Normal Auditory Feedback Research Articles

Speech self-monitoring in preschoolers: the effects of delayed auditory feedback on recitation.

39 3- to 6-yr.-old children counted to 10 or recited the alphabet with normal auditory feedback, and delays of 150, 350, and 550 msec. There were no age differences. In addition to affecting rate of speech, delay differentially influenced the prosody, intelligibility, and content of utterances. For both tasks and all delay intervals, delay slowed speaking and produced more prosodic disturbances than no delay. More disturbances of intelligibility occurred at the 350- and 550-msec. delays than under no or 150-msec. delay. Disturbances in the content of counting were greater than in the no-delay condition but did not differ across delays. For alphabet recitation, disturbances in content under delay were greater than under no delay and were greater at 350 and 550 msec. than at 150 msec. Thirty-four children lost track of what they were doing; 10 articulated confusion. Children as young as 3 years of age concurrently self-monitor their speech for content.

Speaking speed effects on delayed auditory feedback disruption of speech fluency.

24 Italian medical students performed a task of verbal fluency. 12 students (the control group) receiving Normal Auditory Feedback and 12 students receiving Delayed Auditory Feedback (delay of 200 msec.) performed six trials in six different experimental settings: normal or increased speaking rate, and, for each condition, once with bilateral input of the auditory feedback, once to the right ear, and once to the left ear. At the normal speaking rate, the disruptive effect of delayed feedback was confirmed. As the speaking rate increased, the total number of errors increased within the control group but decreased within the group given delayed feedback, although the total number of errors was always greater for the latter. In addition, speech was more disrupted when the auditory input was returned to the right ear (left hemisphere) for all the different conditions: Normal and Delayed Auditory Feedback, normal and increased speaking rate. In particular, the left hemisphere was less resistant to the disruptive effect of the delayed feedback than the right hemisphere. From these results, we suggest that, when speaking more quickly, one uses more central mechanisms of movement programming (cortical-cerebellum-thalamus-cortical, cortical-corpus striatum-thalamus-cortical, and cortical-thalamus-cortical circuits), or attentional control (cortico-reticular-cortical circuits) than peripheral mechanisms (tactile, proprioceptive, and acoustic circuits). This may explain the decreased disruptive influence of delayed auditory feedback on speed, fluency, and quality at increased speaking rates. Hemispheric specialization processes, however, may explain the more pronounced susceptibility of the left hemisphere or the less pronounced susceptibility of the right hemisphere during the delayed feedback condition. In fact, the former processes phonemic, grammatical, and lexical features of words whilst the latter is competent in using metaphors and prosody in controlling the emotional aspects of language. Moreover, the right hemisphere is more active on attentional tasks.

Quantitative electroencephalogram of posterior cortical areas of fluent and stuttering participants during reading with normal and altered auditory feedback.

In the left and right hemisphere, posterior quantitative electroencephalogram Beta band activity (13.5-25.5 Hz) of seven adult participants who stutter and seven age-matched normal controls was obtained while subjects read text under three experimental conditions of normal auditory feedback, delayed auditory feedback, and frequency-altered feedback. Data were obtained from surface electrodes affixed to the scalp using a commercial electrode cap. Electroencephalogram activity was amplified, band-pass analog-filtered, and then digitized. During nonaltered auditory feedback, stuttering participants displayed Beta band hyperreactivity, with the right temporal-parietal lobe region showing the greatest activity. Under conditions of delayed auditory feedback and frequency-altered auditory feedback, the stuttering participants displayed a decrease in stuttering behavior accompanied by a strong reduction in Beta activity for the posterior-temporal-parietal electrode sites, and the left hemisphere posterior sites evidenced a larger area of reactivity. Such findings suggest than an alteration in the electrical fields of the cortex occurred in the stuttering participants under both conditions, possibly reflecting changes in neurogenerator status or current dipole activity. Further, one could propose that stuttering reflects an anomaly of the sensory-linguistic motor integration wherein each hemisphere generates competing linguistic messages at hyperreactive amplitudes.

Production and Detection of Speech Errors in Silent, Mouthed, Noise-Masked, and Normal Auditory Feedback Speech

In this study subjects had to report their errors during the speeded production of tongue twister sentences in one of four speech conditions: silent, mouthed, noise-masked, and normal auditory feedback speech. In contrast to the other three conditions, silent speech comprises speech planning but no articulation. Error monitoring in the normal auditory feedback condition may occur both by means of an inner speech (prearticulatory) loop and by means of auditory feedback, whereas in the other conditions only the first channel is available. The results showed that reported error rates were roughly equal in the silent, mouthed, and noise-masked condition, with an increase in the normal auditory feedback condition. Significantly more phonemic-sized errors and disfluencies were reported with auditory feedback, whereas word errors were less frequent. Notwithstanding the differences with respect to error size, report rates for the individual error categories (e.g. anticipations, perseverations, substitutions, etc.) did not differ notably for the four conditions. Errors typically occurred at the same points across speech conditions. These results suggest that speech planning processes are similar in the four speech conditions. Moreover, actual motor execution (i.e. articulation) does not appear to be an important contributor to the error events under study. The main difference between conditions can be attributed to the available monitoring channels.

Delayed Auditory Feedback in Polyglot Simultaneous Interpreters

Twelve polyglot students of simultaneous interpretation and 12 controls (students of the faculty of Medicine) were submitted to a task of verbal fluency under amplified normal auditory feedback (NAF) and under three delayed auditory feedback (DAF) conditions with three different delay intervals (150, 200, and 250 msec). The control group showed a significant reduction in verbal fluency and a significant increase in the number of mistakes in all three DAF conditions. The interpreters′ group, however, did not show any significant speech disruption neither in the subjects′ mother tongue (L1) nor in their second language (L2) across ah DAF conditions. Interpreters′ general high verbal fluency along with their ability to pay less attention to their own verbal output make them more resistant to the interfering effects of DAF on speech.

Error monitoring in people who stutter: evidence against auditory feedback defect theories.

Several theories purport that people who stutter suffer a speech-auditory feedback defect. The disordered feedback creates the illusion that some kind of error has intruded into the speech flow. Stuttering then results from actions aimed to correct the suspected, but nonexistent, error. These auditory feedback defect theories thus predict deviant error detection performance in people who stutter during speech production. To test this prediction, subjects who stuttered and those who did not had to detect self-produced (phonemic) speech errors while speaking with normal auditory feedback and with the auditory feedback masked by white noise. The two groups did not differ significantly in error detection accuracy and speed, nor in false alarm scores. This opposes auditory feedback defect theories and suggests that the self-monitoring processes of people who stutter function normally. In a condition in which errors had to be detected in other-produced speech, i.e., while listening to a tape recording, subjects who stuttered did detect fewer errors. Whether this might signal some general phonological problem is discussed.

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.

Articulatory Fo perturbations and auditory feedback.

Singers are required to sing with a high degree of precision of fundamental frequency (Fo). Does this mean that they have learned to compensate for the change of pitch that has been described in speech during production of different vowels? Experienced choir singers sang sustained tones with a change of vowel in mid-tone. The fundamental frequency was measured, and the resulting Fo contours were evaluated with respect to Fo effects coincident with the vowel changes. The tasks were performed both with normal auditory feedback and with the auditory feedback masked by noise in headphones. The vowels (i) and (y) were found to be associated with higher Fo than other vowels. The irregularities in the Fo curves were somewhat larger in the absence of auditory feedback. This is consistent with findings during speech production. The instability in Fo, measured as the standard deviation over each tone, was also larger in the absence of feedback.

Sex difference in susceptibility to delayed auditory feedback in oral reading tasks

Sex difference in susceptibility to DAF (delayed auditory feedback) in oral reading of texts was investigated. Forty adults, 20 males and 20 females with normal speech and hearing abilities, read aloud two kinds of texts, one easy to read and the other difficult, under two conditions, NAF (normal auditory feedback) and DAF. Delays were 150, 200, 300, 400 and 500 ms and the feedback intensity was 90 dB in SPL at maximum. Susceptibility to DAF was defined as max magnitude of DAF Index under five DAF conditions (DAF Index = 1-CMR(tau)/CMR(0), where CMR was correct mora rate per second and tau the delay). As the results, the susceptibility was significantly higher in males than in females for easy texts. Sex difference of the feedback mechanism for articulation was clearer in easy texts than in difficult ones. It was suggested that the articulatory movement was more cognitively controlled by the route of auditory feedback in males than in females.

Short-term memory processes in counting

Four experiments examined the memory processes used to maintain location in a counting sequence. In Experiment 1, subjects who rapidly counted forward omitted many repeated-digit numbers (e.g., 77), as found previously with backward counting. Subjects in Experiment 2 counted backward with normal auditory feedback or with headphones through which white noise was channeled. In both cases, repeated-digit errors predominated, suggesting that the contents of short-term memory, rather than auditory sensory memory, are checked during counting. In Experiment 3, subjects silently wrote counting responses, and the omission errors resembled those in vocal counting. Repetition errors were also found and attributed to phonological recoding failures. Articulatory suppression in Experiment 4 greatly increased the number of repetition errors in the written counting task. A model of the counting process was proposed according to which subjects keep track of their location in the counting sequence by monitoring phonologically coded short-term memory representations of the numbers.

Symptom improvement of spastic dysphonia in response to phonatory tasks.

It has been acknowledged that for many patients with spastic dysphonia, reflexive phonation remains essentially free of the spasticity that characterizes this disorder. The purpose of this paper is to document the extent to which various phonatory tasks change the patient's voice. We retrospectively reviewed 37 patients with spastic dysphonia evaluated at the Center for Communication Disorders of Lenox Hill Hospital, New York, between 1977 and 1981. The patients' responses to various phonatory tasks were observed. These tasks were grouped into the following ten categories: noncommunicative vocalization, primitive communication, speech superimposed on noncommunicative phonation, communicative phonation with varied mode of vocal fold vibration, normal communicative phonation with unusual pitch, normal communicative phonation with unusual emphasis, normal communicative phonation with normal laryngeal adjustments, use of the vocal folds in an artistic manner, speech in which normal auditory feedback was eliminated, and speaking with whisper which was not associated with vocal fold vibration. The results are summarized as follows: 1) whispered speech always resulted in an improvement of the symptom, in most cases markedly; 2) there was a tendency for a task that was more effective in reducing spasticity to be reduced in communicative function; 3) there was a tendency for a task that was more effective in reducing the spasticity to deviate more from the normal mode of phonation; and 4) there were some patients in whom an improvement occurred with elimination of auditory feedback.

Effects of frequency-shifted feedback on the pitch of vocal productions.

Previous investigations into the effects of distorted auditory feedback on vocalizations have been limited to manipulations of intensity, background noise, temporal delay, or to selective filtering of frequency. The current study reports the results of real-time shifts of the frequency components of auditory feedback. Subjectively, such shifts are perceived primarily as an alteration in the fundamental frequency (F0) of the speech. Subjects performed a variety of tasks under conditions where they received either normal auditory feedback or frequency-shifted feedback. Under normal feedback conditions, subjects maintained approximately constant F0 as instructed. With frequency-shifted feedback, subjects attempted to compensate for the shift by adjusting their F0 up or down such that the resulting feedback appeared to be "normal."

The effects pitch‐distorbed feedback on vocal productions

Previous investigations into the effects of distorted auditory feedback on vocalizations have been limited to manipulations of intensity, background noise, or delay in arrival time. The current study reports the results of real‐time distortions of the frequency components of auditory feedback. Subjectively, such distortion is perceived primarily as an alteration in the fundamental frequency of the speech. Subjects performed a variety of tasks under conditions where they received either normal auditory feedback (NAF) or pitch‐altered feedback (PAF). NAF performance was consistently good; PAF performance was quite poor. Subjects attempted to compensate for the frequency alterations by adjusting their fundamental frequency up or down such that the resulting feedback appeared to be “normal.” [Work supported by NSF.]

Familiarity of Reading Materials and the Delayed Auditory Feedback Effect

Delayed auditory feedback (DAF) effect was studied with the reading materials of different levels in familiarity, i.e. meaningful words and non-sense syllables, practiced and not practiced. Normal subjects with no stuttering habits (30 boys and 30 girls of the 6th grades of a primary school were equally divided into three groups) read the given materials under NAF (normal auditory feedback) and DAF conditions for testing DAF condition and fluency. The materials for Group 1 were 9 familiar meaningful words, while those for Group 2 and Group 3 were 9 unfamiliar non-sense syllables respectively. Group 3, however, was tested after ten times practice in reading the materials. DAF effect was defined by the formula, 1- CMR under DAF/CMR under NAF (CMR was the correct morae rate of reading per second) . DAF effect in Group 1 was found significantly less than that in Group 2 but there was no significant difference between Groups 2 and 3. The results were discussed and evaluated external and internal feedback models for speech control.

THE EFFECTS OF DELAYED AUDITORY FEEDBACK (DAF) ON PATIENTS WITH UNILATERAL HEMISPHERIC DAMAGE

This study was conducted with the aim of evaluating the effect of delayed auditory feedback (DAF) on patients with unilateral hemispheric damage. The experimental subjects consisted of three groups of 15 persons: normal male subjects in their fifties, the patients with left sided hemispheric damage and these with the right sided respectively. Each subject was asked to read a list consisting of 50 Japanese syllables under NAF (normal auditory feedback) and DAF with a delay of 0.2 seconds. The experiment was conducted by presenting DAF to one ear during the task with white noise masking the other ear. Two indices of DAF effect were employed: number of articulatory errors and total speaking time.As a result, a significantly greater number of articulatory errors occurred when presenting DAF to the ipsilateral ear of hemispheric damage than to the contralateral. In the measurement of total speaking time, however, no significant differences between the ears were found.

Timed auditory interruption during speech: oral sensory and temporal articulatory changes

Recent investigations have demonstrated that subjects speaking under exposure to masking noise demonstrate decreases in oral sensory function and temporal reorganization of the articulatory pattern. The present study was an attempt to measure the effects of this phenomenon under varying durations of exposure to auditory masking. To assess changes in oral sensory function, lingual vibrotactile thresholds were obtained from subjects in two conditions: (1) after reading for various time intervals under exposure to 90 dB SPL babble noise, and (2) after reading for various time intervals with normal auditory feedback. Temporal changes in the articulatory pattern were assessed by obtaining duration measurements of selected speech segments from each exposure interval. Results indicated that lingual sensory changes and temporal reorganization occurred only in conditions involving disruption of auditory feedback. The changes in lingual thresholds followed a pattern such that sensitivity decreased as exposure interval increased. This trend was only mildly observed in temporal articulatory alterations. Temporal changes did demonstrate a consistent decrease in consonant duration and increase in vowel duration. The observed results are discussed in reference to physiological properties of the speech system and current theorics of sensory regulation of speech production.

The effects of delayed auditory feedback and masking on the fundamental frequency of stutterers and nonstutterers.

This investigation determined if fluency of the reader or type of auditory feedback changed characteristics of fundamental frequency or duration in oral reading by stutterers or nonstutterers. Mingographic tracings were made of sentences excerpted from tape recordings of paragraphs read by 15 adult male stutterers and 15 adult male nonstutterers in three conditions of feedback: normal auditory feedback (under earphones), delayed auditory feedback (0.14 sec delay), and masking (90 dB SPL). The data included 15 measures of fundamental frequency and two measures of duration. Stutterers read sentences in greater total time and with more downward inflections than nonstutterers. Comparison of the delayed auditory feedback (DAF) conditions with the normal auditory feedback (NAF) condition showed that the numbers of total, upward, and downward inflections and upward pitch shifts increased under DAF. In the DAF condition, average rates of upward and downward inflections decreased, and mean and median fundamental frequencies and total time increased. The only changes from the NAF to the masking condition were increases in mean and median fundamental frequencies.

The Effects of Delayed Auditory Feedback (DAF) on Normal Speakers and the Aphasics

There has been little investigation upon the experiment of delayed auditory feedback concerning speech of aphasic patients. This study was conducted with the aim of evaluating DAF as a possible tool for examining physiological aspects of aphasic speech and language.Normal speakers were 20 men in their fifties and the aphasics were 45 patients of 4 types—amnesic, conduction, sensory and motor — aged from 24 to 74 years. Each subject was asked to read a Japanese 50 syllable table under NAF (normal auditory feedback) and DAF condition with a delay time of 0.2 seconds and feedback level of 90 dB SPL to both ears.The responses of the aphasic patients to DAF were divided broadly into three groups;1) The response of the mild group (amnesic aphasia) was similar to that of a normal speaker — increased vocal intensity, reduced rate of utterance and syllable repetition.2) The response of the severe group (typical sensory or motor aphasia) was characterized by unaffected vocal intensity and articulatory errors in both NAF and DAF.3) The response of the moderate group (conduction aphasia) was in between the mild and the severe groups.

Effects of altering vowel feedback on speech movements

Delayed auditory feedback, masking and movement tracking techniques have been used to investigate the role of auditory feedback in speech production. The results of these experiments are not conclusive and questions still remain as to whether auditory feedback plays a role, when it plays a role and how it plays a role in speech production. In the present study it was hypothesized that if acoustic information concerning the articulatory positions relevant to vowel production is used in speech production, then altering vowel information would disrupt the movements to subsequent sounds in a C1V1C2V2 utterance. High‐speed cineradiography (150 fps) was used to monitor movements of the jaw, lips, and tongue. During their production of C1V1C2V2 utterances subjects received (1) normal auditory feedback; (2) feedback in which V1 was altered to another vowel; (3) high‐level masking noise. Displacements, velocities, and accelerations were calculated for articulatory movements to V1, C2, and V2 in each condition. The...

Study on Delayed Auditory Feedback (DAF) with Filtered Speech

The present study was aimed to evaluate the speech behaviors of normal young adults under DAF condition with an audiofilter.The feedback speech was distorted with a lowpass and a high-pass filter. The subjects were 21 young adults, 18 males and 13 females. Each subject read 100-word passages under DAF (delay time 200 msec) with all-pass filtering, low-pass filtering above 1, 200, 1, 700 and 2, 400Hz, and high-pass filtering below 1, 200, 1, 700 and 2, 400Hz. The feedback level was 65dB above each hearing threshold, and the sound was delivered to both ears. The speech behaviors were analysed with reference to reading time ratio and articulatory error, comparing with those under normal auditory feedback (NAF).The results were as follows:1. The speech behaviors were mostly disturbed under all-pass filtering.2. The speech behaviors under low-pass filtering were more disturbed than those under highpass filtering.3. There were little differences among speech behaviors under three conditions of filtering; 1, 200, 1, 700 and 2, 400Hz for low-pass and high-pass respectively.4. In general, the DAF effects on the male were greater than the female.5. It was concluded that the low frequency range of speech sound was mostly responsible for DAF effect.