Richard J. Klich

Providing basic hearing tests using remote computing technology.

We administered pure tone and otoacoustic emissions testing to subjects in a distant community using remote computing technology. Fifteen men and 15 women ranging in age from 18–30 years were tested. An audiometer was used to measure subject pure tone thresholds. In addition, distortion product otoacoustic emissions (DPOAEs) data were recorded using a portable system. Both systems were interfaced to a PC which was connected to the local area network at Minot State University (MSU). An examiner at Utah State University, 1100 km away, could control both the DPOAE and the audiometer equipment at MSU. Overall, the pure tone means for the face-to-face and telemedicine trials were equivalent at each frequency. Moreover, DPOAE recordings exhibited equivalent results at each frequency for telemedicine and face-to-face trials. These results support the use of remote computing as a telemedicine method for providing pure tone audiometry and DPOAE testing to distant communities.

Articulatory and phonological aspects of consonant substitutions in apraxia of speech.

The articulatory and distinctive features in 825 consonant substitutions produced by nine subjects with apraxia of speech were analyzed. The articulatory and distinctive features of the target consonants were retained beyond chance levels. The substitution patterns observed were very systematic in that more substitutions were made in the initial word position and stops, alveolars, and voiced consonants were used most often as substitutes for target consonants. The retention and usage of the features in the substitutions were closely related to the phonological markedness of the features, Most of the markedness changes were from marked-to-unmarked. The relationships between distinctive features and their markedness suggest that apraxia of speech is primarily a phonological disorder that is manifested in articulatoriy changes. It appears therefore that speakers with apraxia of speech systematically reduce linguistic complexity and simplify the production of consonants. In addition, the substitutions made in apraxia of speech are similar to those made by children.

Telemedicine for audiology screening of infants

Summary Distortion product otoacoustic emissions (DPOAE) and automated auditory brainstem response (AABR) screening were conducted in infants at a distant hospital using remote computing. Eighteen males and twelve females ranging in age from 11–45 days were tested. Both DPOAE and AABR data were recorded using an integrated test system which was connected to the computer network at the Utah Valley Regional Medical Center. Using a broadband Internet connection, an examiner at Utah State University, 200 km away, could control the DPOAE and the ABR equipment. Identical hearing screening results were obtained for face-to-face and telemedicine trials with all infants. The DPOAE means for face-to-face and telemedicine trials were not significantly different at any frequency. In an analysis of variance, there was no significant difference for the test method (F = 0.8, P > 0.05). These results indicate that remote computing is a feasible telemedicine method for providing DPOAE and ABR hearing screening services to infants in rural communities.

Syntax influences the accuracy of consonant production in language-disordered children.

Nine children with restricted syntactic and phonological development repeated 20 target consonants embbedded in noun phrase, simple declarative, and passive structures to determine the influence of syntactic complexity on accuracy of consonant production. The children made significantly more errors in the sentence contexts than in the noun phrase context. This was found for both early-developing and late-developing consonants. However, the ratio of the number of distinctive feature modifications to the number of consonant errors showed that segmental errors were not produced as less exact approximations of the target consonants. Instead, the children simply made more errors of a predictable type, suggesting that the effect of syntax on accuracy of consonant production is quantitative rather than qualitative.

Word length effects on EMG/Vowel duration relationships in apraxic speakers

The effects of word length on the timing of lip electromyographic (EMG) activity for production of the vowel /u/ and the relationship of this activity to vowel duration were examined in matched male and female pairs of normal and apraxic speakers. Both apraxic speakers had suffered left cerebrovascular accidents, which resulted in apraxia of speech as the primary communication deficit. For all participants, the interval of time in which lip muscle activity was present prior to the onset of voicing for the /u/ (EMG onset interval) in each word systematically decreased as word length increased. However, EMG activity offset intervals, which were measured from the onset of voicing for /u/ to the onset of the reduction of EMG activity during the vowel (EMG termination interval), decreased as word length increased only for the normal speakers. Relative onset of EMG activity was not significantly related to relative offset of EMG activity or relative vowel duration. However, the relative EMG onset interval was correlated with the duration of an entire word. Findings for the relative EMG termination interval were variable and are discussed relative to the severity of apraxia of speech.