Biomedical subjects

B E Guitar

Publications and source records attributed to B E Guitar.

5 recordsLinked to original sources

PubMed1983

Control of upper airway structures during nonspeech tasks in normal and cerebral-palsied subjects: EMG findings.

Electromyographic (EMG) recordings taken from 13 orofacial and mandibular muscles during a sequence of nonspeech movements were compared in six normal and six cerebral-palsied adult subjects. Abnormalities in the amplitude of muscle activity and timing of muscle control in the cerebral-palsied subjects were borne out in statistically significant differences between the two subject groups on five measures of muscle activity. The findings do not support hypotheses that weakness affects individual upper airway muscles in cerebral-palsied persons or that a pathological imbalance between positive and negative oral reactions is present in these subjects. A possible mechanism for hypertonicity in facial muscles in cerebral palsy is suggested, based on inappropriate activation patterns across muscles. The results are consistent with a previous proposal that a defect in the specification of motor commands and/or their communication to muscles is a fundamental abnormality in cerebral-palsied individuals which affects both speech and nonspeech motor control.

Adult↗

PubMed1982

Stuttering: speech pattern characteristics under fluency-inducing conditions.

Speech samples were collected from three adult male stutterers under six baseline conditions and 15 conditions believed to increase fluency. After moments of stuttering and filled pauses had been deleted from the samples, a speech pause analysis technique developed by Goldman-Eisler was used to measure the following speech pattern characteristics: mean phonation duration (i.e., the duration between pauses), pause proportion, articulation rate, fluent speech rate, mean sentence length, and percentage of syllables stuttered. Greater than 50% reduction in stuttering occurred in all but three conditions (Speak and Write, Relaxed, Alone with cards). Greater than 90% reduction occurred under Prolonged/DAF speech, Singing, Chorus reading, Shadowing, Slowing, Syllable-timed speech, and Response contingent stimulation. The data were examined for evidence of speech pattern characteristic changes which were associated with reduced stuttering. Lengthened mean phonation duration occurred consistently under four conditions: Chorus reading, Shadowing, Singing, and Prolonged/DAF. Slowed speech (lower overall rate, lower articulation rate, or increased pause proportion) occurred consistently in seven conditions: Prolonged/DAF, Slowing, Syllable-timed speech, Arm swing, Speak and write, Relaxed, and Singing. Only in Prolonged/DAF speech did lengthened phonation duration occur in conjunction with slowed speech. The results of this exploratory study suggest that stuttering may be reduced under different conditions by means of different strategies. Lengthened phonation and slowing were the predominant strategies used in those conditions investigated in this study. The results are consistent with those of effective treatment techniques. Theoretical accounts of the association between change in fluency and change speech pattern characteristics are discussed.

Humans↗

PubMed1981

Procedures for verification of electrode placement in EMG studies of orofacial and mandibular muscles.

Many muscles used in speech are small and intimately interconnected. There is a need for anatomical and physiological data which would allow identification of the particular muscle fibers being recorded in electromyographic (EMG) investigations. EMG recordings were taken from eighteen orofacial and mandibular muscles while gestures believed to be specific to each muscle were performed. The anatomic criteria for the placement of the electrodes, the quality of the EMG spikes and interference patterns obtained, and the degree of differentiation of the temporal sequence of activity from that in neighboring muscles were used to decide on the degree of certainty that a particular muscle was being recorded. The appropriateness of each gesture as a stimulus to any muscle was determined on the basis of the level of activation occurring with the gesture relative to other muscles and its degree of variability between subjects.

Electrodes↗

PubMed1979

Tonic stretch reflexes in lip, tongue and jaw muscles.

Despite considerable speculation it remains unclear as to whether stretch reflexes perform a functional role in speech articulator muscles. Recent research, however, has shown that long loop stretch reflex mechanisms are brought into play during voluntary contraction of limb muscles and a functional role in oscillatory damping has been suggested. It was decided, therefore, to use a method and a technique of analysis similar to that used in limb muscles to search for tonic stretch reflex (TSR) responses in lip, tongue and jaw muscles during sustained voluntary contraction. The term 'action TSR' is used to differentiate stretch reflex responses measured from voluntary activity from those measured at rest. Simultaneous electromyogram (EMG) recordings were taken from the lip, tongue and jaw musculature in normal, stutterer and cerebral spastic subjects. Subjects were instructed to hold the appropriate articulator in a fixed position while the experiment applied an irregular, continuously changing, stretching force. The stretch and EMG signals were analyzed using a cross correlation and spectral analysis technique. This provided a sensitive means of detecting any EMG fluctuations which covaried with applied stretch and might therefore be classified as reflex. No suggestion of such action TSR responses could be found in lip or tongue muscles of any of the subjects tested, including the cerebral spastic subjects with dysarthric speech. It is therefore concluded that action TSR mechanisms are not operative in control of lip and tongue muscles in man. Furthermore, dysarthric speech in cerebral spasticity cannot be attributed to exaggerated tone of lip and tongue muscles resulting from hypersensitivity of TSR mechanisms. In contrast, clear action TSR responses were demonstrable in jaw closing muscles while in jaw opening muscles, small amplitude responses were detected but were not substantial in comparison with background activity. Since the action TSR is present in jaw and limb muscles, but absent in lip and tongue muscles, the suggestion of a functional role of this reflex in damping mechanical oscillations associated with inertial loads is further supported.

Adult↗

PubMed1979

Speech clinicians' attribution of personality traits as a function of stuttering severity.

Thirty-six speech-language pathologists participated in a study to evaluate clinicians' preconceptions of persons who stutter. Each rated a designated construct (the normally fluent individual, the mild stutterer, the moderate stutterer, the severe stutterer) using a personality trait scale. Results indicated that clinicians stereotypically assign negative personality traits to all levels of stuttering severity relative to normal. Their ratings further demonstrated that stutterers are generally considered to be a homogenous group. Differentiation amongst stutterers was made only between the polar ends of the stuttering severity continuum (that is, mild vs. severe). Clinicians' sterotypical trait assignment was not related to their professional experience. Results are discussed with reference to their clinical implications.

Humans↗