Biomedical subjects

Christopher Dromey

Publications and source records attributed to Christopher Dromey.

4 recordsLinked to original sources

PubMed2005

Speech interactions with linguistic, cognitive, and visuomotor tasks.

Lip movements were examined across several repetitive speaking conditions (speech alone and speaking concurrently with a linguistic, cognitive, or visuomotor challenge task) in 20 young adults. Performance in these nonspeech activities was also compared between isolated tasks and concurrent speech conditions. Linguistic challenges resulted in increased spatiotemporal variability of lip displacement across repetitions. Motor challenges led to more rapid speech with smaller lip displacement. These qualitatively different changes suggest that different aspects of attention are required for linguistic versus manual visuomotor activity. Vocal intensity increased for all concurrent task conditions compared with speech alone, suggesting increased effort compared to the control condition. Scores for linguistic performance decreased when utterance repetition occurred concurrently with the syntactic challenge. These findings reveal that speech motor activity can influence linguistic performance as well as be influenced by it. Although these data come from healthy speakers, they suggest that clinicians working with disordered speakers should not overlook the potential interactions among the demands of language formulation, cognitive activity, and speech motor performance.

Adult↗

PubMed2003

Vibrato rate adjustment.

The goal of the present study was to document the acoustic changes that occur as singers attempt to increase or decrease their vibrato rate to match target stimuli. Eight advanced singing students produced vowels with vibrato in three registers, both naturally and while attempting to match faster or slower rate stimuli. Slower rates were associated with lower intensity and less steady vibrato. Faster rates involved increased vibrato extent in the chest register and increased intensity in the head register. Singers whose spontaneous vibrato rates were naturally either slower or faster tended to also be relatively slower or faster when matching target rates. This ability to modify rate may have beneficial effects on the artistic quality of the voice for performance.

Glottis↗

PubMed2003

Effects of concurrent motor, linguistic, or cognitive tasks on speech motor performance.

This study examined the influence of 3 different types of concurrent tasks on speech motor performance. The goal was to uncover potential differences in speech movements relating to the nature of the secondary task. Twenty young adults repeated sentences either with or without simultaneous distractor activities. These distractions included a motor task (putting together washers, nuts, and bolts), a linguistic task (generating verbs from nouns), and a cognitive task (performing mental arithmetic). Lip movement data collected during the experimental conditions revealed decreases in displacement and velocity during the motor task. The linguistic and cognitive tasks were associated with increased spatiotemporal variability and increases in the strength of the negative correlations between upper and lower lip displacements. These findings show that distractor tasks during speech can have a significant influence on several labial kinematic measures. This suggests that the balance of neural resources allocated to different aspects of human communication may shift according to situational demands.

Adult↗

PubMed2002

The influence of pitch and loudness changes on the acoustics of vocal tremor.

The effect of tremor on phonation is to modulate an otherwise steady sound source in its amplitude, fundamental frequency, or both. The severity of untreated vocal tremor has been reported to change under certain conditions that may be related to muscle tension. In order to better understand the phenomenon of vocal tremor, its acoustic properties were examined as individuals volitionally altered their pitch and loudness. These voice conditions were anticipated to alter the tension of the intrinsic laryngeal muscles. The voices of 10 individuals with a diagnosis of vocal tremor were recorded before participating in a longitudinal treatment study. They produced vowels at low and high pitch and loudness levels as well as in a comfortable voice condition. Acoustic analyses quantified the amplitude and frequency modulations of the speakers' voices across the various conditions. Individual speakers varied in the way the pitch and loudness changes affected their tremor, but the following statistically significant effects for the speakers as a group were observed: Higher pitch phonation was associated with a more rapid rate for both amplitude and frequency modulations. Amplitude modulation become faster for louder phonation. Low-pitched phonotion led to decreases in the extent of amplitude tremor. Varying pitch led to dramatic changes in the phase relationship between amplitude and frequency modulation in some of the speakers, whereas this effect was not apparent in other speakers.

Aged↗