Variation in articulatory timing of three English consonants: an electropalatographic investigation

Tongue-Palate Contact during Bilabials in Normal Speech

Objective:

Previous research using electropalatography (EPG) identified a compensatory articulation called bilabial-lingual double articulations. These double articulations were produced for bilabials by some speakers with cleft palate and involved closure at the lips occurring simultaneously with complete tongue-palate constriction. However, no normative English EPG data exist to confirm the abnormal status of these double articulations.

Design:

This study reports normative data for EPG contact during bilabial closure. Acoustic and EPG data were recorded for bilabials in different vowel contexts.

Participants:

Eight normal English-speaking adults.

Measures:

One measure identified complete tongue-palate constriction, and a second measure calculated percent contact.

Results:

There were no instances of complete tongue-palate constriction, though some EPG contact occurred in the lateral regions of the palate. The vowel context significantly affected the amount of contact present, with /i/ having the most and /a/ having the least amount of contact.

Conclusion:

Complete tongue-palate constriction during bilabials of the type found in bilabial-lingual double articulations is not a feature of normal English speech and can therefore be considered an abnormal articulation pattern. Speech-language pathologists who use EPG in their clinical work should be aware that some lateral contact during bilabial closure is normal.

Electropalatographic specification of Croatian fricatives /s/ and /z/

Electropalatographic specification of alveolar fricatives in Croatian is aimed at providing speech therapists with normative data about the range of acceptable productions of /s/ and /z/ in adult speakers of Croatian. Four variables were analysed: place of articulation, total contact, groove width and hold phase duration. Intra- and inter-speaker variability for each variable was analysed. Lingual palatal cues for voicing difference were also quantified and discussed. Results show that Croatian /s/ and /z/ are alveolar and not dental as previously reported. The comparison between the voiced and the voiceless fricative shows that durational measures provide the best differentiation. The voiceless counterpart is significantly longer. The difference between voiced and voiceless is also found in the total contact, with /z/ having more contact in the anterior four rows of electrodes, while /s/ has more contact in the posterior four rows of electrodes. This difference is also reflected in the anterior and the posterior groove widths. Possibilities of using these results as normative data for the diagnosis and treatment of atypical articulation of /s/ and /z/ are discussed.

Electropalatography in the description and treatment of speech disorders in five children with cerebral palsy

Some children with cerebral palsy have articulation disorders that are resistant to conventional speech therapy. The aim of this study was to investigate whether the visual feedback method of electropalatography (EPG) could be an effective tool for treating five children (mean age of 9.4 years) with dysarthria and cerebral palsy and to explore whether training improved the posteriorly placed articulation of the Swedish dental/alveolar target consonants /t/, /d/, /n/ and /s/ produced in different positions. An EPG analysis was conducted and some of the data were combined with a perceptual analysis. A more anterior placement was seen after treatment for the target sounds. Features of diagnostic importance revealed were unusual tongue-palate contacts, such as double articulation and abnormally retracted articulation. A possible change in stop closure duration was indicated. The results suggest that EPG could be of potential benefit for diagnosing, treating and describing articulation errors associated with cerebral palsy.

Electropalatography treatment for articulation impairment in children with dysarthria post-traumatic brain injury

PRIMARY OBJECTIVE

Dysarthria with severe articulatory impairment is a common and debilitating sequelae following severe traumatic brain injury (TBI). Eectropalatography (EPG) is an instrumental treatment technique allowing visual feedback of tongue to palate movement during real time articulation. The present study investigated the effectiveness of EPG in treating the articulatory component of dysarthria post-TBI.

STUDY DESIGN/METHODS

The articulatory component of dysarthria post-TBI was treated once per week with EPG over a 10-week period in three adolescents (aged 14 years 10 months-15 years 1 month). A multiple case series ABA treatment design was used. Perceptual (articulation, intelligibility) and EPG (spatial, durational) assessments were conducted pre- and post-treatment to determine outcome.

RESULTS/DISCUSSION

Perceptual improvement was noted for phoneme precision and length. Spatial EPG measures confirmed increased precision of phoneme production. No clear pattern of change for phoneme duration occurred. Intelligibility increased at word and sentence level, with little change reported in everyday speech intelligibility.

CONCLUSION

This preliminary study indicates that EPG treatment may be effective for improving speech at the isolated phoneme, word or sentence level of articulation. These preliminary results are encouraging, being the first study to report speech changes post-treatment in participants with severe TBI and persistent dysarthria. Further research is required, however, in order to understand the regenerative capacity of articulatory function post-brain injury and to determine optimal treatment parameters for achieving generalization of therapy to everyday connected speech.

Temporal features of articulation from childhood to adolescence: an electropalatographic investigation

This study was designed to investigate the development of articulatory timing from mid-childhood to late adolescence. Productions of sentences containing /t/, /l/, /s/, and /k/ were produced by 48 children and adults (aged 6-38 years) and captured using the Reading Electropalatography3 (EPG3) system. Mean duration of the sentences and the approach, closure/stable constriction, and release phases of consonant articulation were calculated. In addition, temporal coordination of lingual gestures and the intra-subject articulatory timing variation were investigated across the ages. Results reveal some distinct differences in duration and temporal coordination of lingual gestures between 6- to 7-year-olds and mature speakers, with continual refinement of articulatory control indicated into late adolescence. Differences in articulatory stability, in contrast, were not significant. The present findings may form a platform for development of a more descriptive model of motor speech development.

Adaptation to an electropalatograph palate: acoustic, impressionistic, and perceptual data

PURPOSE

The purpose of this study was to evaluate adaptation to the electropalatograph (EPG) from the perspective of consonant acoustics, listener perceptions, and speaker ratings.

METHOD

Seven adults with typical speech wore an EPG and pseudo-EPG palate over 2 days and produced syllables, read a passage, counted, and rated their adaptation to the palate. Consonant acoustics, listener ratings, and speaker ratings were analyzed.

RESULTS

The spectral mean for the burst (/t/) and frication (/s/) was reduced for the first 60-120 min of wearing the pseudo-EPG palate. Temporal features (stop gap, frication, and syllable duration) were unaffected by wearing the pseudo-EPG palate. The EPG palate had a similar effect on consonant acoustics as the pseudo-EPG palate. Expert listener ratings indicated minimal to no change in speech naturalness or distortion from the pseudo-EPG or EPG palate. The sounds [see text] were most likely to be affected. Speaker self-ratings related to oral comfort, speech, tongue movement, appearance, and oral sensation were negatively affected by the presence of the palatal devices.

CONCLUSIONS

Speakers detected a substantial difference when wearing a palatal device, but the effects on speech were minimal based on listener ratings. Spectral features of consonants were initially affected, although adaptation occurred. Wearing an EPG or pseudo-EPG palate for approximately 2 hr results in relatively normal-sounding speech with acoustic features similar to a no-palate condition.