Phoneme Identification Test Research Articles

The effect of phoneme-based auditory training on speech intelligibility in hearing-aid users

Objective Hearing loss commonly causes difficulties in understanding speech in the presence of background noise. The benefits of hearing-aids in terms of speech intelligibility in challenging listening scenarios remain limited. The present study investigated if phoneme-in-noise discrimination training improves phoneme identification and sentence intelligibility in noise in hearing-aid users. Design Two groups of participants received either a two-week training program or a control intervention. Three phoneme categories were trained: onset consonants (C1), vowels (V) and post-vowel consonants (C2) in C1-V-C2-/i/ logatomes from the Danish nonsense word corpus (DANOK). Phoneme identification test and hearing in noise test (HINT) were administered before and after the respective interventions and, for the training group only, after three months. Study sample Twenty 63-to-79 years old individuals with a mild-to-moderate sensorineural hearing loss and at least one year of experience using hearing-aids. Results The training provided an improvement in phoneme identification scores for vowels and post-vowel consonants, which was retained over three months. No significant performance improvement in HINT was found. Conclusion The study demonstrates that the training induced a robust refinement of auditory perception at a phoneme level but provides no evidence for the generalisation to an untrained sentence intelligibility task.

Recalibration of auditory perception of speech due to orofacial somatosensory inputs during speech motor adaptation.

Speech motor control and learning rely on both somatosensory and auditory inputs. Somatosensory inputs associated with speech production can also affect the process of auditory perception of speech, and the somatosensory-auditory interaction may play a fundamental role in auditory perception of speech. In this report, we show that the somatosensory system contributes to perceptual recalibration, separate from its role in motor function. Subjects participated in speech motor adaptation to altered auditory feedback. Auditory perception of speech was assessed in phonemic identification tests before and after speech adaptation. To investigate a role of the somatosensory system in motor adaptation and subsequent perceptual change, we applied orofacial skin stretch in either a backward or forward direction during the auditory feedback alteration as a somatosensory modulation. We found that the somatosensory modulation did not affect the amount of adaptation at the end of training, although it changed the rate of adaptation. However, the perception following speech adaptation was altered depending on the direction of the somatosensory modulation. Somatosensory inflow rather than motor outflow thus drives changes to auditory perception of speech following speech adaptation, suggesting that somatosensory inputs play an important role in tuning of perceptual system.NEW & NOTEWORTHY This article reports that the somatosensory system works not equally with the motor system, but predominantly in the calibration of auditory perception of speech by speech production.

Investigating Auditory Spectral and Temporal Resolution Deficits in Children with Reading Difficulties.

The types of reading difficulties experienced by children are highly heterogeneous in nature, which makes diagnosis and intervention difficult. Over the past 30 years, there has been much debate over the cause of dyslexia. The two most popular theories for phonological deficits in dyslexia are the rate-processing constraint hypothesis, which relates to short timescale processing, and the temporal sampling framework hypothesis, which relates to longer timescale processing. To investigate the relationship between sublexical (i.e., nonword) reading skills and auditory spectral and temporal resolution patterns in children with reading difficulties using the Phoneme Identification Test (PIT) and the Parsing Syllable Envelopes Test (ParSE). These tests were developed to assess the rate-processing constraint and the temporal sampling framework hypotheses, respectively. We hypothesized that a proportion of children who have sublexical reading difficulties may have an underlying auditory-resolution deficit which may impact their ability to form letter-sound correspondences. We predicted that children's sublexical reading difficulties may not be explained by one theory, but instead that both theories may describe different types of reading difficulties found in different children. We also hypothesized that children with lexical (i.e., irregular word) reading difficulties but intact sublexical reading skills would not show atypical results on PIT or ParSE. Behavioral experimental clinical study with children who have reading difficulties. Sixteen children with nonword, irregular word, or mixed reading difficulties diagnosed by the Castles and Coltheart Test 2. Children completed a test battery consisting of a hearing screen and tests of reading, auditory resolution, phonological awareness, attention, spatial auditory processing, auditory memory, and intelligence. Categorization and correlational analyses were conducted. All four children with a pure sublexical reading deficit also had an auditory-resolution deficit. Four of seven children with a mixed reading deficit had an auditory-resolution deficit. Only one of five children with a lexical reading deficit had an auditory-resolution deficit. Individual children's specific deficits were related to either rate processing (n = 5) or temporal sampling (n = 4), but never both. Children's nonword reading scores were strongly correlated with their performance on the PIT in noise, but not with the PIT in quiet or the ParSE. Children's irregular word scores were not significantly correlated with their performance on the PIT in quiet or in noise, or the ParSE, as hypothesized. Strong correlations were also found between children's nonword scores and their phonological awareness scores. The results of this study suggest that neither the rate-processing hypothesis nor the temporal sampling framework is the single cause of reading difficulties in children. Instead, both of these hypotheses are likely to account for different types of reading deficits found in children. This is an important finding as the specific mechanisms driving different reading impairments must be identified to create tools to better diagnose and treat different types of reading difficulties. Further investigation of the PIT and ParSE as potential diagnostic tools for specific auditory-resolution-based reading difficulties in a larger group of children is currently underway.

Brain Plasticity Can Predict the Cochlear Implant Outcome in Adult-Onset Deafness.

Sensory plasticity, which is associated with deafness, has not been as thoroughly investigated in the adult brain as it has in the developing brain. In this study, we examined the brain reorganization induced by auditory deprivation in people with adult-onset deafness and its clinical relevance by measuring glucose metabolism before cochlear implant (CI) surgery. F-18 fluorodeoxyglucose positron emission tomography (18F-FDG-PET) scans were performed in 37 postlingually deafened patients during the preoperative workup period, and in 39 normal-hearing (NH) controls. Behavioral CI outcomes were measured at 1 year after implantation using a phoneme identification test with auditory cueing only. In the deaf individuals, areas involved in the auditory pathway such as the inferior colliculus and bilateral superior temporal gyri were hypometabolic compared to the NH controls. The hypometabolism observed in the deaf auditory cortices gradually returned to levels similar to the controls as the duration of deafness increased. However, contrary to our previous findings in congenitally deaf children, this metabolic recovery failed to have a significant prognostic value for the recovery of the speech perception ability in adult CI patients. In a broad occipital area centered on the primary visual cortices, glucose metabolism was higher in the deaf patients than the controls, suggesting that the area had become visually hyperactive for sensory compensation immediately after the onset of deafness. In addition, a negative correlation between the metabolic activity and behavioral speech perception outcomes was observed in the visual association areas. In the medial frontal cortices, cortical metabolism in most patients decreased, but patients who had preserved metabolic activities showed better speech performance. These results suggest that the auditory cortex in people with adult-onset deafness is relatively resistant to cross-modal plasticity, and instead, individual traits in late-stage visual processing and cognitive control seem to be more reliable prognostic markers for adult-onset deafness.

The Phoneme Identification Test for Assessment of Spectral and Temporal Discrimination Skills in Children: Development, Normative Data, and Test-Retest Reliability Studies.

Previous research suggests that a proportion of children experiencing reading and listening difficulties may have an underlying primary deficit in the way that the central auditory nervous system analyses the perceptually important, rapidly varying, formant frequency components of speech. The Phoneme Identification Test (PIT) was developed to investigate the ability of children to use spectro-temporal cues to perceptually categorize speech sounds based on their rapidly changing formant frequencies. The PIT uses an adaptive two-alternative forced-choice procedure whereby the participant identifies a synthesized consonant-vowel (CV) (/ba/ or /da/) syllable. CV syllables differed only in the second formant (F2) frequency along an 11-step continuum (between 0% and 100%-representing an ideal /ba/ and /da/, respectively). The CV syllables were presented in either quiet (PIT Q) or noise at a 0 dB signal-to-noise ratio (PIT N). Development of the PIT stimuli and test protocols, and collection of normative and test-retest reliability data. Twelve adults (aged 23 yr 10 mo to 50 yr 9 mo, mean 32 yr 5 mo) and 137 typically developing, primary-school children (aged 6 yr 0 mo to 12 yr 4 mo, mean 9 yr 3 mo). There were 73 males and 76 females. Data were collected using a touchscreen computer. Psychometric functions were automatically fit to individual data by the PIT software. Performance was determined by the width of the continuum for which responses were neither clearly /ba/ nor /da/ (referred to as the uncertainty region [UR]). A shallower psychometric function slope reflected greater uncertainty. Age effects were determined based on raw scores. Z scores were calculated to account for the effect of age on performance. Outliers, and individual data for which the confidence interval of the UR exceeded a maximum allowable value, were removed. Nonparametric tests were used as the data were skewed toward negative performance. Across participants, the median value of the F2 range that resulted in uncertain responses was 33% in quiet and 40% in noise. There was a significant effect of age on the width of this UR (p < 0.00001) in both quiet and noise, with performance becoming adult like by age 9 on the PIT Q and age 10 on the PIT N. A skewed distribution toward negative performance occurred in both quiet (p = 0.01) and noise (p = 0.006). Median UR scores were significantly wider in noise than in quiet (T = 2041, p < 0.0000001). Performance (z scores) across the two tests was significantly correlated (r = 0.36, p = 0.000009). Test-retest z scores were significantly correlated in both quiet and noise (r = 0.4 and 0.37, respectively, p < 0.0001). The PIT normative data show that the ability to identify phonemes based on changes in formant transitions improves with age, and that some children in the general population have performance much worse than their age peers. In children, uncertainty increases when the stimuli are presented in noise. The test is suitable for use in planned studies in a clinical population.

A Computer-Based, Word-Free Phoneme Identification Test Teetahtoo — Adaptation into Polish

The auditory processing of different phonemes is an important listening skill, which is usually already acquired in early childhood (Kuhl, 2004). These developments, in turn, affect a variety of other skills as speech development and normal acquisition of literacy skills (Eimas, 1985). Early detection and intervention of hearing disorders as well as advanced technology of auditory prosthesis like digital hearing aids and cochlear implants improve the auditory capabilities of hearing-impaired children. The achievement of skills like auditory discrimination and identification of phonemes become realistic objectives in the therapy of hearing-impaired children (Coninx & Moore, 1997). There is a lack of a well-defined and internationally comparable paediatric tests, assessing phoneme identification, in different languages as closely as possible comparable to each other. The aim of this work is to adopt to Polish language a computer-based, word-free phoneme identification test Teetahtoo, which evaluates a child‘s ability to discriminate and identify different phonemes. The Teetahtoo test was developed for German language by Frans Coninx (Coninx & Stumpf, 2005).

Covariation of cochlear implant users' perception and production of vowel contrasts and their identification by listeners with normal hearing.

This study investigates covariation of perception and production of vowel contrasts in speakers who use cochlear implants and identification of those contrasts by listeners with normal hearing. Formant measures were made of seven vowel pairs whose members are neighboring in acoustic space. The vowels were produced in carrier phrases by 8 postlingually deafened adults, before and after they received their cochlear implants (CI). Improvements in a speaker's production and perception of a given vowel contrast and normally hearing listeners' identification of that contrast in masking noise tended to occur together. Specifically, speakers who produced vowel pairs with reduced contrast in the pre-CI condition (measured by separation in the acoustic vowel space) and who showed improvement in their perception of these contrasts post-CI (measured with a phoneme identification test) were found to have enhanced production contrasts post-CI in many cases. These enhanced production contrasts were associated, in turn, with enhanced masked word recognition, as measured from responses of a group of 10 normally hearing listeners. The results support the view that restoring self-hearing allows a speaker to adjust articulatory routines to ensure sufficient perceptual contrast for listeners.

Speech perception, production, and intelligibility improvements in vowel-pair contrasts among adults who receive cochlear implants

This study investigates relations among speech perception, speech production, and intelligibility in postlingually deaf adults who receive cochlear implants (CI). Measures were made for seven vowel pairs that neighbor in acoustic space from eight postlingually deafened adults, pre- and postimplant. Improvements in a speaker’s production, perception, and intelligibility of a given vowel contrast tended to occur together. Subjects who produced vowel pairs with reduced contrast in the preimplant condition (measured by separation in the acoustic vowel space) and who showed improvement in their perception of these contrasts postimplant (measured with a phoneme identification test) were found to have improved production contrasts post-CI. These enhanced production contrasts were associated with enhanced intelligibility, as measured from responses of a group of normal-hearing listeners. The results support the hypothesis that the implant user’s improving speech perception contributes, at least in part, to that speaker’s improving speech production. [Work supported by the NIDCD, NIH.]

Tonal disruption in the speech of a language-delayed Thai adult

An acoustic-perceptual investigation was performed on fundamental frequency (F(0)) contours associated with lexical tones in the speech of one 21-year-old adult speaker of Thai who did not start speaking until age 7. Thai is a tone language with five lexically contrastive tones-mid, low, falling, high, and rising. Measures of F, were taken from a minimal set of five monosyllabic citation forms. Results from phonemic identification tests indicated that AY exhibited a selective disruption in the production of Thai tones. In contrast to the normal Thai tone space, AY's tone space was reduced to three tones-mid, low, and rising. Acoustic analysis revealed that AY�s aberrant F(0) contours for the falling and high tones were virtually identical in terms of height and overall shape; both exhibited a slow, steady fall in F(0) in the upper range of AY's tone space. Listeners' failure to perceive AY's intended productions of the falling and high tones confirmed the perceptual importance of rapid change in F(0) slope in the Thai tone space. Findings are discussed with reference to the chronological order in which Thai tones are acquired in normal language development.

Perception and production of tone in aphasia

An acoustical and perceptual study of lexical tone was conducted to evaluate the extent and nature of tonal disruption in aphasia. The language under investigation was Thai, a tone language which has five lexical tones— mid, low, falling, high, and rising. Subjects included six left brain-damaged aphasics (two Broca's, one transcortical motor, one global, one conduction, one Wernicke), one right brain-damaged nonaphasic, one cerebellar dysarthric, and five normals. High-quality tape recordings of each subject's productions of a minimal set of five, monosyllabic Thai words were presented to 10 adult Thai listeners for identification. Results from the phonemic identification tests indicated that tone production is relatively spared in aphasic patients with unilateral left hemisphere lesions. The performance of the global aphasic, however, was considerably below normal. Patterns of tonal confusions further revealed that the performance of all aphasics, except the global, differed from that of normal speakers primarily in degree rather than in kind. Tonal contrasts were signaled at a high level of proficiency by the right brain-damaged and dysarthric patients. Acoustical analysis revealed that F 0 contours associated with the five tones for all aphasics, except the global, were similar in overall shape as well as position in the tone space to those of normals. F 0 contours for the right brain-damaged patient and the dysarthric also generally agreed with those of normals in terms of shape and position. F 0 ranges of both aphasic and nonaphasic brain-damaged speakers were generally larger than those of normals for all five tones. The relationship between tone and vowel duration was generally similar to that of normals for all brain-damaged speakers. A comparison of aphasics' performance on tone perception ( J. Gandour & R. Dardarananda, 1983, Brain and Language, 18, 94–114 ) and tone production indicated that, for the normal and right brain-damaged subjects, performance on the perception task was higher than on production, whereas the opposite was true for the aphasics. These data are brought to bear on issues related to tone production in aphasia, consonant and vowel production in aphasia, hemispheric specialization for tone production, intonation production in aphasia, relationship between speech perception and speech production, and tone production in dysarthria with cerebellar disease.

Tone in Thai alaryngeal speech.

The perception and production of linguistic tone was investigated in utterances spoken by Thai alaryngeal speakers. Thai is a tone language with five phonemic tones. High-quality tape recordings of five monosyllabic words produced by 2 esophageal, 1 electrolaryngeal, and 5 normal, native Thai speakers were subjected to perceptual and acoustic analysis. Results from the phonemic identification tests indicated that tones produced by alaryngeal speakers were not only perceived at much lower levels of accuracy than those produced by normal speakers, but the patterns of tonal confusions for alaryngeal speakers were also dissimilar to those for normal speakers. Results from fundamental frequency (Fo) analysis revealed that the performance deficit of alaryngeal speakers could be related to specific characteristics of their Fo contours. Findings are interpreted to highlight the importance of (a) language, (b) type of prosody, (c) form of alaryngeal speech, and (d) Fo level and direction on linguistic assessments of Fo control in alaryngeal speech.

Tonal confusions in Thai patients with sensorineural hearing loss.

In a tone language, every syllable or word may have a distinctive pitch pattern as part of its phonemic composition. This study examined the extent and nature of impairment in the perception of phonemic tones by hearing-impaired listeners in Thai, a tone language that has five phonemic tones. Seventy-six subjects were assigned to four listener groups: normal-hearing (n = 21), mild-hearing-loss (n = 21), moderate-hearing-loss (n = 26), and severe-hearing-loss (n = 8). Five Thai words differing only in tone were presented for identification in both natural speech and synthetic speech versions. Results from the phonemic identification tests indicated that tonal identification is affected by the presence of sensorineural hearing loss. In particular, the number and often the type of tonal confusions made by Thai hearing-impaired listeners varied with the extent of hearing loss for both natural and synthetic speech versions. In contrast to previous findings on the patterns of consonant and vowel confusions in hearing-impaired listeners, the patterns of tonal confusions in hearing-impaired listeners can be related to the degree of hearing loss.

Multidimensional analysis of auditory and visual perception among the profoundly hearing impaired

Fifteen profoundly deaf subjects' responses on the Phoneme Identification Test Series were studied via HI CLUS and KYST multidimensional analysis techniques in order to determine whether meaningful perceptual dimensions were utilized by subjects in spite of very low scores for exact phoneme identification. Results suggested that this group of subjects tended to categorize their responses along a single feature for auditory perception. In a second experiment, deaf subjects' speechread responses to the Phoneme Identification Test were analyzed via HYCLUS. Results were like that of previous studies with normal or mildly hearing impaired, but an interesting visual dimension was discovered which allowed discrimination between the back consonants (k) and (g) for some S's. [Supported by HEW.]