitochondrial deficiencies are present in limb skeletal muscle fibers throughout normal aging and can increase with accumulated exposure to reactive oxide species. Exogenous sources of reactive oxide species include cigarette smoke and other environmental toxins. Intrinsic laryngeal muscles are directly exposed to inhaled toxins which may increase the percentage of cytochrome c oxidase deficient fibers over time. Serial sections of posterior cricoarytenoid and control strap muscle were harvested post laryngectomy from 10 males age 54-78 years old. Cytochrome c oxidase, succinate dehydrogenase, and modified Gomori trichrome stains were used to determine the percentage of type I fibers with cytochrome c oxidase deficiency. Staining with myosin antibodies was used to determine fiber type. The posterior cricoarytenoid muscle contained a significantly higher percentage of type I fibers with cytochrome c oxidase deficiency (p=.002, t = 4.939) compared to the control strap muscle. The percentage of cytochrome c oxidase deficient fibers was also significantly correlated (r = +.851; p < .01) with age in posterior cricoarytenoid muscle. The percentage of type I fibers with cytochrome c oxidase deficiency increases with age in the posterior cricoarytenoid muscle and may be due to the accumulated exposure to reactive oxide species over time.

The role of exercise in vocal fold wound healing has been overlooked. Data from numerous other systems suggest a positive role of tissue mobilization to facilitate optimal wound healing and biomechanically superior tissue. The current study sought to investigate the potential role of mechanical signaling to attenuate the inflammatory and alter the synthetic properties of fibroblasts cultured from the vocal folds. Vocal fold fibroblasts were subjected to one of four conditions: no treatment, IL-1â alone, mechanical stress alone, or mechanical stress plus IL-1â. Results suggest that mechanical stress may limit the inflammatory phenotype of vocal fold fibroblasts in the short-term (4 hours), but not in the long-term (24 hours). In fact, 24 hours of mechanical stress may actually increase the inflammatory response. In addition, neither IL-1â nor mechanical stress had an effect on vocal fold fibroblast synthesis of extracellular matrix proteins. As a potential explanation for the current findings, it is hypothesized that the vocal folds may be more resilient to mechanical stress given the inherently stressful environment associated with phonation.

An important purpose of hearing is to aid communication. Because hearing-in-noise is of primary importance to individuals who seek remediation for hearing impairment, it has been the primary objective of advances in technology. Directional microphone technology is the most promising way to address this problem. Another important role of hearing is localization, allowing one to sense ones environment and feel safe and secure. The properties of the listening environment that are altered with directional microphone technology have the potential to significantly impair localization ability. The purpose of this investigation was to determine the impact of listening with directional microphone technology on individuals self-perceived level of localization disability and concurrent handicap. Participants included 57 unaided subjects, later randomly assigned to participate in one of three aided groups of 19 individuals each, who used omni-directional microphone only amplification, directional microphone only amplification, or toggle-switch equipped hearing aids that allowed user discretion over the directional microphone properties of the instruments. Comparisons were made between the unaided group responses and those of the subjects after having worn amplification for three months. Additionally, comparisons between the directional microphone only group responses and each of the other two aided groups responses were made. No significant differences were found. Hearing aids with omni-directional microphones, directional-only microphones, and those that are equipped with a toggle-switch, neither increased nor decreased the self-perceived level of ability to tell the location of sound or the level of withdrawal from situations where localization ability was a factor. Concurrently, directional-microphone only technology did not significantly worsen or improve these factors as compared to the other two microphone configurations. Future research should include objective measures of localization ability using the same paradigm employed herein. If the use of directional microphone technology has an objective impact on localization, clinicians might be advised to counsel their patients to be careful moving in their environment even though they do not perceive a problem with localization. If ultimately no significant differences in either objective or subjective measures are found, then concern over decreases in quality of life and safety with directional microphone use need no longer be considered.

This study examined the hypothesis that cognitive resources may be involved in swallowing. The approach involved a dual-task, reaction time (RT) paradigm with 10 healthy, non-impaired (NI) control participants and 10 participants in early to middle stages of Parkinsons disease (PD). First, baseline measures were obtained for durations of anticipatory phase and oropharyngeal phase during swallowing and RTs to non-word, auditory stimuli. Next, a dual-task was introduced requiring participants to swallow 5 ml of water from a cup while listening for a target non-word presented auditorily during anticipatory or oropharyngeal phases. Target stimuli were randomized across 19 baseline/single-task and 19 dual-task trials. For the single-task data, repeated measures analyses of variance were used to assess differences in (a) durations of the anticipatory phase across trials within and between participant groups; (b) durations of the oropharyngeal phase across trials within and between participant groups; and (c) durations of reaction times across trials within and between groups. For the dual-task data, analyses of variance were used to assess differences in (a) durations of the anticipatory phase between baseline/single-task and dual-task conditions; (b) durations of the oropharyngeal phase between baseline/single-task and dual-task conditions; and (c) durations of reaction times between baseline/single-task and dual-task conditions for each of the two swallowing phases. Results showed slowed swallowing and RTs in participants with PD compared to controls in both anticipatory and oropharyngeal phases of swallowing. This effect was largely carried by participants in more severe, mid-stage disease as compared to early disease. The anticipatory phase was more affected than the oropharyngeal phase, suggesting that cognitive demands may be greater for that phase. Swallowing durations were similar for NIs and participants in early stage PD, underscoring the strength and persistent nature of swallowing.

Abstract The present study sought (1) to determine if any evidence could be found of an influence of clinical language on self-efficacy for voice in adults with voice problems; and (2) to determine the number of subjects that would be required to undertake future large-scale study around this question, if warranted, based on effect sizes determined in the present investigation. The study¡¦s relevance has to do with prior concerns raised in the literature that common clinical language in voice care¡Xspecifically language indicating vocal ¡§abuse and misuse¡¨ as causal factors in selected voice disorders--has potential to harm self-efficacy for voice, which in turn may compromise patient compliance with treatment and thus clinical outcome (Verdolini, 1999). Fourteen teachers with self-reported voice disorders of unknown etiology were recruited as participants. Subjects were randomly assigned to one of two 15-min standardized, videotaped educational exposures by an unbiased clinician who was unaware of the experimental questions. One exposure described the origins of common voice problems in teachers in terms of vocal ¡§abuse/misuse¡¨ (N=7). The other exposure described the problems in terms of ¡§phonotraumatic behaviors and muscular tension¡¨ (N=7). Before and immediately after exposures, subjects completed a visual analogue scale Voice Self-Efficacy Questionnaire that was specially designed for the study, that assessed situation-neutral self-efficacy for voice. Psychometric evaluation of the tool indicated strong intra-rater and test-retest reliability (r d. 99; r d .78 respectively). The groups were also found to have no significant differences between them at the pre-test level, thus showing that amount of change on the post-test Voice Self-Efficacy Questionnaire were not influenced by individual subject differences on the pre-test. More conceptually interesting, binomial tests indicated that the majority of responses to self-efficacy questions reliably increased pre- to post exposure in the ¡§phonotrauma/muscle tension¡¨ (20/28 responses; p < .05), whereas no reliable change in scores was seen in the ¡§abuse/misuse¡¨ group (11/28 responses increased; non-significant). A Chi-Square test was conducted, and as with the binomial test, found a statistical difference between the 11 increased/28 possible self-efficacy responses of the ¡§abuse/misuse¡¨ group, and the 20/28 increased self-efficacy responses of the ¡§phonotrauma¡¨ group to the < .05 level. Results provide preliminary support for the hypothesis that clinical exposure to ¡§abuse/misuse¡¨ language may harm patients¡¦ self-efficacy for voice, not necessarily by decreasing pre-exposure self-efficacy but by compromising increases in self-efficacy that may normally be expected with patient education, as reported for other domains. The issue of self-efficacy for voice should be pursued in larger-scale studies in other laboratories. Effect sizes based on the present data indicated that at least 20 subjects per group (N=40 total) would be required to assess the effects of the noted terminology on voice-related self-efficacy shifts parametrically, using a similar experimental design.

The present study was designed to compare lexical decision latencies in visual and auditory modalities to three word types: (a) words that are inconsistent with two information sources, orthography and semantics (i.e., heterographic homophones such as bite/byte), (b) words that are inconsistent with one information source, semantics (i.e., homographic homophones such as bat), and (c) control words that are not inconsistent with any information source. Participants (N = 76) were randomly assigned to either the visual or auditory condition in which they judged the lexical status (word or nonword) of 180 words (60 heterographic homophones, 60 homographic homophones, and 60 control words) and 180 pronounceable nonsense word foils. Results differed significantly in the visual and auditory modalities. In visual lexical decision, homographic homophones were responded to faster than heterographic homophones or control words, which did not differ significantly. In auditory lexical decision, both homographic homophones and heterographic homophones were responded to faster than control words. Results are used to propose potential modifications to the Cooperative Division of Labor Model of Word Recognition (Harm & Seidenberg, 2004) to enable it to encompass both the visual and auditory modalities and account for the present results.

Based predominantly on semantic priming studies with divided visual field (DVF) presentation, current models of hemispheric differences in word semantic processing converge on a proposal that left hemisphere (LH) processes focus word meanings to their core by inhibiting less related meanings, whereas right hemisphere (RH) processes keep less related meanings active. The inhibition process supported by LH processing is assumed to apply to two distinct semantic processes: (a) narrowing of a single word meaning (inhibition of less related features and words), and (b) elimination of incompatible/ conflicting meanings of an ambiguous word. Semantic priming studies investigating hemispheric differences in these two processes have relied on associated prime-target pairs, which might have been problematic for two reasons. First, association might reflect lexical co-occurrence of word forms rather than effects of semantic relatedness; therefore, these studies might have confounded lexical and semantic priming effects. Second, in studies of ambiguous words dominant items were strongly associated whereas subordinate items were weakly associated; therefore, these studies confounded dominance and degree of relatedness. To address these confounds, this study conducted two semantic priming experiments with central prime presentation, DVF presentations for targets, and a 750 ms SOA. Experiment 1 investigated the effect of degree of semantic similarity on priming, using non-associated, prime-target pairs that were controlled for lexical co-occurrence. Experiment 2 investigated effects of meaning dominance on priming with non-associated prime-target pairs. Results are consistent with high-similarity priming for left visual field (lvf) and possibly for right visual field (rvf) targets, and with high-dominance priming for rvf and lvf targets, suggesting that LH (and RH) processes mediate effects of semantic similarity and dominance. However, priming effects in both experiments were very small. Thus, priming effects might have reflected that prime-target relatedness was less than expected, indicating that LH processing does not inhibit less related meanings, which is consistent with other studies using central primes. Additionally/ alternatively, larger priming effects in other studies might derive mainly from association rather than semantic similarity. Finally, the small priming effects could be due to some aspect of the experimental procedure that might have made these experiments less sensitive to semantic priming.

Although it is generally acknowledged that sensory feedback is required to fine tune movement patterns, its role in coordinative dynamics has received less attention. Experiment 1 investigated the role of visual and auditory feedback on 0º and 180º relative phase patterns at increasing frequency of oscillation for a bimanual limb task. The dependent variables were mean error of relative phase and standard deviation of relative phase. Results indicated that the visual and auditory feedback conditions did not influence the accuracy and the variability in performance of the 2 relative phase patterns, whereas increasing frequency influenced the performance of the 180º relative phase pattern, but not the 0º relative phase pattern. Experiment 2 investigated the role of auditory feedback on breathy, normal, and pressed voice qualities at increasing fundamental frequency for a voice coordination task. The dependent variables were mean of laryngeal resistance (cmH2O/l/s) and standard deviation of laryngeal resistance (cmH2O/l/s). Results indicated that the masked auditory feedback condition significantly increased variability in performance across all 3 voice qualities and specifically, the masked auditory feedback condition facilitated significantly higher mean laryngeal resistance values for the pressed voice quality but not for the breathy and the normal voice qualities. As a potential explanation of the current findings in Experiment 1, it is hypothesized that the bimanual coordination task did not rely on visual and auditory feedback because the task was governed by proprioceptive feedback, which was not controlled in the present study. For Experiment 2, sensory feedback may be relevant for voice patterns that have a shallow basin of attraction (i.e., pressed voice), but irrelevant for voice patterns that have a steep basin of attraction (i.e., breathy and normal voice). Perhaps the breathy and normal voice qualities were governed by voice coordination dynamics, while the pressed voice quality was partly influenced by auditory feedback connections. In addition, level of expertise may also play a role in the coordination dynamics of a voice task. The influence of auditory feedback on voice coordination dynamics suggests an expanded view of dynamic systems theory and supports the role of auditory feedback in vocal rehabilitation.

The kinetics of the rate-limiting genes of the molecular DNA repair pathways of nucleotide excision repair (NER) were quantified from the inner ear as a function of cis-diamminedichloroplatinum-II (cisplatin) treatment. The distribution of the post-translational products of these genes was evaluated among neurons and sensory hair cells of the inner ear following cisplatin treatment. These NER factors (genes & post-translational products) are only potentiated by DNA damage and are particularly sensitive to cisplatin induced DNA damage. A 2 x 3 x 2 factorial design, consisting of two treatment conditions (saline and cisplatin treated Fischer344 rats), three survival times and two molecular analysis methods (polymerase chain reaction and immunohistochemistry) was employed in this dissertation. The results revealed at least five important findings. First, it revealed for the first time that complex DNA repair molecular pathways such as NER exist in the inner ear. Second, it revealed for the first time that molecules used by advanced tumor cells to detect and repair damaged DNA from cisplatin genotoxicity also generalize to the inner ear and are stimulated by even small sub-toxic doses of cisplatin. Third, it revealed for the first time that NER proteins reside in the cytoplasm of neurons under normal conditions and translocate to the nucleus under conditions of genomic stress. Fourth, it revealed for the first time that the basal coil of the mammalian cochlea differs from the apical coil in the magnitude and latency in which NER molecules translocate from the cytoplasm to the nucleus under conditions of genomic stress. Fifth, the current work provides the bases for a new line of hearing research focused on molecular mechanisms of inner ear DNA repair.

The purpose of this study was to determine the point at which a minimally complex well-trained nonspeech task transfers to other nonspeech tasks of varying complexity. Participants included ten normal adult speakers. The nonspeech training task included bilabial production of a single intraoral pressure peak at either 7 or 15 cm H2O. Participants received random training on the two pressure targets, with Knowledge of Results provided on 50% of the trials. Complexity of the transfer tasks was manipulated by varying both the number of intraoral pressure peaks and the consistency of pressure targets. Only 4 participants demonstrated learning of the single peak task. For these four participants, transfer occurred from the training task to the more complex transfer tasks at roughly the same time. Findings suggest that there was no difference in complexity between number of pressure peaks and the consistency of the pressure targets.