Evaluating a computer system used as a microswitch for word utterances of persons with multiple disabilities

A systematic review and evaluation of procedures for the induction of speech among persons with developmental disabilities

OBJECTIVE

Deficits in vocal speech are common among those with developmental disabilities. This review examines interventions for teaching speech to individuals who presented as nonspeaking, or with low levels of vocalizations at baseline, and assesses evidence-based practice in this area.

METHODS

Systematic searches identified 78 studies suitable for inclusion. These studies were evaluated in terms of (a) participants, (b) intervention, (c) intervention setting, (d) intervention agent, (e) treatment efficacy, (f) generalization and maintenance of treatment effects, and (g) research rigor.

RESULTS

A variety of interventions, primarily behavioral, intended to induce vocal speech were delivered to participants with developmental disabilities aged between six months and 57 years. Treatment efficacy was variable (PND M = 52.9%; range 0%-100%); however, results indicated that behavioral interventions constituted evidence-based practice. Non-behavioral strategies were shown to have received insufficient research evaluation to date.

CONCLUSION

Results indicate that a number of procedures can induce speech among individuals with developmental disabilities.

Microswitch-Based Programs for Persons with Multiple Disabilities: An Overview of Some Recent Developments

Persons with multiple disabilities are often unable to interact with their environment due to their limited response repertoire. Microswitch programs are designed to help them control environmental events, generally preferred stimulation, through simple (feasible) responses. To make microswitch programs a more widely usable and relevant resource for intervention with these persons, a number of new developments were pursued in recent years. This paper examines three of those developments as specifically addressed in our research activity, namely, (a) assessment of new, nontypical responses and matching microswitches, (b) fostering of multiple responses and exercise of choice, and (c) targeting of habilitative and clinical (therapeutic) objectives. The encouraging outcomes of these developments are reviewed in relation to their potentially wide implications for daily practice and the need of additional developments in the area.

Enabling students with multiple disabilities to request and choose among environmental stimuli through microswitch and computer technology

This study assessed the possibility of enabling two students with multiple disabilities to request and choose among environmental stimuli through microswitch and computer technology. Each student was provided with two basic microswitches the activation of which made a computer system present a sample of a preferred or non-preferred stimulus. The student could select or reject such a stimulus by vocal utterances discriminated by the computer system as 'yes' or 'no'. If the student selected the stimulus, the computer system presented it for a preset time. If the student rejected the stimulus, the computer system waited for the next input of one of the basic microswitches. Data showed that both students learned to activate the basic microswitches consistently, selected the preferred stimuli about 90% of the times, and largely rejected the non-preferred stimuli. The students also showed some preferences between the two basic microswitches/responses. The performance was maintained at the post-intervention checks carried out 3 and 6 weeks after the end of the intervention. Implications of the findings are discussed technically, practically, and in terms of quality of life.

Extending the evaluation of a computer system used as a microswitch for word utterances of persons with multiple disabilities

BACKGROUND

Micro-switches can be vital tools to help individuals with extensive multiple disabilities acquire control of environmental stimulation. This study was aimed at extending the evaluation of a computer system used as a microswitch for word utterances with three participants with multiple disabilities.

METHOD

Sets of 7 or 12 word utterances were used for the participants. The utterances were divided into three groups, which were exposed to intervention successively. During the intervention and a 2-month post-intervention check, the participants' emission of the target utterances led the system to present favourite, matching stimuli (i.e. provided that it recognized the utterances).

RESULTS

Intervention data showed that (1) the participants increased the frequencies of the target utterances and (2) the computer system recognized approximately 80% of those utterances. These findings were maintained at the post-intervention check. An analysis of the levels of occurrence of individual utterances showed statistically significant differences among them, in line with the notions of preference and choice.

CONCLUSIONS

The computer system was useful as a microswitch to enable access to favourite stimuli. There is a need to improve the accuracy of the system with respect to its recognition of the participants' utterances.

Microswitch programs for persons with multiple disabilities: an overview of the responses adopted for microswitch activation

BACKGROUND

To introduce a person with multiple disabilities to a microswitch-aided program, one has to select a plausible response(s), that is, a response(s) that can be performed reliably and without excessive effort by the person and can successfully activate the microswitch(es) available (producing preferred stimuli). This paper provides an overview of the responses adopted for microswitch activation in research studies during the last 20 years.

METHOD

Computerized and manual searches were carried out to identify the studies published between 1986 and 2005. Forty-eight research studies were identified. They concerned the use of (1) a single (typical) response, (2) a single (non-typical) response, (3) multiple (typical and non-typical) responses, and (4) multiple (vocal) responses.

RESULTS AND DISCUSSION

The results showed that 151 of the 190 participants involved in the studies had a positive outcome (i.e., clear increases in their responding, which suggested that they had learned the association between responding and consequent preferred stimuli). Failures were largely concentrated in the first group of studies. The discussion focused on (a) the importance of selecting plausible responses for increasing the chances of success, (b) the need of non-typical responses for persons with minimal motor behavior, (c) implications of programs with multiple responses on engagement and choice, and (d) relevance of using vocal utterances. Some suggestions for future research concerning these points were also examined.