Microswitch for vocalization responses: comparing single- versus dual-microphone arrangements for a man with multiple disabilities

Microswitches are technical devices designed to enable persons with multiple disabilities to control environmental events, generally preferred stimuli such as music and lights, using simple/feasible responses. For example, a sound-detecting microswitch may allow a person to turn on brief periods of preferred stimulation through simple vocal responses. This study compared the accuracy of two versions of a sound-detecting microswitch, i.e., one using a throat microphone and the other both throat and airborne microphones, for a man with multiple disabilities. Analysis showed that the latter microswitch version radically reduced the false activations present with the former microswitch version. Thus, the latter version seemed to have a clear accuracy advantage over the former with important practical implications.     

Enabling persons with multiple disabilities to choose among environmental stimuli and request stimulus repetitions through microswitch and computer technology

This study assessed microswitch and computer technology to enable two participants with multiple disabilities, 32 and 19 years of age, to choose among environmental stimuli and request their repetition whenever they so desired. Within each session, 18 stimuli (12 preferred and 6 nonpreferred) were available. For each stimulus, a computer system provided a sample of 3 sec. duration. During the intervention, participants' vocal responding in relation to a stimulus sample activated a microswitch and a computer system turned on that stimulus for 15-30 sec. When participants did not vocally respond, the computer system paused briefly and then presented the next scheduled stimulus sample. When participants vocally responded at the end of a stimulus presentation, the stimulus was repeated. Intervention data showed that the participants learned to choose preferred stimuli and bypass nonpreferred ones as well as to request repetitions of the preferred stimuli. This performance was maintained at a 1-mo. postintervention check and transferred to sets of stimuli not used in the intervention. The implications of these results were discussed.     

Response Facilitation and Inhibition in Manual,Vocal, and Oculomotor Performance: Evidence for a Modality-Unspecific Mechanism

In 2 experiments (N = 10, Experiment 1; N = 16, Experiment 2), the authors investigated whether evidence for response facilitation and subsequent inhibition elicited by masked prime stimuli can be observed for output modalities other than manual responding. Masked primes were followed by target stimuli that required a 2-choice manual, saccadic, or vocal response. Performance was measured for compatible trials in which primes and targets were identical and for incompatible trials in which they were mapped to opposite responses. When primes were presented centrally, performance benefits were obtained for incompatible trials; whereas for peripherally presented primes, performance benefits were found in compatible trials. That pattern of results was obtained for manual responses and for saccadic eye movements (Experiment 1), demonstrating that those effects are not mediated by specialized dorsal pathways involved in visuomanual control. An analogous pattern of effects was found when manual and vocal responses were compared (Experiment 2). Because vocal responding is controlled by the inferotemporal cortex, that result shows that prime-target compatibility effects are not primarily mediated by the dorsal stream, but appear to reflect modality-unspecific visuomotor links that allow rapid activation of motor responses that may later be subject to inhibition.     

Technological aids to promote basic developmental achievements by children with multiple disabilities: evaluation of two cases

Technological aids such as microswitches may be critical to foster learning and development in children with multiple disabilities. In study I, a child with minimal motor behavior was provided with a microswitch for chin movements to assess whether he could learn to use these movements to activate environmental stimuli. In study II, a child with dystonic (difficult-to-control) behavior was provided with microswitches for two motor responses and two vocal utterances. We wanted to assess whether he could use both types of responses effectively (varying within each pair, consistent with choice performance). The results were highly encouraging with both children. In study I, there was a significant increase in the childs responding, suggesting learning and contingency awareness. In study II, there was a significant increase in responding as well as response variation that suggested choice behavior. The importance of microswitch devices in promoting new learning/developmental objectives and improving quality of life is discussed.     

Promoting adaptive foot movements and reducing hand mouthing and eye poking in a boy with multiple disabilities through microswitch technology

This study assessed the viability of a microswitch cluster (i.e. a combination of microswitches) plus contingent stimulation for promoting adaptive responding and reducing aberrant behavior in a boy with profound multiple disabilities. The boy was initially taught an adaptive foot-movement response that activated a motion microswitch and produced preferred stimuli. Subsequently, his foot response led to preferred stimuli only if it occurred in the absence of aberrant behavior (i.e. hand mouthing and eye poking which were detected through optic microswitches). Moreover, full access to the stimuli required that the boy refrain from aberrant behavior during their presentation as well. The study also included a 3-month post-intervention check and a social validation assessment. Data showed that the boy (i) increased his adaptive responding, (ii) learned to perform this responding largely free from aberrant behavior and refrained from that behavior for most of the session time, and (iii) maintained this performance at the post-intervention check. The social validation ratings of 40 teachers and teacher assistants significantly favored the last intervention period (in which aberrant behavior was reduced) over the initial period.     

A microswitch‐based program for promoting initial ambulation responses: An evaluation with two girls with multiple disabilities

We assessed the use of a microswitch‐based program for promoting ambulation responses by two children with multiple disabilities. The goals of the study were to: (a) evaluate the importance of the contingency between the target behavior (forward step) and the programmed consequence (preferred stimuli), (b) measure effects of the intervention on indices of happiness, and (c) assess the social validation of the procedure using 20 physiotherapists as external raters. The intervention involved the automatic delivery of preferred stimuli contingent on forward steps. Results showed that both participants improved their performance (forward steps and indices of happiness) during contingent reinforcement phases compared to baseline and noncontingent reinforcement phases. Moreover, physiotherapists rated the intervention as socially valid.     

Access to environmental stimulation via eyelid responses for persons with acquired brain injury and multiple disabilities: a new microswitch arrangement

This study assessed a new microswitch arrangement for eyelid responses using an optic sensor placed above the cheekbone and a small sticker on the person's eyelid. This new arrangement, which was designed to avoid interference of the microswitch with the person's visual functioning, was tested on three adults with acquired brain injury and multiple (consciousness, communication, and motor) disabilities. The study was carried out according to a non-concurrent multiple baseline design across participants. Data showed the new microswitch arrangement was suitable for all three participants, who increased their responding during the intervention phase of the study when their responses allowed them to access preferred stimulation. Practical implications of the findings are discussed.     

Operant and nonoperant vocal responding in the mynah: Complex schedule control and deprivation-induced responding

Several recent studies have been concerned with operant responses that are also affected by nonoperant factors, (e.g., biological constraints, innate behavior patterns, respondent processes). The major reason for studying mynah vocal responding concerned the special relation of avian vocalizations to nonoperant emotional and reflexive systems. The research strategy was to evaluate operant and nonoperant control by comparing the schedule control obtained with the vocal response to that characteristic of the motor responses of other animals. We selected single, multiple, and chain schedules that ordinarily produce disparate response rates at predictable times. In multiple schedules with one component where vocal responding (“Awk”) was reinforced with food (fixed-ratio or fixed-interval schedule) and one where the absence of vocal responding was reinforced (differential reinforcement of other behavior), response rates never exceeded 15 responses per minute, but clear schedule differences developed in response rate and pause time. Nonoperant vocal responding was evident when responding endured across 50 extinction sessions at 25% to 40% of the rate during reinforcement. The “enduring extinction responding” was largely deprivation induced, because the operant-level of naive mynahs under food deprivation was comparable in magnitude, but without deprivation the operant level was much lower. Food deprivation can induce vocal responding, but the relatively precise schedule control indicated that operant contingencies predominate when they are introduced.     

The operant control of vocalization in the dog

Control over the vocal responses of three dogs was established using operant-conditioning procedures. Several points of interest were observed in the data. First, fixed-ratio schedules of reinforcement generated a vocal response topography which was similar in detail to that of a “motor” bar-nosing response. Second, vocal responding was brought under the control of external visual stimuli as a result of differential reinforcement. Third, good stimulus control was maintained on a multiple schedule containing a vocal-response component and a bar-response component. Fourth, the stimulus control on the multiple schedule transferred with minimal disruption to a chain schedule requiring a sequence of 10 bar responses followed by 10 vocal responses. Fifth, because vocal and bar responses are not mutually exclusive, concurrent responding tended to develop on the chain schedule.

These results were discussed with reference to the advisability of applying the terms operant and respondent to unconditioned behavior, and, particularly, to unconditioned verbal behavior.

     

TEACHING CHOICE MAKING DURING SOCIAL INTERACTIONS TO STUDENTS WITH PROFOUND MULTIPLE DISABILITIES

We taught 4 students with profound multiple disabilities to use a microswitch communication system to request a change in recreational stimuli during social interactions with nondisabled peers. In Study 1, we conducted a preference assessment across a range of stimuli for each student. The most and least preferred stimuli were incorporated into microswitch communication system training in Study 2. During the second study, 3 of the 4 students (a) learned to use the microswitch communication system to control stimulus presentation, (b) more clearly differentiated their time among stimuli, and (c) increased their level of general alertness. Study 3 extended the use of the microswitch communication system to social interactions with nondisabled peers. Two students were more engaged in interactions when they chose when to change stimuli; 1 student was more alert when a peer chose when to change activities; a 4th student showed an undifferentiated pattern. The outcomes of the investigation are discussed in terms of the effects of controlling stimulus presentation on the behavior of students with profound multiple disabilities and the stability of preference hierarchies over time.     

Response facilitation and inhibition in manual, vocal, and oculomotor performance: evidence for a modality-unspecific mechanism

In 2 experiments (N = 10, Experiment 1; N = 16, Experiment 2), the authors investigated whether evidence for response facilitation and subsequent inhibition elicited by masked prime stimuli can be observed for output modalities other than manual responding. Masked primes were followed by target stimuli that required a 2-choice manual, saccadic, or vocal response. Performance was measured for compatible trials in which primes and targets were identical and for incompatible trials in which they were mapped to opposite responses. When primes were presented centrally, performance benefits were obtained for incompatible trials; whereas for peripherally presented primes, performance benefits were found in compatible trials. That pattern of results was obtained for manual responses and for saccadic eye movements (Experiment 1), demonstrating that those effects are not mediated by specialized dorsal pathways involved in visuomanual control. An analogous pattern of effects was found when manual and vocal responses were compared (Experiment 2). Because vocal responding is controlled by the inferotemporal cortex, that result shows that prime-target compatibility effects are not primarily mediated by the dorsal stream, but appear to reflect modality-unspecific visuomotor links that allow rapid activation of motor responses that may later be subject to inhibition.     

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.     

Camera-Based Microswitch Technology to Monitor Mouth,Eyebrow, and Eyelid Responses of Children with Profound Multiple Disabilities

A camera-based microswitch technology was recently used to successfully monitor small eyelid and mouth responses of two adults with profound multiple disabilities (Lancioni et al., Res Dev Disab 31:1509–1514, 2010a). This technology, in contrast with the traditional optic microswitches used for those responses, did not require support frames on the participants’ face but only small color marks. The present study was aimed at extending the research evidence available on the aforementioned technology with the involvement of new participants and responses. The participants were three children with profound multiple disabilities. The responses selected for them consisted of mouth closing, eyebrow lifting, and repeated eyelid closures. The results showed that the new technology could be satisfactorily applied with all three children, across the three different responses. All children had large increases in responding during the intervention periods (i.e., when their responses were followed by preferred stimulation). The findings are discussed in relation to the possible impact of the new technology on programs for persons with multiple disabilities and minimal motor behavior.     

A response-spacing effect: an absence of responding during response-feedback stimuli

In most studies of operant reinforcement a response-feedback stimulus is used which is so brief that the nature of the responding during it is virtually undetectable. The present study investigated the nature of this responding by lengthening an initially brief feedback stimulus. The key-pecking responses of pigeons were maintained by a variable-interval schedule of food reinforcement. Each response produced a brief stimulus light in addition to the usual auditory response feedback. When the duration of the feedback stimulus light was gradually increased, it was found to control a nearly zero rate of responding. The result was a paced, metronomic-like performance in which the pigeon made a single response, paused until the stimulus terminated, and then responded again. As a result, the overall response rate was greatly reduced; the mean interresponse time approximated the stimulus duration. A plausible interpretation is that brief feedback stimuli acquire control over responding because they coincide with few responses and few reinforcers. These findings show that in addition to their known functions as conditioned-reinforcing stimuli and discriminative stimuli, response-feedback stimuli also exert direct stimulus control: responding is reduced during the feedback stimulus itself.     

EFFECTS OF PREFERENCE AND REINFORCER VARIATION ON WITHIN-SESSION PATTERNS OF RESPONDING

We examined correspondence between preference assessment outcome and within‐session patterns of responding in one subject with autism. Responding maintained by a single highly preferred item resulted in a greater total number of responses, a slower decline in within‐session response rates, and a greater proportion of short interresponse times compared to responding maintained by varied moderately preferred (MP) stimuli. Presenting varied MP stimuli within the same session produced greater levels and more sustained responding than presenting those same stimuli individually.     

Enabling a man with multiple disabilities and limited motor behavior to perform a functional task with help of microswitch technology

This study evaluated the extent to which two microswitches used as interfaces would enable a man with multiple disabilities and limited motor behavior to operate an electric door opener at the entrance of the day center that he attended. Analysis showed the man (a) learned to use the two microswitches, (b) preferred the microswitch placed at his wheelchair's footrest (which also allowed more effective responding) over the microswitch placed at his wheelchair's armrest, and (c) maintained his positive performance at the 1- and 2-mo. postintervention checks. The results were discussed from a technical and practical standpoint and in terms of implications for the quality of life of persons with disabilities.     

Bad–good constraints on a polarity correspondence account for the spatial–numerical association of response codes (SNARC) and markedness association of response codes (MARC) effects

Performance in numerical classification tasks involving either parity or magnitude judgements is quicker when small numbers are mapped onto a left-sided response and large numbers onto a right-sided response than for the opposite mapping (i.e., the spatial–numerical association of response codes or SNARC effect). Recent research by Gevers et al. [Gevers, W., Santens, S., Dhooge, E., Chen, Q., Van den Bossche, L., Fias, W., & Verguts, T. (2010). Verbal-spatial and visuospatial coding of number–space interactions. Journal of Experimental Psychology: General, 139, 180–190] suggests that this effect also arises for vocal “left” and “right” responding, indicating that verbal–spatial coding has a role to play in determining it. Another presumably verbal-based, spatial–numerical mapping phenomenon is the linguistic markedness association of response codes (MARC) effect whereby responding in parity tasks is quicker when odd numbers are mapped onto left-sided responses and even numbers onto right-sided responses. A recent account of both the SNARC and MARC effects is based on the polarity correspondence principle [Proctor, R. W., & Cho, Y. S. (2006). Polarity correspondence: A general principle for performance of speeded binary classification tasks. Psychological Bulletin, 132, 416–442]. This account assumes that stimulus and response alternatives are coded along any number of dimensions in terms of – and + polarities with quicker responding when the polarity codes for the stimulus and the response correspond. In the present study, even–odd parity judgements were made using either “left” and “right” or “bad” and “good” vocal responses. Results indicated that a SNARC effect was indeed present for the former type of vocal responding, providing further evidence for the sufficiency of the verbal–spatial coding account for this effect. However, the decided lack of an analogous SNARC-like effect in the results for the latter type of vocal responding provides an important constraint on the presumed generality of the polarity correspondence account. On the other hand, the presence of robust MARC effects for “bad” and “good” but not “left” and “right” vocal responses is consistent with the view that such effects are due to conceptual associations between semantic codes for odd–even and bad–good (but not necessarily left–right).     

Persons with acquired brain injury and multiple disabilities access stimulation independently through microswitch-based technology

The possibility of enabling two adults with acquired brain injury and profound multiple disabilities to use microswitch-based technology to attain preferred environmental stimuli on their own was assessed. Each of the participants was provided with two microswitches that could be activated by right and left head-turning or head-bending responses. The microswitches were introduced sequentially according to a multiple probe design across microswitches (responses) and allowed access to different sets of auditory or visual stimuli. Eventually, the two microswitches were made available simultaneously. Sessions lasted 5 min. Each participant learned to use the two microswitches successfully and maintained consistent levels of responding when they were simultaneously available. During this phase, both participants showed large within-session variations in their right and left response frequencies, with one of them showing an overall prevalence of the left-side response. The importance of assistive technology within programs for persons with acquired brain injury and multiple disabilities is discussed.     

Enabling two adolescents with multiple disabilities to choose among environmental stimuli through different procedural and technological approaches

Two single-case studies were carried out using different procedural and technological approaches to enable two adolescents with multiple disabilities to choose among environmental stimuli. Study I focused on replicating a recently developed procedure, which relied on samples of the auditory stimuli available as cues for choice responses. Study II assessed a new procedural and technical setup relying on the use of pictorial representations of the stimuli available as cues for choice responses. The auditory samples and the pictorial representations were presented through computer systems. The participants' choice responses relied on microswitches connected to the computer systems. The data of Study I fully supported previous findings with the same procedural approach. The participant learned to choose preferred stimuli and bypass nonpreferred ones. The data of Study II showed that the participant learned to concentrate his choice. responses on a few stimuli, suggesting that these stimuli were actually preferred and that responding was purposeful. Implications of the results were discussed.     

Teaching 'Yes' and 'No' responses to children with multiple disabilities through a program including microswitches linked to a vocal output device

The present study introduced two children (a boy and a girl of 9.2 and 12.3 yr. of age, respectively, with multiple disabilities) to an intervention program for establishing Yes and No responses in relation to preferred and nonpreferred stimuli and assessed the acquisition and generalization of those responses. The program involved the use of microswitches, which monitored the nonverbal Yes and No responses performed by the children and ensured that these responses produced the matching verbal utterances via a vocal output device. Analysis showed children acquired Yes and No responses in relation to the stimuli used for the intervention and, to a comparable degree, to the stimuli used for generalization checks as well. An interview of 30 educational staff of a center for persons with multiple disabilities indicated that they considered the presence of Yes and No verbal utterances preferable to the absence of such utterances, and thought that the utterances could be helpful for the children's response acquisition and would be useful and pleasing for staff and parents. General implications of the findings were discussed.