Theory of mind in children with autistic disorder: evidence of developmental progression and the role of verbal ability.

The present study investigated theory of mind in two groups of autistic children with markedly different verbal mental ages but comparable nonverbal ability and chronological ages, using a range of theory of mind belief tasks. The aims were to look for evidence of developmental progression of theory of mind ability in autistic children and to examine the role played by verbal ability in task performance. The results showed hierarchical patterns of performance across tasks, suggesting a developmental sequence of emerging aspects of theory of mind ability. There was clear evidence that verbal ability is an important contributor to successful task performance.

A response to "On token reinforcement and stuttering therapy: Another view on findings reported by Howie and Woods (1982)".

Ingham's (1983) critique of our research is based on the unwarranted assumption that it claimed to be a replication of Ingham and Andrews' (1973a) study. Our report did not claim to be a replication. Procedural differences between treatments do not preclude the possibility of drawing general conclusions that may apply to related treatments, or suggesting possible confounding variables that might be operating in another study. We have nevertheless dealt with each of Ingham's methodological objections. In general, we believe that we struck an acceptable compromise between the needs of clients and theoretical and research demands. We stand by our original conclusions, and note with satisfaction that Ingham concurs with our emphasis on systematic structure rather than the presence or absence of rewards as the crucial component of this type of stuttering treatment.

Relationship between covert and overt speech measures immediately before and immediately after stuttering treatment.

Overt and covert assessments of monologue and conversational speech were compared in 22 male adult stutterers immediately prior to the commencement of intensive treatment, and in 15 male adult stutterers immediately after completion of intensive treatment. There were no overall differences between covert and overt speech measures taken immediately before treatment. Immediately after intensive treatment, stuttering frequency (%SS) was significantly higher in covert evaluation than in overt evaluation, though the magnitude of the difference was small. There were no consistent covert-overt differences in speech rate (SPM). These results suggest that overt speech samples constitute a valid source of information about stutterers' 'real life' speech immediately before treatment but are less valid immediately after treatment.

Stuttering: speech pattern characteristics under fluency-inducing conditions.

Speech samples were collected from three adult male stutterers under six baseline conditions and 15 conditions believed to increase fluency. After moments of stuttering and filled pauses had been deleted from the samples, a speech pause analysis technique developed by Goldman-Eisler was used to measure the following speech pattern characteristics: mean phonation duration (i.e., the duration between pauses), pause proportion, articulation rate, fluent speech rate, mean sentence length, and percentage of syllables stuttered. Greater than 50% reduction in stuttering occurred in all but three conditions (Speak and Write, Relaxed, Alone with cards). Greater than 90% reduction occurred under Prolonged/DAF speech, Singing, Chorus reading, Shadowing, Slowing, Syllable-timed speech, and Response contingent stimulation. The data were examined for evidence of speech pattern characteristic changes which were associated with reduced stuttering. Lengthened mean phonation duration occurred consistently under four conditions: Chorus reading, Shadowing, Singing, and Prolonged/DAF. Slowed speech (lower overall rate, lower articulation rate, or increased pause proportion) occurred consistently in seven conditions: Prolonged/DAF, Slowing, Syllable-timed speech, Arm swing, Speak and write, Relaxed, and Singing. Only in Prolonged/DAF speech did lengthened phonation duration occur in conjunction with slowed speech. The results of this exploratory study suggest that stuttering may be reduced under different conditions by means of different strategies. Lengthened phonation and slowing were the predominant strategies used in those conditions investigated in this study. The results are consistent with those of effective treatment techniques. Theoretical accounts of the association between change in fluency and change speech pattern characteristics are discussed.

Locus of control and maintenance of behavioural therapy skills.

Thirty stutterers were treated in an intensive behavioural therapy programme in which speech and behavioural skills are taught. Treatment was shown to be effective in the long term in eliminating most stuttering behaviour. The effect of therapy on the stutterer's long-term perceptions of self-control was investigated. Those clients who attributed positive treatment effects to their own efforts or control also maintained their improvement in the behaviours acquired during therapy. Further planned research is needed to clarify whether attributions of self-control contribute to the client's ability to maintain therapy skills.

Token reinforcement during the instatement and shaping of fluency in the treatment of stuttering.

The value of token reinforcement in the instatement and shaping of fluency was examined in an intensive treatment program for adult stutterers. Experiment 1 examined the effect of removing the tangible back-up reinforcers for the token system and found that clients' performance in the program was equally good with or without these back-up reinforcers, suggesting that a strict token economy may not be crucial to rapid progress through treatment. Experiment 2 compared contingent and noncontingent taken reinforcement, while controlling for some variables that may have confounded the results of earlier research, and found no difference in clients' performance. Experiment 3 examined the effect of the entire removal of token reinforcement. Performance was found to be no worse under a "no tokens" system than under a system of tokens with back-up reinforcers. It is argued that in a highly structured treatment program where many other reinforcers are operating, token reinforcement may be largely redundant. Clinical and theoretical implications of the findings are discussed.

Concordance for stuttering in monozygotic and dizygotic twin pairs.

The role of genetic factors in the etiology of stuttering was investigated in 30 pairs of same-sex twins, each pair containing at least one stutterer. Care was taken to ensure maximum accuracy in zygosity classification and objectivity in stuttering diagnosis. Zygosity classification was made independently of stuttering diagnosis. Pair-wise concordance for stuttering was significantly higher in identical twins (63%) than in fraternal same-sex twins (19%). The estimated risk of stuttering in the monozygotic (MZ) co-twin of a stutterer was .77, and .32 in the dizygotic (DZ) co-twin of a stutterer. The findings strongly suggest the operation of genetic factors in stuttering. However, the presence of as many as six pairs of identical twins who were discordant for stuttering underlines the importance of the interaction of genetic and environmental factors in the etiology of this disorder.

Intrapair similarity in frequency of disfluency in monozygotic and dizygotic twin pairs containing stutterers.

It is known that concordance for stuttering is higher in monozygotic (MZ) than in dizygotic (DZ) twins. Evidence for genetic contribution to the frequency of speech disruption in stutterers was examined in 17 pairs of MZ and 13 pairs of DZ twins, each pair containing at least one stutterer. Intraclass correlations and analyses of variance indicated positive evidence for a genetic contribution to the overall frequency of disfluency in speech and to the frequency of certain types of speech disruption (blocked and prolonged sounds). There was little evidence for genetic influence on other types of speech disruption (various types of repetitions and interjections) In those disfluency types for which genetic predictions were confirmed, evidence of excessive dissimilarity in DZ cotwins suggests that a simple, additive gene-environment model is unlikely to be appropriate for disfluency frequency data.

Short- and long-term outcome in an intensive treatment program for adult stutterers.

A three week intensive treatment program for adult stutterers is described. This treatment has evolved from an original program developed by Ingham and Andrews (1973) using speech prolongation techniques, gradual shaping of speech rate to normal, and systematic transfer of skills acquired in the clinic to real life situations. Immediately after intensive treatment, stuttering was virtually eliminated and speech rate and attitudes toward communication were normalized. There was no substantial deterioration in these treatment effects when clients were evaluated in the clinic after two months in the Maintenance Phase of treatment. Speech and attitude measures collected outside the clinic 12--18 months after intensive treatment showed lasting overall improvement in most clients, although some deterioration in fluency from immediate post-intensive treatment levels had occurred in 40% of clients. Covertly collected data supported this finding. Possible causes of relapse and likely solutions are discussed.

Dysarthria of adult cerebral palsy: II. Phonemic analysis of articulation errors.

The articulation errors of 32 spastic and 18 athetoid males, aged 17-55 years, were analyzed using a confusion matrix paradigm. The subjects had a diagnosis of congenital cerebral palsy, and adequate intelligence, hearing, and ability to perform the speech task. Phonetic transcriptions were made of single-word utterances which contained 49 selected phonemes: 22 word-initial consonants, 18 word-final consonants and nine vowels. Errors of substitution, omission and distortion were categorized on confusion matrices such that patterns could be observed. It was found that within-manner errors (place or voicing errors or both) exceeded between-manner errors by a substantial amount, more so on final consonants. The predominant within-manner errors occurred on fricative phonemes for both initial and final positions. Affricate within-manner errors, all of devoicing, were also frequent in final position. The predominant between-manner initial position errors involved liquid-to-glide and affricate-to-stop changes, and for final position, affricate-to-fricative. Phoneme omission occurred three times more frequently on final than on initial consonants. The error data of individual subjects were found to correspond with the identified overall group patterns. Those with markedly reduced speech intelligibility demonstrated the same patterns of error as the overall group. The implications for treatment are discussed.