The effect of simulated radiation induced fibrosis on tongue protrusion.

Radiation therapy (RT) is an important adjuvant and primary treatment modality for head and neck cancers. A severe side effect of RT is fibrosis or scarring of muscle tissues of the oral cavity including the tongue. Previous studies have demonstrated that increased radiation doses to the oral cavity structures have led to decrements in function, hypothesized to result from changes in muscle tissue properties that affect the tongue's function. To understand the complex relationship between tongue muscle fibrosis and tongue function, the current study used a virtual biomechanical model of the tongue. Fibrosis parameters including density (high, low), area (large, small) and location (946 node centres) were systematically varied in the model to test its impact on a target tongue tip motion (protrusion). The impact of fibrosis lesion parameters on three directional components of the tip (anterior-inferior, lateral-medial, and superior-inferior) were analyzed using multi linear regression models. Increases in density and area of fibrosis significantly predicted tongue protrusion movements compared to baseline. In the anterior-posterior direction, reductions in the tongue protrusion were observed. In the inferior-superior direction, the tongue height remained above baseline for the majority of cases. In the lateral-medial direction, ipsilateral deviations were observed. The location of fibrosis modulated these three main effects by either amplifying the observed effect or minimizing it. The findings support the hypothesis that changes in muscle tissue properties because of fibrosis impact tongue function. Increases in density and area of fibrosis impact key muscles in the target motion. The range of modulating effects of the lesion location (i.e., either amplifying or minimizing certain impact patterns) highlights the intricacy of tongue anatomy/soft tissue biomechanics and may suggest that lesions in any location will compromise the tongue's movement.

The Effects of Contextual Priming and Alaryngeal Speech Mode on Auditory-Perceptual Ratings of Listener Comfort.

BACKGROUND: The effectiveness of postlaryngectomy communication methods (esophageal, tracheoesophageal, and electrolaryngeal speech) has been primarily evaluated using functional outcomes. This evaluation neglects the importance of listeners and their influence on communicative effectiveness. Listener comfort (LC), or the ease with which a listener interacts with alaryngeal speakers, may provide an important index of communicative effectiveness. The present study investigated the use of LC in the auditory-perceptual evaluation of alaryngeal speech modes, as well as evaluating the influence of contextual cues used to elicit ratings on listener judgments of all three alaryngeal modes. METHODS: Thirty-three naïve listeners provided independent ratings of LC for 39 alaryngeal speech samples using a visual analogue scaling procedure. Each group of listeners rated alaryngeal speech in three imagined listening conditions (Telephone Conversation, Social Situation, and a non-specified Control Condition). To analyze LC ratings obtained, a 3 × 3 mixed factor analysis of variance was conducted. RESULTS: A significant interaction effect between alaryngeal speech mode and listening condition (P = 0.04) was identified. Overall, pairwise comparisons of alaryngeal speech mode indicated that listeners were more comfortable when presented with tracheoesophageal speech samples compared to those of esophageal and electrolaryn geal speakers. CONCLUSIONS: Our data suggest that LC ratings are influenced by alaryngeal speech mode. Tracheoesophagea speech was perceived to have the most favorable LC ratings compared to the other alaryngeal speech modes in all listening conditions. Contextual cues (i.e., social condition and telephone condition) did not have an effect on LC ratings.

Using visual feedback to enhance intonation control with a variable pitch electrolarynx.

This study evaluated the effectiveness of using visual feedback to facilitate pitch control by a speaker using a pressure sensitive onset controlled electrolarynx (EL). This proof-of-concept study was conducted with one healthy adult. The participant-speaker was provided with computer generated visual feedback over five sessions within a consecutive period of three weeks. Changes in force control accuracy were gathered and analyzed. An improvement in finger (thumb) force control accuracy from the first to the last training session was documented. The results of this study provide data toward the development of a clinical training protocol for the use of a pressure sensitive onset controlled EL by laryngectomized speakers. Further, these results highlight the importance of developing a relevant multimodality training protocol for the improvement of postlaryngectomy EL speech production.

Evidence for a global oculomotor program in reading.

Recent corpus studies of eye-movements in reading revealed a substantial increase in saccade amplitudes and fixation durations as the eyes move over the first words of a sentence. This start-up effect suggests a global oculomotor program, which operates on the level of an entire line, in addition to the well-established local programs operating within the visual span. The present study investigates the nature of this global program experimentally and examines whether the start-up effect is predicated on generic visual or specific linguistic characteristics and whether it is mainly reflected in saccade amplitudes, fixation durations or both measures. Eye movements were recorded while 38 participants read (a) normal sentences, (b) sequences of randomly shuffled words and (c) sequences of z-strings. The stimuli were, therefore, similar in their visual features, but varied in the amount of syntactic and lexical information. Further, the stimuli were composed of words or strings that either varied naturally in length (Nonequal condition) or were all restricted to a specific length within a sentence (Equal). The latter condition constrained the variability of saccades and served to dissociate effects of word position in line on saccade amplitudes and fixation durations. A robust start-up effect emerged in saccade amplitudes in all Nonequal stimuli, and-in an attenuated form-in Equal sentences. A start-up effect in single fixation durations was observed in Nonequal and Equal normal sentences, but not in z-strings. These findings support the notion of a global oculomotor program in reading particularly for the spatial characteristics of motor planning, which rely on visual rather than linguistic information.