Limits...
Tactile feedback improves auditory spatial localization.

Gori M, Vercillo T, Sandini G, Burr D - Front Psychol (2014)

Bottom Line: Control tests with the subject rotated suggested that this effect occurs only when the tactile and acoustic sequences are spatially congruent.Our results suggest that the tactile system can be used to recalibrate the auditory sense of space.These results encourage the possibility of designing rehabilitation programs to help blind persons establish a robust auditory sense of space, through training with the tactile modality.

View Article: PubMed Central - PubMed

Affiliation: Robotics Brain and Cognitive Sciences Department, Istituto Italiano di Tecnologia Genoa, Italy.

ABSTRACT
Our recent studies suggest that congenitally blind adults have severely impaired thresholds in an auditory spatial bisection task, pointing to the importance of vision in constructing complex auditory spatial maps (Gori et al., 2014). To explore strategies that may improve the auditory spatial sense in visually impaired people, we investigated the impact of tactile feedback on spatial auditory localization in 48 blindfolded sighted subjects. We measured auditory spatial bisection thresholds before and after training, either with tactile feedback, verbal feedback, or no feedback. Audio thresholds were first measured with a spatial bisection task: subjects judged whether the second sound of a three sound sequence was spatially closer to the first or the third sound. The tactile feedback group underwent two audio-tactile feedback sessions of 100 trials, where each auditory trial was followed by the same spatial sequence played on the subject's forearm; auditory spatial bisection thresholds were evaluated after each session. In the verbal feedback condition, the positions of the sounds were verbally reported to the subject after each feedback trial. The no feedback group did the same sequence of trials, with no feedback. Performance improved significantly only after audio-tactile feedback. The results suggest that direct tactile feedback interacts with the auditory spatial localization system, possibly by a process of cross-sensory recalibration. Control tests with the subject rotated suggested that this effect occurs only when the tactile and acoustic sequences are spatially congruent. Our results suggest that the tactile system can be used to recalibrate the auditory sense of space. These results encourage the possibility of designing rehabilitation programs to help blind persons establish a robust auditory sense of space, through training with the tactile modality.

No MeSH data available.


The effect of feedback on auditory bisection thresholds. (A) Tactile feedback. The three data points in the left-hand graph plot average thresholds measured before the feedback sessions (PRE), after the first feedback session (POST1) and after the second session (POST2). The stars indicate a significant difference level of p < 0.05 (one tailed t-test, p = 0.02 after the first feedback; one tailed t-test, p = 0.01 after the second feedback). The plot at right shows the thresholds for all subjects, plotting the thresholds after the second feedback (POST2) against the initial thresholds (PRE). All points fall below the equality line, showing that all subjects improved after feedback sessions. (B) Same as (A) for the no feedback condition. (C). Same as (A) for the verbal feedback condition.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4202795&req=5

Figure 3: The effect of feedback on auditory bisection thresholds. (A) Tactile feedback. The three data points in the left-hand graph plot average thresholds measured before the feedback sessions (PRE), after the first feedback session (POST1) and after the second session (POST2). The stars indicate a significant difference level of p < 0.05 (one tailed t-test, p = 0.02 after the first feedback; one tailed t-test, p = 0.01 after the second feedback). The plot at right shows the thresholds for all subjects, plotting the thresholds after the second feedback (POST2) against the initial thresholds (PRE). All points fall below the equality line, showing that all subjects improved after feedback sessions. (B) Same as (A) for the no feedback condition. (C). Same as (A) for the verbal feedback condition.

Mentions: Inspection of the curves shows that the psychometric functions become steeper after the tactile feedback sessions, suggesting that precision increases after auditory-tactile spatial association. We take the steepness of the curve (given by the SD) as the estimate of thresholds. Figure 3 plots thresholds for the tactile, no feedback and verbal conditions. The graphs at left show average results, and those at right individual thresholds. Tactile feedback (Figure 3A on the left) caused a clear and significant improvement with feedback [repeated measures multi-comparison one way analysis of variance (ANOVA) F(2,30) = 5.18, p = 0.011]. Thresholds decreased from 14.3 ± 3.5° before feedback to 7.4 ± 1.1° after the first session (two tailed paired t-test, t10 = 2.3, p = 0.04), and to 6.0 ± 1.0° after the second session (two tailed paired t-test, t10 = 2.63, p = 0.02). Figure 3A on the right shows that thresholds improved for almost all subjects, with all except one data point falling below the equality line.


Tactile feedback improves auditory spatial localization.

Gori M, Vercillo T, Sandini G, Burr D - Front Psychol (2014)

The effect of feedback on auditory bisection thresholds. (A) Tactile feedback. The three data points in the left-hand graph plot average thresholds measured before the feedback sessions (PRE), after the first feedback session (POST1) and after the second session (POST2). The stars indicate a significant difference level of p < 0.05 (one tailed t-test, p = 0.02 after the first feedback; one tailed t-test, p = 0.01 after the second feedback). The plot at right shows the thresholds for all subjects, plotting the thresholds after the second feedback (POST2) against the initial thresholds (PRE). All points fall below the equality line, showing that all subjects improved after feedback sessions. (B) Same as (A) for the no feedback condition. (C). Same as (A) for the verbal feedback condition.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4202795&req=5

Figure 3: The effect of feedback on auditory bisection thresholds. (A) Tactile feedback. The three data points in the left-hand graph plot average thresholds measured before the feedback sessions (PRE), after the first feedback session (POST1) and after the second session (POST2). The stars indicate a significant difference level of p < 0.05 (one tailed t-test, p = 0.02 after the first feedback; one tailed t-test, p = 0.01 after the second feedback). The plot at right shows the thresholds for all subjects, plotting the thresholds after the second feedback (POST2) against the initial thresholds (PRE). All points fall below the equality line, showing that all subjects improved after feedback sessions. (B) Same as (A) for the no feedback condition. (C). Same as (A) for the verbal feedback condition.
Mentions: Inspection of the curves shows that the psychometric functions become steeper after the tactile feedback sessions, suggesting that precision increases after auditory-tactile spatial association. We take the steepness of the curve (given by the SD) as the estimate of thresholds. Figure 3 plots thresholds for the tactile, no feedback and verbal conditions. The graphs at left show average results, and those at right individual thresholds. Tactile feedback (Figure 3A on the left) caused a clear and significant improvement with feedback [repeated measures multi-comparison one way analysis of variance (ANOVA) F(2,30) = 5.18, p = 0.011]. Thresholds decreased from 14.3 ± 3.5° before feedback to 7.4 ± 1.1° after the first session (two tailed paired t-test, t10 = 2.3, p = 0.04), and to 6.0 ± 1.0° after the second session (two tailed paired t-test, t10 = 2.63, p = 0.02). Figure 3A on the right shows that thresholds improved for almost all subjects, with all except one data point falling below the equality line.

Bottom Line: Control tests with the subject rotated suggested that this effect occurs only when the tactile and acoustic sequences are spatially congruent.Our results suggest that the tactile system can be used to recalibrate the auditory sense of space.These results encourage the possibility of designing rehabilitation programs to help blind persons establish a robust auditory sense of space, through training with the tactile modality.

View Article: PubMed Central - PubMed

Affiliation: Robotics Brain and Cognitive Sciences Department, Istituto Italiano di Tecnologia Genoa, Italy.

ABSTRACT
Our recent studies suggest that congenitally blind adults have severely impaired thresholds in an auditory spatial bisection task, pointing to the importance of vision in constructing complex auditory spatial maps (Gori et al., 2014). To explore strategies that may improve the auditory spatial sense in visually impaired people, we investigated the impact of tactile feedback on spatial auditory localization in 48 blindfolded sighted subjects. We measured auditory spatial bisection thresholds before and after training, either with tactile feedback, verbal feedback, or no feedback. Audio thresholds were first measured with a spatial bisection task: subjects judged whether the second sound of a three sound sequence was spatially closer to the first or the third sound. The tactile feedback group underwent two audio-tactile feedback sessions of 100 trials, where each auditory trial was followed by the same spatial sequence played on the subject's forearm; auditory spatial bisection thresholds were evaluated after each session. In the verbal feedback condition, the positions of the sounds were verbally reported to the subject after each feedback trial. The no feedback group did the same sequence of trials, with no feedback. Performance improved significantly only after audio-tactile feedback. The results suggest that direct tactile feedback interacts with the auditory spatial localization system, possibly by a process of cross-sensory recalibration. Control tests with the subject rotated suggested that this effect occurs only when the tactile and acoustic sequences are spatially congruent. Our results suggest that the tactile system can be used to recalibrate the auditory sense of space. These results encourage the possibility of designing rehabilitation programs to help blind persons establish a robust auditory sense of space, through training with the tactile modality.

No MeSH data available.