Speech intelligibility of Flemish children as judged by their parents.

OBJECTIVE: Reduced intelligibility is a central concern in speech-impaired children, especially for parents. The main purpose of this study was to develop normative data for the intelligibility of Flemish-speaking boys and girls (age 2;06-5;0 years) as judged by their parents. Additionally, the influence of familiarity, gender and age of the child was determined. PATIENTS AND METHODS: Word, sentence and story productions of 163 healthy children (83 boys and 80 girls) between 2;06 and 5;0 years were transcribed by their own parents. Speech intelligibility was determined according to the intelligibility index described by Shriberg. Additionally, a panel of 12 unfamiliar judges listened to the recordings of a subgroup of 24 randomly selected children. RESULTS: Speech intelligibility improved with increasing age and was around 90% for children aged 4;6-5;0 years. Boys and girls performed equally on the task. For the intelligibility of words, mothers scored significantly better than unfamiliar listeners did. CONCLUSION: The reported normative speech intelligibility data provide important reference information for speech pathologists who assess child speech. Moreover, it enables them to measure the effect of a specific therapeutic approach and the spontaneous transfer to daily speech.

Interdependency between intensity and pitch in the normal speaking voice.

Intensity and pitch of the normal speaking voice are to some degree connected to each other. From a physiological point of view this interdependency can be explained by the fact that, to a certain extent, the same laryngeal and respiratory forces are involved in the regulation of both parameters. Measurements in 250 normal speakers show, on the average, a spontaneous pitch rise of about 9 semitones when the vocal intensity increases with 30 dB. The rise is non-linear and most pronounced on the highest intensities. A too high pitch, e.g., really more than 9 semitones for a vocal intensity increase of 30 dB, could represent a voice misuse.

Are voice endurance tests able to assess vocal fatigue?

Voice endurance tests are often used to evaluate vocal fatigue or to test the suitability of an individual for voice demands. It is assumed that these tests help to identify subjects with laryngeal or vocal fatigue out of a population of persons with complaints of discomfort in the throat, recurrent hoarseness and decreased voice power. In this study we evaluated the Voice Interval Test with respect to its discriminative power by comparison of voice performances in 20 patients with a history of vocal fatigue with that in 12 healthy subjects. Voice performance was studied during the Voice Interval Test as well as during regular use of the voice on a working day by electroglottography (EGG), acoustic analysis and a self-rating scale for pain and fatigue. Despite the number of tests the data did not reveal any significant difference between the patients and the healthy subjects. Voice fatigue could therefore not be identified and the clinical relevance of the Voice Interval Test appears to be questionable.

Vocal load as measured by the voice accumulator.

Voice disorders related to occupation and work environment are often observed in ENT consultations. Advising these patients requires not only the investigation of their vocal capacities but also knowledge about their vocal load. The patient will name extreme demands as the reason for vocal problems whereas the employer will want to know if the patient is capable of doing the work required of him. For an objective measurement of vocal load, a voice accumulator has been developed. This portable instrument records total speaking time and sound level over a period of several hours. The data can be transferred to a personal computer which analyses voiced time (s) between 60 and 112 dB(A)s. Thus, more precise and objective documentation of vocal demands in some professions can finally be obtained. With these results, it is possible to monitor vocal ability or disability during vocal rehabilitation.

Characterization of the electroglottographic waveform: a primary study to investigate vocal fold functioning.

To objectify the vocal fold functioning we opted for a method of processing the electroglottographic (EGG) signal. This study with 7 normal and 12 pathological voices presents the results of measurements over the chest register as a function of voice intensity and frequency. Reproduction measurements show that at least 5 measurements per intensity/frequency pair are needed to get a reasonable estimation of the EGG parameters. The averaged results over about 20 measurements in the chest register showed differences for some parameters for subjects in the most different categories. To get more consistent results we recommend to improve the measurement protocol and adjust the parameters.