Faculty Bibliography

A 36-year-old female with severe spastic dysarthria participated in this study. She received 4 weeks of individual intensive voice-focused treatment. Voice recordings were conducted at three baseline points, immediately posttreatment, and at a 4-month follow-up. The primary outcome variables were selected acoustic measures of vocal function: sound pressure level (SPL), mean fundamental frequency (F0), maximum phonation time (MPT), jitter, shimmer, noise-to-harmonics ratio (NHR), and maximum phonation frequency range (MPFR). Significant pre-to-posttreatment changes (p <.05) were found for most acoustic variables. All acoustic gains, except for MPFR, were maintained at the 4-month follow-up. The significant posttreatment changes in the majority of the acoustic measures analyzed suggest that intensive voice-focused treatment may have the potential to improve vocal function in adults with severe spastic dysarthria secondary to cerebral palsy (CP). Evidence-based treatment options for voice disorders in adults with CP are limited. Results emphasize the need for more studies with this population.

Previous studies in animals and humans suggest the periaqueductal grey region (PAG) is a final integration station between the brain and laryngeal musculature during phonation. To date, a limited number of functional magnetic neuroimaging (fMRI) studies have examined the functional connectivity of the PAG during volitional human phonation. An event-related, stimulus-induced, volitional movement paradigm was used to examine neural activity during sustained vocalization in neurologically healthy adults and was compared to controlled exhalation through the nose. The contrast of vocalization greater than controlled expiration revealed activation of bilateral auditory cortex, dorsal and ventral laryngeal motor areas (dLMA and vLMA) (p<0.05, corrected), and suggested activation of the cerbellum, insula, dorsomedial prefrontal cortex (dmPFC), amygdala, and PAG. The functionally defined PAG cluster was used as a seed region for psychophysiological interaction analysis (PPI) to identify regions with greater functional connectivity with PAG during volitional vocalization, while the above functionally defined amygdala cluster was used in an ROI PPI analysis. Whole-brain results revealed increased functional connectivity of the PAG with left vLMA during voicing, relative to controlled expiration, while trend-level evidence was observed for increased PAG/amygdala coupling during voicing (p=0.07, uncorrected). Diffusion tensor imaging (DTI) analysis confirmed structural connectivity between PAG and vLMA. The present study sheds further light on neural mechanisms of volitional vocalization that include multiple inputs from both limbic and motor structures to PAG. Future studies should include investigation of how these neural mechanisms are affected in individuals with voice disorders during volitional vocalization.

PURPOSES: To test the hypothesis that extensive use of La MaMa vocal technique may result in symptoms of vocal abuse, an evaluation of the acoustic and perceptual characteristics of voice for eight performers from the Great Jones Repertory Company of the La MaMa Experimental Theater was conducted. This vocal technique includes wide ranges of frequency from 46 to 2003 Hz and vocal intensity that is sustained at 90-108 dB sound pressure level with a mouth-to-microphone distance of 30 cm for 3-4 hours per performance. METHODS: The actors rehearsed for 4 hours per day, 5 days per week for 14 weeks before the series of performances. Thirty-nine performances were presented in 6 weeks. Three pretraining, three posttraining, and two postperformance series data collection sessions were carried out for each performer. Speech samples were gathered using the CSL 4500 and analyzed using Real-Time Pitch program and Multidimensional Voice Program. Acoustic analysis was performed on 48 tokens of sustained vowel phonation for each subject. Statistical analysis was performed using the Friedman test of related samples. Perceptual analysis included professional listeners rating voice quality in pretraining, posttraining, and postperformance samples of the Rainbow Passage and sample lines from the plays. RESULTS: The majority of professional listeners (11/12) judged that this technique would result in symptoms of vocal abuse; however, acoustic data revealed statistically stable or improved measurements for all subjects in most dependent acoustic variables when compared with both posttraining and postperformance trials. CONCLUSION: These findings add support to the notion that a technique that may be perceived as vocally abusive, generating 90-100 dB sound pressure level and sustained over 6 weeks of performances, actually resulted in improved vocal strength and flexibility.

The objectives of this study are to describe central nervous system modulation associated with voice improvement following Type I thyroplasty in a patient with glottic insufficiency secondary to unilateral vocal fold paralysis. Serial functional magnetic resonance imaging scans were performed before as well as one and six months after thyroplasty. Paradigms consisting of four voice production tasks and a motor control task were completed. Volumes of activation within regions activated during each task were measured. Acoustic and aerodynamic measures were also obtained. A widespread network of neural activations was shown for all tasks. Differences in volumes of activation 1-month postsurgery positively correlated with acoustic and aerodynamic improvements. Sixth months following medialization, lesser volumes of activation were observed in all regions. Prior to this session, however, the patient's mediastinal disease progressed, leading to a significant deterioration in voice. Functional differences between patient brain maps yield new information about the central nervous system's ability to reorganize sensorimotor representations associated with voice improvement following Type I thyroplasty in a patient with glottic insufficiency secondary to unilateral vocal fold paralysis (UVFP)

Voice production involves precise, coordinated movements of the intrinsic and extrinsic laryngeal musculature. A component of normal voice production is the modification of pitch. The underlying neural networks associated with these complex processes remains poorly characterized. However, several investigators are currently utilizing neuroimaging techniques to more clearly delineate these networks associated with phonation. The current study sought to identify the central cortical mechanism(s) associated with pitch variation during voice production using event-related functional MRI (fMRI). A single-trial design was employed consisting of three voice production tasks (low, comfortable, and high pitch) to contrast brain activity during the generation of varying frequencies. For whole brain analysis, volumes of activation within regions activated during each task were measured. Bilateral activations were shown in the cerebellum, superior temporal gyrus, insula, precentral gyrus, postcentral gyrus, inferior parietal lobe, and post-cingulate gyrus. In the left hemisphere, activations in the medial and middle frontal gyri were also observed. Regions active during high pitch production when compared to comfortable pitch were evident in the bilateral cerebellum, left inferior frontal gyrus, left cingulate gyrus, and left posterior cingulate. During low pitch generation, activations were present in the inferior frontal gyrus, insula, putamen, and cingulate gyrus in the left hemisphere. The inferior frontal gyrus in the right hemisphere produced greater activity than the area of the left hemisphere during high and low pitch generation. These results suggest that a single-trial design is sensitive enough to begin to delineate a widespread network of activations in both hemispheres associated with vocal pitch variation

The Bereitschaftspotential (BP) is a slow negative-going cortical potential associated with preparation for volitional movement. Studies since the 1960s have provided evidence for a BP preceding speech-related volitional motor acts. However, the BP associated specifically with phonation [corrected] has not to date been systematically investigated. The current investigation utilizes a novel experimental design to address methodological confounds typically found in studies of movement-related cortical potentials, to demonstrate the existence and localization of generators for the voice-related cortical potential (VRCP). Using high-density EEG, we recorded scalp potentials in preparation for voicing and controlled [corrected] exhalation in a stimulus-induced voluntary movement task. Results showed a slow, increasingly negative cortical potential in the time window of of a standard BP prior [corrected] to the mean onset of phonation. This VRCP peaked at a greater amplitude and shorter latency than the BP associated with exhalation alone. Region analysis exhibited a steeper slope of the late VRCP in the primary motor area (M1) than that in the Supplementary [corrected] Motor Area (SMA), reflecting the complexity of motor movements and control necessary for voicing. Additionally, the late VRCP offset in M1 (-400 ms) was later than that in the SMA (-600 ms), possibly reflecting later engagement of primary motor areas following motor preparation in premotor areas [corrected] Further examination of the spatiotemporal change of the VRCP yielded source models indicating [corrected] involvement of the cortical regions [corrected] responsible for the initiation and continuation of phonation. Sources were localized to the middle frontal gyri and M1, bilaterally. Additional sources were localized to bilateral cerebellum and occipital lobe [corrected]