Lingual Vibrotactile Thresholds Research Articles

Effects of stimulus duration and stimulus intensity level on recovery times for lingual vibrotactile threshold shift

The time required for lingual vibrotactile thresholds of normal young adults to return to baseline levels of sensitivity was determined following presentations of a 250-Hz stimulus for durations of 5 and 15 sec at eight different intensity levels. Results indicated that stimulus duration and stimulus intensity levels significantly affected threshold recovery time. Longer recovery times were noted for stimuli of greater duration and intensity.

Differences in lingual vibrotactile threshold shifts during magnitude-estimation scaling between normal-speaking children and children with articulation problems.

The purpose of this study was to investigate differences in function of the tactile sensory system between groups of normal-speaking children and children with articulation problems. This task was accomplished by studying possible tactile threshold shifts occurring during magnitude-estimation scaling of vibratory stimuli presented to the dorsal surface of the tongue. 10 normal-speaking children (M age = 7.8 yr.) and 9 children with articulation problems (M age = 7.5 yr.) participated. The normal-speaking children and articulatory defective children performed differently on the magnitude-estimation scaling task in which threshold was allowed to return to baseline after each stimulus presentation. These two groups of children also showed dissimilar threshold shifts for the suprathreshold intensities employed in the magnitude-estimation scaling.

Lingual vibrotactile threshold and suprathreshold responses of normal-speaking black and white young adults.

A paradigm for studying oral sensory tactile function through use of single frequency vibration applied to the dorsal surface of the tongue was administered to a group of 10 young black women and 10 young white normal-speaking women. Analyses showed no differences between groups with regard to lingual vibrotactile threshold of sensitivity or suprathreshold magnitude-estimation scaling responses.

Effects of Auditory Disruption of Lingual Tactile Sensitivity in Skilled and Unskilled Speaking Conditions

The purpose of this study was to investigate the effect of disruption of the auditory feedback channel on lingual vibrotactile thresholds obtained under skilled and unskilled speaking conditions. Each of 22 adults was asked to read an English (skilled) and French (unskilled) passage under conditions of normal and altered auditory feedback. Bilateral presentation of masking noise was utilized to disrupt auditory feedback. Before each of the experimental sessions and immediately following a reading, lingual vibrotactile thresholds were obtained. Analysis indicated that the mean differences in the pre- and postvibrotactile threshold measurements of the skilled auditory disrupted condition varied significantly from the mean differences in the pre- and postvibrotactile threshold measurements of the three other conditions. The role of feedback in the speech production of skilled and unskilled speakers is discussed.

Lingual Vibrotactile Threshold Shift Differences between Stutterers and Normal Speakers during Magnitude-Estimation Scaling

The purpose of this study was to investigate differences in tactile sensory system function between stutterers and normal speakers. This task was accomplished by studying possible tactile threshold shifts occurring during magnitude-estimation scaling of vibratory stimuli presented to the dorsal surface of the tongue. Ten normal speaking men (M age = 19.7 yr.) and 10 stutterers (M age = 25.9 yr.) participated. Analysis suggested that stutterers and normal speakers differ in terms of the responsiveness of the sensory mechanism for the lingual tactile threshold to vibratory stimulus intensities applied at suprathreshold levels. The stutterers and normal speakers performed similarly on all aspects of the magnitude-estimation scaling tasks, but the amount of threshold shift occurring during the scaling procedures was significantly greater for the stutterers at each suprathreshold intensity level employed.

Lingual Vibrotactile Threshold Shift during Magnitude-Estimation Scaling: Effects on Magnitude-Estimation Responses and Scaling Behavior across Age

The purpose of this study was to investigate the effects of age on tactile threshold shifts occurring during magnitude-estimation scaling of vibratory stimuli presented to the dorsal surface of the tongue. Relationships of the lingual vibrotactile threshold shifts to suprathreshold stimulus intensity, magnitude-estimation responses, and over-all scaling behavior were explored. Three groups differing in mean age participated in this study (Group 1 8.05 yr., Group 2 19.46 yr., and Group 3 56.2 yr.). Each subject performed two magnitude-estimation tasks. In one task, threshold of sensitivity was measured after every suprathreshold numerical response to the subject. If a threshold shift was recorded, threshold was allowed to return to the pretest baseline level continuing to the next suprathreshold stimulus presentation. The results showed that threshold shift during magnitude-estimation scaling took place for all three age groups and that the shift was related to the intensity of the suprathreshold vibratory stimulus being applied to the tongue. They also showed that Group 2 (young adults) performed magnitude-estimation scaling differently when threshold shift was controlled than when it was not. The other two groups of subjects were not similarly affected.

EFFECTS OF AUDITORY DISRUPTION OF LINGUALTACTILE SENSITIVITY IN SKILLED AND UNSKILLED SPEAKING CONDITIONS

The purpose of this study was to investigate the effect of disruption of the auditory feedback channel on lingual vibrotactile thresholds obtained under skilled and unskilled speaking conditions. Each of 22 adults was asked to read an English (skilled) and French (unskilled) passage under conditions of normal and altered auditory feedback. Bilateral presentation of masking noise was utilized to disrupt auditory feedback. Before each of the experimental sessions and immediately following a reading, lingual vibrotactile thresholds were obtained. Analysis indicated that the mean differences in the pre- and postvibrotactile threshold measurements of the skilled auditory disrupted condition varied significantly from the mean differences in the pre- and postvibrotactile threshold measurements of the three other conditions. The role of feedback in the speech production of skilled and unskilled speakers is discussed.

Lingual vibrotactile threshold shift during magnitude-estimation scaling: effects on magnitude-estimation responses and scaling behavior.

The purpose of the present study was to determine if lingual vibrotactile threshold shifts occurred during magnitude-estimation scaling of suprathreshold stimuli presented to the dorsal surface of the tongue. Possible relationships of the lingual vibrotactile threshold shifts to suprathreshold stimulus intensity, magnitude-estimation responses, and overall scaling behavior were explored. A single group of 24 subjects with an age range of 18 to 22 years participated in this study. Each subject performed two magnitude-estimation tasks. In one of the tasks, threshold of sensitivity was determined after every suprathreshold numerical response of the subject. If a threshold shift was recorded, threshold was allowed to return to the pretest baseline level before continuing to the next suprathreshold stimulus presentation. The results showed that threshold shift did occur during lingual vibrotactile magnitude-estimation scaling, and that it was related to suprathreshold stimulus intensity. The results also showed that the numerical magnitude-estimation responses of the subjects were different for the two scaling tasks. Overall scaling behavior of the subjects in the form of power-function exponents was not different for the two tasks.

Effect of auditory masking on lingual vibrotactile thresholds and magnitude estimation scaling responses.

Auditory masking has become a frequently employed part of the procedure used in vibrotactile research. Research investigating the effect of auditory masking on lingual vibrotactile thresholds of sensitivity has shown that there is little difference between lingual vibrotactile thresholds under masking and no masking conditions. The purpose of the present study was to extend the investigation of the effect of auditory masking to include lingual vibrotactile suprathreshold scaling responses. 20 young adult subjects of mean age 19 yr. completed lingual vibrotactile-threshold and magnitude-estimation scaling tasks under conditions of bilateral auditory masking and no masking. Similar lingual vibrotactile-threshold values and magnitude-estimation power-function exponents for the conditions of masking and no masking were noted.

Lingual vibrotactile screening: an investigation of normal sensitivity based on multiple threshold determinations.

This report describes a standardized training and sensory screening procedure which was used to obtain 7 separate lingual vibrotactile thresholds for each of 5 normal subjects during a 30-day interval. Baseline observations of lingual sensitivity were highly consistent and occurred within a narrow range of contractor displacements. The authors conclude that the screening method provides a quick and reliable clinical tool for general diagnostic use and discuss directions for continued research applications.

Oral vibrotactile screening: Reliability of low-frequency lingual vibrotactile thresholds obtained for two baseline conditions

The investigation evaluated the reliability of lingual vibrotactile thresholds obtained across two baseline conditions separated by an average of 14 days. Each baseline condition included three awareness training procedures as well as determination of the median of three vibrotactile thresholds. Results indicated a high degree of individual and intergroup threshold consistency. The authors view the technique as a possible screening procedure for general diagnostic use with adults. A discussion featuring specific future research needs is included.

Low-frequency adaptation and recovery effects for lingual vibrotactile thresholds

Lingual vibrotactile threshold adaptation and recovery effects were investigated. Three minutes of continuous vibrotactile stimulation preceded each of three experimental threshold trials. During recovery, three threshold trials followed rest periods of 1.5, 3.0, and 4.5 min. A control group performed the same tasks with no adaptor stimulus. The experimental subjects showed significant threshold decay from baselines, with subsequent recovery. The control subjects’ thresholds remained consistent with baselines. Implications for clinical oral sensory integrative testing are presented.

Threshold and suprathreshold correlations for the oral tactile sensory mechanism.

The possible relationship between threshold and suprathreshold responses for the lingual tactile system was investigated. Lingual vibrotactile thresholds and suprathreshold magnitude function exponents were correlated for 26 adult subjects. A statistical analysis of the correlations indicated that there was no significant relationship between thresholds and exponents. Vibrotactile threshold and suprathreshold information may be useful in increasing understanding of the complexities of oral somesthesis.

Stimulus pulse number effect on lingual vibrotactile thresholds

The present pilot investigation was designed to study the effects of pulse number on lingual vibrotactile thresholds when two different contactor sizes were employed. The results suggested that a temporal summation effect occurs with an increase in pulse repetition rate and contactor size. These findings are indicative of a need for future work involving summation measures as a basis for investigating the neurological integrity of the lingual sensory system.

Threshold and magnitude exponent function correlations for the human tongue

This study was designed to investigate possible relationships between threshold and suprathreshold lingual tactile processes, and to determine how accurately mean suprathreshold scaling values represent the behavior of individual subjects. Lingual vibrotactile threshold and suprathreshold values were obtained from 26 normal young adults. Results indicated that there was no statistically significant correlation between the threshold and suprathreshold data. It was also determined that mean sensation magnitude values may not accurately represent the behavior of individual subjects.

Effects of practice and instructional set on the measurement of lingual vibrotactile thresholds.

The effects on lingual vibrotactile thresholds of three different instructional sets and three different practice conditions were determined for 30 normal adult subjects. Results showed no measurable differences between thresholds obtained with the use of the three different instructional sets, but a high false alarm rate occurred for all conditions. When a subject was given practice at obtaining thresholds with a particular instructional set as a prerequisite to threshold data collection, false alarm responses disappeared. Lower (more sensitive) thresholds also were achieved when the practice condition used required the subject to provide three thresholds within 1 mu of each other before commencing with actual testing.

A precision method for lingual vibrotactile threshold measurement

This study was designed to evaluate the possible effect of two different psychophysical techniques on lingual vibrotactile sensory thresholds. Ten subjects were tested using the ascending psychophysical method of limits and the forced-choice signal detection technique of threshold assessment. Results indicated that both techniques provided consistent, reliable threshold data, but the forced-choice method yielded lower (more sensitive) lingual sensory thresholds. Results are discussed with respect to the appropriate utilization of both testing procedures.

The effects of stimulus pulse rise-decay time and duration on lingual vibrotactile thresholds

The present study consisted of two experimental phases. In Experiment 1, the effects on lingual vibrotactile threshold of four different stimulus pulse rise-decay times were investigated for 10 normal adult subjects. The results showed no statistically significant differences between thresholds obtained with the use of the four rise-decay times. In Experiment 2, the effects on lingual vibrotactile threshold of four different stimulus pulse durations were investigated for 10 normal adult subjects. A statistically significant difference was noted between thresholds obtained with stimulus pulse durations of land 50 msec.

Changes in lingual sensitivity as a function of age and stimulus exposure time.

Effects of duration of stimulus exposure on lingual vibrotactile thresholds were examined across three groups of 10 subjects each (n = 30). Subjects were grouped according to age (child group, mean age = 10.1 yr.; young adult group, mean age = 21.9 yr.; elderly group, mean age = 76.0 yr.). Lingual vibrotactile threshold measurements were obtained for all subjects under 5 conditions of exposure (1, 2, 3, 4, and 5 sec.). Results showed statistically significant differences in threshold among all three age groups. As age increased, thresholds of lingual sensitivity increased (became poorer). Stimulus duration also created significant differences in threshold for all age groups. As stimulus duration increased, thresholds of lingual sensitivity decreased (became better). The children appeared to be the most stable across conditions whereas the elderly group appeared to be the most affected by stimulus duration.

Auditory masking effects on lingual vibrotactile thresholds as a function of age.

Auditory masking effects on lingual vibrotactile thresholds were examined across three groups of 10 subjects each. The first group included children 13 yr. of age or younger, the second group young college age adults, and the third group elderly individuals 66 yr. of age or older. Lingual vibrotactile thresholds were obtained from each group at a frequency of 250 Hz, under experimental conditions of no-masking, narrow-band masking, and wide-band masking. Results showed statistically significant threshold differences between the elderly group and the other two groups for all three experimental conditions. A difference was also detected between experimental conditions when an over-all statistical analysis was performed, but this difference disappeared under more stringent post hoc examination. Results are discussed with respect to current literature on aging and appropriate simplified procedures are recommended for future lingual vibrotactile threshold testing.