Assessment and Treatment of Selective Mutism

Abstract

We present the results of a stimulus fading procedure used to treat a six-year-old girl who met DSM-DJ-R criteria for elective mutism (now Selective Mutism in DSM-IV). An assessment protocol is presented that features procedures that can be used to render a diagnosis and assist in treatment planning. A treatment program was implemented through a consultation process that required close monitoring and revision over several months. Results of the case study suggested that the stimulus fading of new persons into the school setting was effective in producing speech. Future re-search directions in assessment and treatment of selective mutism are discussed.     

Developing auditory stimulus control: A note on methodology

This paper concerns the problem of teaching people with intellectual handicaps to respond reliably to spoken words and other auditory instructional stimuli. We describe how microcomputer technology can be applied to implement effective auditory stimulus control shaping methods. With hardware and software currently available, it is now possible to adapt procedures that have been previously successful in stimulus control programming with visual stimuli. We describe several techniques for programming gradual stimulus changes (e.g., stimulus fading, stimulus shaping) to promote auditory discrimination learning. Teaching studies with two individuals with severe mental retardation provide illustrative applications and data supporting the feasibility and potential utility of auditory stimulus control shaping methodology.     

The effects of noncontingent delivery of high- and low-preference stimuli on attention-maintained destructive behavior

An adolescent with severe mental retardation and cerebral palsy who displayed attention-maintained destructive behavior was exposed to noncontingent reinforcer delivery (NCR) with either a high-preference or a low-preference stimulus while reinforcement for destructive behavior with attention remained in effect (i.e., NCR without extinction). NCR without extinction was effective only when the high-preference stimulus was available, suggesting that systematic assessment of stimulus quality may enhance the effectiveness of NCR with alternative stimuli.     

Stimulus fading in the treatment of adipsia

Stimulus fading procedures have repeatedly been demonstrated as effective in shaping a wide variety of new behaviors. Borrowing from this body of research, the behavioral treatment of feeding disorders presents a new area of application for stimulus fading. The purpose of this study is to demonstrate the efficacy of stimulus fading in the treatment of adipsia. Two children who ate solids, but refused all liquids, were participants in the study. Results showed that a five step fading procedure starting with a spoon and thickened liquids, and ending with a cut‐out‐cup, was successful in establishing cup drinking skills for both children. Results of the study suggest that stimulus fading can facilitate feeding skill acquisition. Copyright © 2001 John Wiley & Sons, Ltd.     

Two sets of twins with selective mutism: neuropsychological findings.

Neuropsychological data are reviewed from two sets of dizygotic twins presenting with selective mutism characterized by situation specific anxiety, extreme passive behavior, lack of responsivity, lack of peer interaction, and a chronic course of selective mutism. Both sets of twins had a history of prematurity and delayed speech development. One set of twins presented with normal intelligence and normal receptive language skills but with expressive language and oral motor sequencing difficulties. The second set of twins presented with Verbal IQ deficits and significant receptive and expressive language deficits. A summary of current conceptualizations regarding etiology and treatment of selective mutism is provided.     

AN EVALUATION OF TWO METHODS FOR INCREASING SELF-INITIATED VERBALIZATIONS IN AUTISTIC CHILDREN

Three children with autism and mental retardation were treated for deficits in self-initiated speech. A novel treatment package employing visual cue fading was compared with a graduated time-delay procedure previously shown to be effective for increasing self-initiated language. Both treatments included training multiple self-initiated verbalizations using multiple therapists and settings. Both treatments were efffective, with no differences in measures of acquisition of target phrases, maintenance of behavioral gains, acquisition with additional therapists and settings, and social validity.     

Conditional discrimination after errorless and trial-and-error training.

Children were trained on a visual discrimination by stimulus shaping, stimulus fading, or trial-and-error. Those who did not acquire the conditional discrimination received a second, different training. More children initially trained by stimulus shaping acquired the conditional discrimination than did those initially trained with stimulus fading or trial-and-error. After a history of fading or trial-and-error training, children were less likely to acquire the conditional discrimination even after the more successful procedure of shaping was later used.     

SCHEDULE EFFECTS OF NONCONTINGENT REINFORCEMENT ON ATTENTION-MAINTAINED DESTRUCTIVE BEHAVIOR IN IDENTICAL QUADRUPLETS

Noncontingent reinforcement (NCR), a response-independent schedule for the delivery of reinforcement, has been found to be effective in reducing behavior when the reinforcer delivered is responsible for behavioral maintenance. In this study, dense and lean schedules of response-independent attention were compared to determine whether it is necessary to begin with a dense schedule before fading to a lean schedule, or whether treatment would be as effective using a lean schedule at the outset. The subjects were 5-year-old identical quadruplets diagnosed with mental retardation and pervasive developmental disorder who displayed destructive behavior that was maintained by social attention. NCR was selected partially because it is not very labor intensive and could be implemented by a single mother simultaneously with all 4 children. Using a combination multielement and multiple baseline design, it was found that (a) a dense schedule of response-independent reinforcement (i.e., fixed-time 10 s) resulted in immediate and dramatic reductions in destructive behavior with no evidence of an extinction burst, and (b) an equivalent reduction in destructive behavior was achieved with a lean schedule of response-independent reinforcement (fixed-time 5 min) only after a systematic fading procedure was implemented. The findings suggest that the effectiveness of NCR may be dependent on the use of a dense schedule initially, and that systematic fading can increase the effectiveness of a lean schedule.     

STIMULUS FADING AND TRANSFER IN THE TREATMENT OF SELF-RESTRAINT AND SELF-INJURIOUS BEHAVIOR

We conducted several manipulations of mechanical restraint properties during the course of treatment for two profoundly retarded adolescents who exhibited both self-restraint and self-injurious behavior. In study 1, a combination of prompting, differential reinforcement, and stimulus fading reduced one subject's self-restraint, which consisted of holding rigid tubes on his arms. Subsequently, stimulus control of both self-restraint and self-injurious behavior was transferred to tennis wrist bands. In study 2, a second subject's self-restraint—placing his hands in his pants—was immediately eliminated by the use of air splints. Additionally, differential reinforcement and air-pressure fading resulted in the complete mobility of his arms and a substantial increase in appropriate behaviors. Results of this investigation suggest that stimulus fading and transfer may be valuable components in the elimination of self-restraint.     

Relative and Absolute Judgments of Speech Rate from Masked and Content-Standard Stimuli The Influence of Vocal Frequency and Intensity

In two previous studies, the perception of speech rate was found to be positively related to the vocal frequency and intensity of speech. In those studies, a single sample of spontaneous, content-masked speech was used to produce nine stimuli by factorially varying three levels of each vocal frequency and intensity, while controlling the actual speech rate of the stimuli. Participants were asked to judge each stimulus, preceded by a standard, “anchoring,” stimulus as to its speech rate, pitch, loudness, and duration. The purpose of the three studies reported here was to examine the generalizability of the previous findings by using stimuli that were nonmasked and/or were not preceded by an anchoring stimulus. In each study, nine speech stimuli were prepared, as described above, and participants were asked to make judgments about the rate, pitch, loudness, and duration of each stimulus. In the first study, the stimuli were masked but were not preceded by an anchoring stimulus. In the second study, participants listened to content-standard speech stimuli preceded by an anchoring stimulus. Finally, in the third study, content-standard stimuli without an anchoring stimulus were used. In addition, studies two and three used speech segments of a male and a female speaker. The findings from the three studies replicated the central findings of the previous studies. They suggest, in other words, that rate perception of speech is indeed influenced by vocal frequency and, to some extent, by intensity, and that these relationships are not materially altered by the speakers'gender.     

The effects of response interruption,DRO and positive reinforcement on the reduction of hand-mouth behavior

The present study was designed to determine the effects of response interruption and differential reinforcement of other behavior (DRO) on the reduction of hand-mouthing behavior in a quadriparesic adult male client who functions at the profound level of mental retardation. In order to determine the effectiveness of the treatment package, a withdrawal design was used in which baseline (A) and treatment (B) conditions were alternated in an ABAB sequence. The treatment phase consisted of two 10 min treatment periods per day for four consecutive days. Two treatment/withdrawal rotations were followed by nine follow-up observation periods. A preliminary fading process was started following the follow-up periods, which included removal of the reinforcer. Hand-mouthing was reduced by 80% through the use of response interruption and DRO. Hand-mouthing continued to decrease during the nine follow-up observation periods and formal fading procedure. Implications for the extended use of such nonaversive procedures to decrease hand-mouthing behavior in persons with developmental disabilities are discussed. © 1997 John Wiley & Sons, Ltd.     

Speech perception deficits by Chinese children with phonological dyslexia

Findings concerning the relation between dyslexia and speech perception deficits are inconsistent in the literature. This study examined the relation in Chinese children using a more homogeneous sample—children with phonological dyslexia. Two experimental tasks were administered to a group of Chinese children with phonological dyslexia, a group of age-matched control children, and a group of adults. In addition to a categorical perception task, a selective adaptation task was carried out. The results indicated that Chinese children with phonological dyslexia were less consistent than both the child and adult control groups in identifying stimuli within a given phonetic category. Furthermore, they did not show any significant adaptation effects in the selective adaptation task even when the adapting stimulus was identical to an endpoint stimulus in the test continuum. It seems that children with phonological dyslexia have a general deficiency in representing and processing speech stimuli.     

Assessing control by elements of complex stimuli in delayed matching to sample.

A series of six experiments examined delayed identity matching-to-sample performances of subjects with mental retardation. The stimuli were either one or two simultaneously displayed forms. When the reinforcement contingencies required that only one form exert discriminative control, all subjects achieved high accuracy scores. However, accuracy scores were substantially lower when the contingencies required discriminative control by two forms, suggesting restricted stimulus control. The decline in matching accuracy appeared to reflect selective losses of conditional control by sample stimuli and shifts in control to features of the comparison stimulus displays. The experiments suggest improved techniques for assessing control by complex stimuli and for evaluating the effects of procedures that seek to broaden restricted stimulus control. The results challenge interpretations based on stimulus-generalization decrement or shared attention.     

Stimulus fading and differential reinforcement for the treatment of needle phobia in a youth with autism

Stimulus fading in the form of gradually increased exposure to a fear-evoking stimulus, often combined with differential reinforcement, has been used to treat phobias in children who are otherwise normal and in children with autism. In this investigation, we applied stimulus fading plus differential reinforcement with an adolescent with autism and diabetes whose needle phobia had prevented medical monitoring of his blood glucose levels for over 2 years. Results showed that the treatment was successful in obtaining daily blood samples for measuring glucose levels.     

Role of cerebellum in fine speech control in childhood: persistent dysarthria after surgical treatment for posterior fossa tumour

Dysarthria following surgical resection of childhood posterior fossa tumour (PFT) is most commonly documented in a select group of participants with mutism in the acute recovery phase, thus limiting knowledge of post-operative prognosis for this population of children as a whole. Here we report on the speech characteristics of 13 cases seen long-term after surgical treatment for childhood PFT, unselected for the presence of post-operative mutism (mean time post-surgery = 6y10 m, range 1;4-12;6 years, two had post-operative mutism), and examine factors affecting outcome. Twenty-six age- and sex- matched healthy controls were recruited for comparison. Participants in both groups had speech assessments using detailed perceptual and acoustic methods. Over two-thirds of the group (69%) with removal of PFT had a profile of typically mild dysarthria. Prominent speech deficits included consonant imprecision, reduced rate, monopitch and monoloudness. We conclude that speech deficits may persist even up to 10 years post-surgery in participants who have not shown mutism in the acute phase. Of cases with unilateral lesions, poorer outcomes were associated with right cerebellar tumours compared to left, consistent with the notion based on adult data that speech is controlled by reciprocal right cerebellar/left frontal interactions. These results confirm the important role of the cerebellum in the control of fine speech movements in children.     

NONCONTINGENT PRESENTATION OF ATTENTION AND ALTERNATIVE STIMULI IN THE TREATMENT OF ATTENTION-MAINTAINED DESTRUCTIVE BEHAVIOR

Previous research has demonstrated that destructive behavior may be reduced through noncontingent presentation of attention when attention is identified as the stimulus responsible for behavioral maintenance. Because it may not always be possible to deliver attention in all situations, we examined the extent to which alternative stimuli that have been identified through a choice assessment would substitute for attention (the functional analysis—based reinforcer) in a noncontingent reinforcement procedure. Prior to treatment, functional analyses demonstrated that the destructive behavior of 2 clients with mental retardation was maintained by adult attention. Next, a stimulus choice assessment identified highly preferred tangible items for the 2 clients. Finally, we compared the effectiveness of two noncontingent reinforcement procedures: continuous noncontingent access to attention and continuous noncontingent access to the tangible item identified in the choice assessment. For both clients, these noncontingent reinforcement procedures reduced destructive behavior. The results are discussed in terms of the clinical implications for the treatment of destructive behavior using functional and alternative stimuli.     

Functional analysis and treatment of verbal perseverations displayed by an adult with autism

The function of perseverative speech for an adult man who had been diagnosed with autism and mental retardation was examined. Results showed that verbal perseverations were maintained by social attention. An intervention consisting of differential reinforcement of appropriate verbal responses and extinction of perseverative verbal responding was effective in decreasing verbal perseverations.     

Observed increases in positive affect during behavioral treatment

A 15‐year‐old female diagnosed with mental retardation was admitted to an inpatient facility for the assessment and treatment of a severe behavior disorder. A behavioral treatment to reduce destructive behavior consisting of enriched environment, differential reinforcement, and time‐out was evaluated in a reversal design. Data on affect were collected during baseline and treatment phases. In addition to achieving clinically significant reductions in problem behavior, collateral improvements in positive affect were observed during treatment phases. Copyright © 2003 John Wiley & Sons, Ltd.