Timing and intensity variability in the metronomic speech of stuttering and nonstuttering speakers.

The timing and intensity variability of 8 adults who stutter and 8 age-matched fluent speakers was investigated under metronomic conditions. Participants were required to produce double or triple-stress patterns at a slow speech rate (1 syllable/870 ms) when repeating the syllable /staet/or/straet/nine times. Measures that are sensitive to cyclic rather than overall variation in syllable timing and intensity were employed. Specifically, durational variation between successive syllable onsets as well as intensity variation of the beginning consonant and vowel in successive syllables were computed. Results revealed that, although intensity variation was similar, the timing of successive syllables of persons who stutter was significantly more variable than that of persons who do not stutter. These outcomes are discussed in relation to previous experiments of timing control of persons who stutter and normally fluent persons during metronomic stimulation.

Communicative styles of mothers interacting with their preschool-age children: a factor analytic study.

The aim of this study was to determine if mothers display identifiably different communicative styles in their interaction with their normally developing two- to five-year-old children. In order to investigate this issue an extensive coding system was developed, which assessed the structural organization and the communicative function of the speech of 71 mothers as they interacted with their children. By means of factor analysis three maternal communicative styles were distinguished: non-intervening, explaining and directing. In the non-intervening style there is no direct pressure from the mother on the child to respond verbally. The explaining mother is primarily concerned with providing information to her child in a way that gives the child little opportunity to take the speaking turn. The directing mother is mainly engaged in directing the child's behaviour by means of verbal control. The internal consistency of the three communicative styles appeared to be both satisfactory and related to relevant child and mother features.

Speech-associated attitudes of stuttering and nonstuttering children.

A Dutch version of the Communication Attitude Test (Brutten, 1985) was used to assess the speech-associated attitudes of 70 stuttering and 271 nonstuttering Belgian children of elementary and middle school age. The results showed that the stuttering children evidenced significantly more negative attitudes toward speech than did their nonstuttering peers. This difference was present from age 7, the youngest age group studied, on up. Moreover, a significant group x age interaction revealed that the speech-related attitudes of the stuttering children became more negative with increasing age. In contrast, those of the nonstuttering children became less negative after age 9. These findings suggest that, in the course of fluency therapy for youngsters who stutter, negative attitudes toward speech should be addressed. This is especially true if, as with adults who stutter, negative attitudes are predictive of therapeutic failure.

Speech-related reaction times of stutterers and nonstutterers: diagnostic implications.

Speech-related reaction time measures (laryngeal premotor and adjustment time for /a/, labial initiation and physiological voice onset time for /pa/) and fluency-related measures (number of stutterings, number of normal disfluencies, and time needed to complete an oral reading) of 24 stutterers and a like number of nonstutterers were assessed to determine their diagnostic discriminative power. Discriminant analysis showed that stutterers were most effectively differentiated from normally fluent speakers by the total number of stutterings and normal disfluencies during oral reading and by the duration of laryngeal adjustments prior to cued phonation. Factor analysis revealed that the fluency failure and reaction time measures clustered independently for both stutterers and nonstutterers. These findings suggest that both fluency failures and the duration of laryngeal adjustment time are useful diagnostic measures for discriminating stutterers from those who are normally fluent.

A comparative investigation of the laryngeal premotor, adjustment, and reaction times of stutterers and nonstutterers.

The laryngeal premotor, adjustment, and reaction times of 24 stutterers and 24 nonstutterers were assessed by means of a group (2) by stimulus modality (3) by stimulus order (6) factorial investigation. The laryngeal measures were determined from print outs made from electroglottographic recordings taken during the production of [a] that was cued by a visual, auditory, or somato-sensory stimulus. The results revealed that the laryngeal reaction times of stutterers were significantly longer than those of the nonstutterers. Moreover, the reaction times were significantly longer both during the laryngeal premotor and adjustment time periods. The observed between-group difference for each of these laryngeal measures was independent of the stimulus that was employed.

Eye movements of stuttering and nonstuttering children during silent reading.

During the silent reading of a 320-word passage, the eye movements of 22 grade school stutterers and 22 nonstutterers were recorded by means of a computer-controlled eye-marker. The recordings were made as a means of determining if the eye movements of the two groups differed and if the differences suggested that the young stutterers showed evidence of word-specific expectancy. Frame-by-frame analysis of the recordings revealed that the stuttering children displayed significantly more eye fixations and eye regressions than the nonstuttering children. The correlations among the different types of eye measures also varied between the subject groups. The differences observed were present despite the fact that the reading level of the two groups was age appropriate and the subjects sampled did not differ significantly in either reading errors or comprehension. These findings are like those previously found when stuttering and nonstuttering adults were similarly tested. They imply that expectancy is not the response province of older stutterers.

Expectancy and heart rate as predictors of the speech performance of stutterers.

Three adult stutterers who displayed a preexperimental pattern of consistent expectation and occurrence of stuttering were studied in a single-subject design. Multiple linear regression analyses led to the conclusion that cognitive (signalled) expectancy was predictive of stuttering for two of the subjects. The third subject evidenced essentially no relationship between signalled expectancy and disfluent performance. For two subjects, neither mean heart rate nor heart rate variability was predictive of speech performance. For the third subject, mean heart rate was predictive but heart rate variability was not. For two subjects, there was essentially no relationship between the measured physiologic variables and cognitive expectancy. However, for the third subject both mean heart rate and heart rate variability were significantly predictive of cognitive expectancy. These results suggest that adult stutterers should not be viewed as a homogeneous group with respect to preutterance activity that is either cognitive or physiologic. The relationship between preutterance heart rate, heart rate variability, and expectancy responses and between these preutterance variables and subsequent stuttering appears to be individualistic.

An eye-marking investigation of anticipated and observed stuttering.

The subjects of this experiment read a list of words and underlined those on which they expected speech difficulty. The matched and non-stutterers were subsequently called upon to read silently a connected passage in which half of these words were present. During this reading, the relation of eye movement to the words read was recorded on film. Frame by frame analysis of the eyes' exact momentary position revealed that the stutterers evidenced significantly more fixations than did the non-stutterers. They also showed significantly more progressive and regressive eye movements. It follows that the overall duration of their eye movements was somewhat shorter. In contrast, the average duration of the stutterers' fixations were significantly longer for those words on which fluency failure had been anticipated and on words on which it was later observed than on those words on which difficulty was not expected and those on which stuttering did not occur. These data suggest that stutterers search among the words to be spoken and sort out those on which they anticipate and on which they have difficulty.