Alexander M. Goberman

Phonatory characteristics of Parkinsonian speech before and after morning medication: the ON and OFF states

UNLABELLED After prolonged treatment with L-dopa, patients with Parkinsons disease (PD) experience fluctuations in motor performance. Changes in voice production have been documented perceptually during periods of fluctuation, but few quantitative changes have been found. The purpose of this study is to examine the acoustic-phonatory characteristics of PD speech before and after taking medication, to determine if fluctuations affected phonation. Nine PD patients participated in this study. Multiple analyses were performed, and revealed that fundamental frequency (Fo) variability in vowels and mean Fo were higher, while intensity range was lower in PD patients compared to controls. When the PD subjects were examined after versus before medication, group differences were small, but phonatory improvements were seen in individual subjects. Discussion focuses on physiological changes and variability in PD, and implications of response fluctuations to speech production. LEARNING OUTCOMES As a result of this activity, the participant will be able to (1) acquire knowledge and understanding of PD and the voice characteristics commonly associated with PD and (2) understand the effects of L-dopa-related fluctuations on voice production in PD.

Parkinsonian speech disfluencies: effects of L-dopa-related fluctuations

UNLABELLED The excess dopamine theory of stuttering (Wu et al., 1997) contends that stuttering may be related to excess levels of the neurotransmitter dopamine in the brain. As Parkinsons disease (PD) patients commonly exhibit changes in dopamine levels accompanied by changes in motor performance, the present study examined disfluency in PD patients to gain information on the role of dopamine in speech disfluencies. Nine PD patients with no history of developmental stuttering were recorded once before and twice after taking their morning medication (on separate days). They read a passage and produced a monologue. Within-word and overall speech disfluencies were calculated at each recording. Through motor testing, it was inferred that participants had relatively low dopamine levels before taking medication, and relatively high dopamine levels after taking medication. There were no group changes in disfluency levels when the low-dopamine and high-dopamine states were compared. There were, however, significant differences in percent disfluencies between the PD participants and age-matched controls. The results of this study do not strongly support the excess dopamine theory of stuttering. Rather, the disfluency changes exhibited by individual participants support a hypothesis that speech disfluencies may be related to increases or decreases in dopamine levels in the brain. EDUCATIONAL OBJECTIVES The reader will learn about: (1). the characteristics of disfluent speech exhibited by speakers with Parkinsons disease. (2). The effect of L-dopa based medications on disfluencies of Parkinsonian speakers. (3). The complex role brain dopamine levels may play in disfluent speaking behavior.

Voice onset time in Parkinson disease

UNLABELLED Research has found that speaking rate has an effect on voice onset time (VOT). Given that Parkinson disease (PD) affects speaking rate, the purpose of this study was to examine VOT with the effect of rate removed (VOT ratio), along with the traditional VOT measure, in individuals with PD. VOT and VOT ratio were examined in 9 individuals with PD (before and after taking medication), along with 9 matched controls. Place of articulation and vowel height had significant effects on VOT and VOT ratio for all groups, and there were no PD versus control differences. PD medication had a greater effect on VOT than VOT ratio, reflecting a rate-related VOT change rather than a pure VOT change. These data support the usefulness of examining both VOT and VOT ratio with individuals with PD, as this allows for dissociation between rate-related VOT changes and true VOT changes. LEARNING OUTCOMES The reader will be able to understand and describe: (1) voice onset time (VOT) and VOT ratio; (2) how VOT and VOT ratio are affected in individuals with Parkinson disease; and (3) the effect of medication on VOT and VOT ratio.

Characteristics of speech disfluency in Parkinson disease

The purpose of this study was to describe speech disfluency characteristics in a group of 32 individuals with Parkinson disease (PD). Individuals with PD read a standard passage, and percentages of within-word and between-word disfluencies were calculated. The disfluency percentages exhibited by the individuals with PD were significantly greater than age-matched control speakers. Similarity was found between PD-related disfluencies and disfluencies seen in developmental stuttering, as the PD participants produced primarily motoric-based within-word disfluencies, including both repeated movements and fixed postures. A relationship was also found between self-ratings of medication effectiveness and disfluency levels, and this relationship is interpreted relative to the dopamine hypothesis of stuttering. Finally, significant reductions in within-word disfluencies were seen during a clear-speech task, along with an increase in disfluency levels during a monologue compared to a reading task.

Articulatory-acoustic vowel space: application to clear speech in individuals with Parkinson's disease.

BACKGROUND/PURPOSE Individuals with Parkinson disease (PD) often exhibit decreased range of movement secondary to the disease process, which has been shown to affect articulatory movements. A number of investigations have failed to find statistically significant differences between control and disordered groups, and between speaking conditions, using traditional vowel space area measures. The purpose of the current investigation was to evaluate both between-group (PD versus control) and within-group (habitual versus clear) differences in articulatory function using a novel vowel space measure, the articulatory-acoustic vowel space (AAVS). METHODS The novel AAVS is calculated from continuously sampled formant trajectories of connected speech. In the current study, habitual and clear speech samples from twelve individuals with PD along with habitual control speech samples from ten neurologically healthy adults were collected and acoustically analyzed. In addition, a group of listeners completed perceptual rating of speech clarity for all samples. RESULTS Individuals with PD were perceived to exhibit decreased speech clarity compared to controls. Similarly, the novel AAVS measure was significantly lower in individuals with PD. In addition, the AAVS measure significantly tracked changes between the habitual and clear conditions that were confirmed by perceptual ratings. CONCLUSIONS In the current study, the novel AAVS measure is shown to be sensitive to disease-related group differences and within-person changes in articulatory function of individuals with PD. Additionally, these data confirm that individuals with PD can modulate the speech motor system to increase articulatory range of motion and speech clarity when given a simple prompt. LEARNING OUTCOMES The reader will be able to (i) describe articulatory behavior observed in the speech of individuals with Parkinson disease; (ii) describe traditional measures of vowel space area and how they relate to articulation; (iii) describe a novel measure of vowel space, the articulatory-acoustic vowel space and its relationship to articulation and the perception of speech clarity.

Acoustic characteristics of public speaking: Anxiety and practice effects

This study describes the relationship between acoustic characteristics, self-ratings, and listener-ratings of public speaking. The specific purpose of this study was to examine the effects of anxiety and practice on speech and voice during public speaking. Further examination of the data was completed to examine the illusion of transparency, which hypothesizes that public speakers think their anxiety is more noticeable to listeners than it really is. Self-rating and acoustic speech data were reported on two separate speeches produced by 16 college-aged individuals completing coursework in interpersonal communication. Results indicated that there were significant relationships between acoustic characteristics of speech and both self- and listener-ratings of anxiety in public speaking. However, self-ratings of anxiety were higher than listener ratings, indicating possible confirmation of the illusion of transparency. Finally, data indicate that practice patterns have a significant effect on the fluency characteristics of public speaking performance, as speakers who started practicing earlier were less disfluent than those who started later. Data are also discussed relative to rehabilitation for individuals with communication disorders that can be associated with public speaking anxiety.

The effects of changes in speaking rate on nasal airflow and the perception of nasality.

The effects of variation in speaking rate on relative nasal airflow (percent nasal flow) and on the perception of nasality were examined. In addition, the effects of gender and speech rate elicitation techniques (metronome-controlled, self-controlled) were examined. Nineteen normal speakers each produced a stimulus phrase containing nonnasal sounds. Oral and nasal airflows were measured using the Rothenberg aerodynamic system. Results indicated that percent nasal flow and perception of nasality were both greater at slow speaking rates compared to normal and fast rates. Males were perceived as more nasal than females. The metronome-controlled rates were associated with greater nasality than the self-controlled rates. Discussion focuses on physiological correlates to these findings.

Acoustic characteristics of crying in infantile laryngomalacia

The purpose of this study was to add to the extant data base of acoustic cry studies by profiling the condition of laryngomalacia. We hypothesized that the acoustic characteristics of crying produced by an infant with laryngomalacia would differ compared to previously reported cry data for normal infants. An entire episode of crying was audio recorded and acoustically analyzed for the occurrence of expiratory and inspiratory cry segments, as well as the long-time average spectral (LTAS) characteristics. Results obtained for the infant were found to be considerably different from what has been previously reported for normal infants. The overall duration of the infants crying episode was longer, with proportionately fewer expiratory phonations and more inspiratory phonations compared to normal infants. The LTAS results were reflective of aperiodic components in the glottal source spectrum. Collectively, the infants unusual crying aspects were not limited solely to those acoustic features resulting from a prolapse of supraglottic soft tissue, and therefore provide new insight into the vocal fold vibratory behavior characterizing infantile laryngomalacia.

Speech Motor Sequence Learning: Acquisition and Retention in Parkinson Disease and Normal Aging

Purpose The aim of the current investigation was to examine speech motor sequence learning in neurologically healthy younger adults, neurologically healthy older adults, and individuals with Parkinson disease (PD) over a 2-day period. Method A sequential nonword repetition task was used to examine learning over 2 days. Participants practiced a sequence of 6 monosyllabic nonwords that was retested following nighttime sleep. The speed and accuracy of the nonword sequence were measured, and learning was inferred by examining performance within and between sessions. Results Though all groups exhibited comparable improvements of the nonword sequence performance during the initial session, between-session retention of the nonword sequence differed between groups. Younger adult controls exhibited offline gains, characterized by an increase in the speed and accuracy of nonword sequence performance across sessions, whereas older adults exhibited stable between-session performance. Individuals with PD exhibited offline losses, marked by an increase in sequence duration between sessions. Conclusions The current results demonstrate that both PD and normal aging affect retention of speech motor learning. Furthermore, these data suggest that basal ganglia dysfunction associated with PD may affect the later stages of speech motor learning. Findings from the current investigation are discussed in relation to studies examining consolidation of nonspeech motor learning.

Long-time average spectrum in individuals with Parkinson disease

BACKGROUND Various methods of acoustic analysis have been used to describe phonatory deficits in Parkinson disease (PD), including long-time average spectrum (LTAS) analysis. OBJECTIVE The aim of this study was to utilize the LTAS to investigate laryngeal deficits in individuals with PD. METHODS Twenty-eight individuals with idiopathic PD and 10 controls were participants for this study. An LTAS was generated from a standard reading sample and analyzed using the following measurements: Mean spectral energy (MSE), first spectral peak, spectral tilt (ST), three spectral slope (SS) measures (i.e., SSF0-1kHz, SS1-5kHz, and SS ratio) and four spectral moments (mean, standard deviation, skewness, and kurtosis). RESULTS Individuals with PD were found to demonstrate significantly lower MSE, spectral mean and spectral SD, along with higher spectral skewness compared to control speakers. Furthermore, ST was positively correlated with self-rated symptom severity and self-rated medication effectiveness for individuals with PD. CONCLUSIONS The LTAS findings were consistent with either reduced vocal fold adduction or vocal fold bowing in individuals with PD compared to control speakers. Additionally, vocal fold adductory changes were one possible explanation for correlations between LTAS and self-ratings of medication effectiveness and disease severity.