Using functional behavioral assessment to treat sleep problems in two children with autism and vocal stereotypy

Abstract

Objectives: Sleep problems are prevalent among children with autism spectrum disorder (ASD) and are often accompanied by stereotypies, the function of which may be difficult to determine. Functional behavioral assessment (FBA) is an evidence-based approach to assessing and treating challenging behaviors, however, it has scarcely been used with sleep problems. This study investigates the effectiveness of FBA-based treatments for sleep disturbance (SD) in children with ASD, the short- and long-term maintenance of these effects, and parents’ perspectives on the assessment and treatment process.

Method: Two case studies used FBA to inform treatments for SD in two children with ASD and stereotypic behavior. The sleep-competing behaviors appeared to be multi-functional and included sleep interfering vocal stereotypy. The parents of each child implemented individualized, multi-component treatment packages.

Results: Results demonstrate a reduction in SD for each participant, though delayed sleep onset latency remained for one participant. These results were maintained at short- and long-term follow-up. The interventions had high social validity.

Conclusion: The implications of these findings for future research, and the assessment and treatment of SD in children with ASD and vocal stereotypy are discussed.

Sleep disturbance is one of the most common co-occurring clinical issues in children with ASD, being present in 33–80% of such children (Goldman et al. 2011, Rzepecka et al. 2011, Park et al. 2012, Mannion et al. 2013). Sleep disturbance may include delayed sleep onset latency (SOL), frequent and prolonged night-wakings (NWs) and early morning wakings (Cotton and Richdale 2006, Cortesi et al. 2010). Sleep disruption has negative concomitant effects on children’s daytime functioning, family functioning, and parental well-being (Schreck et al. 2004, Chu and Richdale 2009, Cortesi et al. 2010, Taylor et al. 2012, Hodge et al. 2013), and when untreated, is likely to persist (Wiggs and Stores 2007, Hodge et al. 2014).

Sleep disturbance in children with ASD is likely to be the result of a complex interaction between medical, neurodevelopmental, behavioral, psychosocial, biological and environmental variables (Krakowiak et al. 2008, Richdale and Schreck 2009, Goldman et al. 2012, Singh and Zimmerman 2015). While a number of factors may affect sleep in each individual, the process of falling to sleep is an operant behavior that is under stimulus control, and is therefore, able to be learnt (Blampied and Bootzin 2013).

Functional behavioral assessment (FBA) is an evidence-based approach to the formulation of intervention. FBA uses a combination of direct (e.g. observation) and indirect measures (e.g. parent interviews) in order to identify the variables impacting on the behavior. FBA has been used to devise treatments for a variety of challenging behaviors, including self-injury and non-compliance (Beavers et al. 2013, Hanley et al. 2014, Hansen and Wadsworth 2015, Hurl et al. 2016). There is evidence to demonstrate that such interventions for challenging behavior are more effective than non-function-based interventions, or those that are based on topography (Filter and Horner 2009, Dunlap and Fox 2012, Hurl et al. 2016). However, few studies have used FBA to inform treatments for SD in children with ASD (Friedman and Luiselli 2008, Jin et al. 2013, Papadopoulos et al. 2015).

FBA can be used to identify the antecedents (e.g. inconsistent bedtime and bedtime routine) and consequences (parental attention or access to preferred activities) of sleep interfering behaviors and to develop interventions to (a) reduce the occurrence of sleep-interfering behaviors; and (b) increase sleep conducive behaviors (e.g. lying quietly in bed). Variables that compete with sleep are modified and functionally equivalent or adaptive alternatives to the sleep interfering behavior offered (e.g. the use of a cuddly toy as a replacement for co-sleeping).

Most studies successfully treating SD in typically developing infants and children, and children with ASD have used extinction-based interventions where the reinforcement maintaining the SD (e.g. parental attention) is identified and removed (Vriend et al. 2011, Turner and Johnson 2013, Singh and Zimmerman 2015). Other promising approaches to SD maintained by external reinforcement include faded bedtime with response-cost (Moon et al. 2011, Papadopoulos et al. 2015), and modified extinction-based procedures, including graduated extinction and minimal check (Durand et al. 1996). Sleep education packages also incorporate behavioral interventions and have demonstrated some success (Malow et al. 2014). However, the effectiveness of all these techniques when the sleep interfering behavior is automatically reinforcing (e.g. stereotypic behavior) is less clear.

Repetitive and stereotypic behavior is a core diagnostic indicator of ASD (American Psychiatric Association 2013). This behavior has historically been defined as not serving any obvious function (Hanley et al. 2003, Cunningham and Schreibman 2008, DiGennaro Reed et al. 2012). As such, it is thought to be automatically reinforcing for the individual (Rapp and Vollmer 2005, Ahearn et al. 2007). Recent research however, suggests that stereotypic behavior can also be a socially mediated behavior that is maintained by external consequences (e.g. parental attention, or escape from demands) (Hanley et al. 2003, Roantree and Kennedy 2006, Cunningham and Schreibman 2008) and there is evidence for the effectiveness of interventions for this behavior. These include environmental enrichment (LeBlanc et al. 2000, Rapp 2004, Higbee et al. 2005, Watkins et al. 2011), non-contingent matched forms of stimulation (e.g. providing music as a form of auditory input as a replacement for vocal stereotypy) (Lanovaz et al. 2009, 2011, Love et al. 2012), differential reinforcement of other behaviors (Taylor et al. 2005), and response interruption (Ahearn et al. 2007, Love et al. 2012). If stereotypic behavior is indeed mediated by external consequences, then it is important to develop interventions that address the function of this behavior. To date, there are few studies that have documented the process of using FBA to formulate such interventions (DiGennaro Reed et al. 2012).

Stereotypic behaviors such as repetitive vocalizations and rocking have the potential to interfere with sleep, as these behaviors are incompatible with the behavioral quietude necessary for sleep onset and maintenance. Conversely, it is also possible that stereotypic behavior may serve to soothe children to sleep. To date, in spite of the high prevalence of stereotypic behavior in children with ASD, there is a paucity of research to have investigated the treatment of sleep interfering stereotypic behavior (Jin et al. 2013).

This study has four primary objectives: (1) to enhance the connection between assessment and treatment by developing evidence-based, parent-implemented, individualized, comprehensive, and socially valid interventions predicated on the results of FBA; (2) to explore the effectiveness of multi-component interventions in the treatment of sleep interfering behavior, including stereotypy; (3) to measure the maintenance of treatment effects over time; and (4) to better understand parents’ perspectives of the treatment process.

Method

Ethical clearance and informed consent

The relevant University Human Ethics Committee approved the study protocol, and the information sheets and consent forms that were provided to the parents and children.

Participants

Children included in this study were part of a larger study recruiting children with ASD and SD. Criteria for inclusion in the current study were: (1) a formal diagnosis of ASD (American Psychiatric Association 2013); (2) aged between 3 and 12 years; (3) non-verbal, or communicating using a maximum of 1–2 word utterances; and (4) parent-reported SD, defined as delayed sleep onset, frequent or prolonged NWs, and/or early morning awakenings. Minimal verbal ability was specified as an inclusion criterion in the current study, as this represents a unique group of children for whom verbally mediated interventions would not be suitable. Table 1 provides an overview of participant characteristics.

Table 1. Summary of participant characteristics.

Name	Age (Y–M)	Gender	Diagnosis	Medication
Matthew	4–2	Male	ASD	None
Mirasol	10–10	Female	ASD	Risperidone

Matthew. Matthew (pseudonym) was a 4 year, 2 month old boy with a pediatrician’s diagnosis of ASD. Matthew was non-verbal, and received an age-equivalent score of 11 months and 8 months, respectively, on the receptive and expressive subdomains of the Vineland Adaptive Behavior Scales - II (VABS-II; Sparrow et al. 2005).

Mirasol. Mirasol (pseudonym) was a 10-year, 10-month old girl who had been diagnosed by a pediatrician with ASD. Mirasol would communicate using occasional 1-word utterances and gestures. Mirasol received respective age equivalent scores of 2 years, 6 months, and 1 year, 9 months on the receptive and expressive subdomains of the VABS-II (Sparrow et al. 2005).

Settings

The clinical interview, and pre- and post-treatment assessments were undertaken in the family home, or at the University clinic. Treatments were implemented in the family home, by the children’s parents.

Dependent variables

Dependent variables are defined below, and are based on those described by Jin et al. (2013).

Sleep onset delay was classified as the number of minutes between the child being bid goodnight, and sleep onset. Sleep-interfering behaviors were defined as behaviors which negatively affected the child’s ability to settle to sleep. These included stereotypic behaviors that did not appear to be sleep conducive or soothing, seeking out activities or items, and so on. NWs were defined as the child waking following initial sleep onset. The duration of awakenings was recording from the time the child was deemed to be awake, to the time at which sleep onset resumed. Co-sleeping was categorized as parent-initiated co-sleeping (i.e. the parent lay with the child in the child’s bed until they fell asleep) and child-initiated co-sleeping (i.e. the child slept in their parents bed). Each of these behaviors was documented from the time the child was bid goodnight, to the time when the child woke to begin the day.

Outcome measures

Clinical interview. A pre-treatment clinical interview was conducted with each family to gather information about each child’s developmental history, the history of SD, the family context, and the environmental context of the SD. The post-treatment clinical interview gathered information about each parent’s experience with the assessment and treatment process.

The sleep assessment treatment tool (SATT). The SATT (Hanley 2005) was administered with each family during the pre-treatment clinical interview, as part of the FBA process. The SATT is a functional assessment tool used to categorize the nature of SD, to identify environmental variables that may be contributing towards the SD, and to determine parents’ goals for their children’s sleep (Jin et al. 2013).

Parent-reported sleep diaries. Parents recorded sleep diaries each night, during all phases of the study. Diaries recorded: (1) the frequency, duration, and setting of daytime naps; (2) the time that the child was put to bed in the evening, time of sleep onset, frequency of curtain calls (bids for parental attention after the child was put to bed) CCs, child behavior during CCs, parent responses to that behavior, and the setting of sleep onset; (3) the frequency and duration of NWs, child behavior during awakenings, and parent responses to awakenings; and (4) the time of morning waking.

Videosomnography (VSG). Swann Advanced-Series DVR4-1200, nighttime, infrared video cameras were used by parents to record video footage of the children’s sleep from bed-time to arising on at least 30% of nights.

It became evident during the assessment process that stereotypy was interfering with sleep for both the children presented here. Unfortunately the video equipment used did not capture audio recordings, meaning that this behavior was unable to be accurately coded retrospectively. Parents recorded the occurrence of vocal stereotypy, as a discrete event, on the sleep diaries.

Treatment acceptability. The TARF-R (Reimers et al. 1992) is a 20-item parent-report questionnaire, in which responses are recorded using a 7-point Likert scale. Seventeen items on the TARF-R examine ratings of treatment acceptability, while 3 items address the severity of the problem and parents’ understanding of the treatment approach. The TARF-R was administered post-intervention.

Procedures

FBA. FBA data were gathered using a combination of the SATT, sleep diaries and VSG.

Baseline. Baseline data were gathered for 14 and 27 days for Matthew and Mirasol respectively. During baseline, parents were asked to avoid any modification to their child’s sleep routines, or their responses to their child.

Intervention. Intervention immediately followed the conclusion of baseline and was individualized for each child, based upon the antecedent and consequence variables affecting their sleep.

Follow-up. One week’s video and diary short- and long-term follow-up data was gathered 5–6 and 11–12 weeks post-intervention, respectively.

Assessment results and treatments

The nature of the SD, those variables precipitating or maintaining it, the hypothesized function of the SD, and interventions are presented in Table 2.

Table 2. Problem behavior, factors precipitating and/or maintaining behavior, hypothesized function, and intervention approach for Matthew and Mirasol (based on Blampied and Bootzin 2013).

	Problem behavior/s	Factors thought to be precipitating and/or maintaining behavior	Hypothesized function	Intervention
Matthew	Frequent CCs	Parent attention; inconsistent sleep location and bedtime; loss of pacifier	Attention	Extinction; restoration of sleep position; pacifier cuddly; consistent sleep onset in crib; consistent bedtime routine; social story
			Tangible
	Frequent and prolonged NWs	Parent attention; loss of pacifier; vocal stereotypy;	Attention	Extinction; restoration of sleep position; pacifier cuddly; social story; white noise
			Self-stimulatory
Mirasol	Bedtime resistance	Access to preferred items; social attention; inconsistent bedtime and bedtime routine	Tangible	Consistent bedtime routine and bed time; social story; neutral pre-bedtime activities;
			Attention
	Delayed SOL and frequent CCs	Social attention; Inconsistent bedtime and bedtime routine; flicking light bulb; access to preferred items; vocal stereotypy	Attention	Extinction; consistent bedtime routine and bedtime; social story; neutral pre-bedtime activities; removal of preferred items; white noise
			Self-stimulatory
			Tangible
	Frequent and prolonged NWs	Social attention; flicking light bulb; access to preferred items; vocal and motor stereotypy	Attention	Extinction; visual aid; social story; removal of preferred items; white noise
			Self-stimulatory
	Unwanted co-sleeping (Sleep onset in Child’s bed; NWs in parents bed)	Social attention	Tangible	Extinction; visual aid; social story;
			Attention

CCs: curtain calls; NWs night awakenings; SOL: sleep onset latency.

Matthew

Matthew’s primary sleep problems were frequent CCs, and frequent and prolonged NWs. Matthew would occasionally fall asleep on the couch, and be transferred to his crib. Otherwise, he was put to bed between 7 and 8 pm each night. The results of the FBA revealed that when put to bed awake, Matthew would call out to his mother, or cry, at which point his mother would intervene. These CCs were most often precipitated by the loss of his pacifier.

Matthew’s mother would restore his sleep position, give him his pacifier, and briefly soothe him before leaving the room. CCs were hypothesized to serve two different functions: (1) to gain parental attention (attention); and (2) to obtain his pacifier (tangible).

According to the FBA, three factors contributed to the frequency and duration of Matthew’s NWs: vocal stereotypy, parental attention, and loss of pacifier. The vocal stereotypy consisted of humming and squealing, and often escalated into repetitive motor movements (e.g. sitting up, bouncing in his crib). His parents ignored Matthew’s stereotypic behavior. If Matthew woke and was upset and/or made bids for parent attention, his parents would respond as described for CCs. While both signaling and stereotypy were thought to be sleep interfering, they were hypothesized to serve different functions. Signaling was reinforced by parental attention (attention) and provision of the pacifier (tangible). By contrast, the stereotypic behavior appeared to be automatically reinforcing or self-stimulatory, as it was maintained in the absence of any external reinforcement. Matthew’s parents’ goals were for him to: (1) sleep through the night, without NWs; and (2) to settle to sleep independently in his crib.

Matthew’s treatment consisted of several components. White noise was used as a treatment for vocal stereotypy. An Audio Box FM MP3 player with speakers was provided which played an MP3 file of white noise, at a 50 dB volume. This was turned on when Matthew was put to bed, and turned off at 6am, when it was time for him to get up. The researchers hypothesized that white noise would minimize the reinforcing value of vocal stereotypy by masking auditory feedback; and provide matched stimulation that was less likely to compete with sleep onset and help Matthew develop a stimulus association between white noise and sleep onset. Pacifier use was maintained as it was his parents’ preference. It was incompatible with vocal stereotypy, and seemed to promote sleep onset. To reduce the need for parent intervention (and treat CCs), Matthew was provided with a soft teddy that had a pacifier connected to it. This enabled Matthew to find his pacifier independently.

To reduce parental attention maintaining CCs and NWs, Matthew’s parents placed him in his crib while awake so that he learnt to settle to sleep in his natural sleep environment. Matthew’s parents responded to CCs and NWs by restoring the sleep position, and physically prompting him to find his pacifier. Matthew was not provided with any verbal feedback, or other forms of parental attention, and they then left the room. A social story was used to describe the new expectations and bedtime procedures. This was read to Matthew every night, prior to putting him to bed. Matthew’s treatment lasted for 68 days, and consisted of three phases.

Phase 1. During Treatment Phase 1, all treatment components were implemented concurrently.

Phase 2. After 16 nights of intervention, the white noise generator stopped working. White noise was not available for 21 days. This resulted in what could be seen as an inadvertent treatment reversal. No other changes were made to intervention during this time.

Phase 3. The use of white noise was reinstated, along with continued implementation of the other components of the intervention.

Mirasol

Mirasol demonstrated multiple sleep problems, including bedtime resistance, delayed SOL, frequent CCs, frequent and prolonged NWs, and unwanted co-sleeping. FBA indicated that these sleep problems were maintained by a combination of factors. Bedtime resistance appeared to be maintained by an inconsistent bedtime and bedtime routine, transition from a preferred to non-preferred activity (bed), and reinforcement for bedtime avoidance (e.g. through continued play with preferred activities). Delayed SOL, CCs, and NWs appeared to be maintained, at different times, by parental attention, access to preferred items, and vocal and motor stereotypy. The stereotypy itself was hypothesized to have two possible functions. At times, this behavior appeared to be automatically reinforcing, as it occurred in the absence of any other form of extrinsic reinforcement. However, at times, possibly reinforcing parental attention was provided in response to stereotypic behavior (i.e. Mirasol’s mother would verbally interact, and lie with her). The outcomes of FBA necessitated a multi-component intervention, to address the multi-functionality of these sleep problems.

To reduce the likelihood of bedtime resistance, Mirasol’s mother was asked to establish a bedtime routine with neutral activities. A bedtime of 9 pm was established, as this was the time at which sleep onset was likely to occur within 15 min of being put to bed. A wake time of 7am was also implemented, regardless of the frequency or duration of NWs. White noise was used to treat sleep interfering vocal stereotypy (as above). An extinction procedure was implemented to eliminate the reinforcing effects of parental attention during sleep onset and NWs. Using this procedure, Mirasol’s mother would leave the room immediately upon bidding Mirasol goodnight. If Mirasol left the room at any point throughout the night, her mother would redirect her back to her bedroom with minimal interaction (for example, with no verbal instructions or eye contact), restore her sleep position and leave the room. Self-stimulatory behavior that occurred at any stage was ignored. Access to activities and food that reinforced NWs or delayed sleep onset were removed, and doors to living rooms in the house were secured. Finally, a social story was developed which described changes to the sleep routine and environment, and helped her to understand newly established expectations around sleep. This was read to Mirasol each night as part of the bedtime routine.

Experimental design

An AB case study design was employed. The individual complexities of each child meant the conceptualization of each case and its corresponding treatment plan was exclusive to each child. Multiple sources of data were collected, across a variety of means (i.e. VSG and diaries), to triangulate the findings.

Interobserver agreement

VSG was compared with sleep diary data in order to assess the reliability of sleep diary recordings. VSG data were compared with the sleep diaries on the following dimensions: (1) the time that the child was put to bed; (2) the frequency of CCs; (3) sleep onset time (when parents were able to detect this); (4) the frequency of NWs; (5) the duration of NWs; and (6) the time at which the child woke to begin the day. The percentage of agreement between the sleep diaries and VSG data were calculated using the formula: [Agreements/(Agreements + Disagreements)] × 100%. Interobserver agreement (IOA) data were collected for 34% of sessions across study phases, for Mirasol. The percentage of agreement between observers was 92%. IOA data were collected for 42% of sessions for Matthew. The percentage of agreement between observers was 91%.

Results

Matthew

The frequency of CCs and the frequency and duration of NWs is presented in Figure 1. In the case of Matthew, CCs were recorded as responses to sleep interfering behaviors that were not stereotypic behaviors (e.g. calling out or crying) as stereotypic behavior was ignored.

Figure 1.

Sleep outcomes for Matthew: CCs, frequency and duration (minutes) of night time awakenings across baseline, intervention and follow-up (43 days post-intervention) phases

During baseline, there were between 0 and 3 CCs each night. This reduced to zero on the first night of intervention, and was generally maintained during short- and long-term follow-up. On one occasion during Phase 3, at least 10 CCs occurred. This was an evening in which fireworks were being used nearby.

During baseline, Matthew would generally wake once per night, with the exception of four nights in which no awakenings occurred. From intervention Phase 1 Matthew continued to wake once or twice each night, except for three nights with no awakenings. From intervention Phase 2 (removal of white noise) awakenings decreased to zero or 1 awakening each night. From intervention Phase 3, there was a consistent reduction in the frequency of awakenings. During the final two weeks of intervention, awakening occurred on only three nights. During short-term follow-up awakenings occurred on only two nights, and during long-term follow-up no awakenings occurred.

Baseline duration of awakenings was 90–360 min. During intervention, this duration greatly reduced, with 13 out of the 28 awakenings lasting for 15 min or less, and only seven of the awakenings exceeded the baseline minimum of 90 min. During short-term follow-up, the two awakenings lasted 3 and 93 min. No awakenings occurred during long-term follow-up.

Mirasol

Treatment was provided over a period of 35 days, at which point a stable reduction in sleep interfering behaviors was observed. Short-term follow-up data were gathered 43 days following the conclusion of intervention. Long-term follow-up data were unable to be gathered for Mirasol as she had been placed in temporary residential care owing to on-going aggressive behavior.

Sleep onset latency (in minutes), co-sleeping, and the frequency and duration of NWs for Mirasol, is presented in Figure 2. A filled circle indicates parent-initiated co-sleeping at sleep onset. A transparent circle indicates no parent-initiated co-sleeping. Child-initiated co-sleeping, during NWs, is represented using the ‘X’ symbol. During baseline, the SOL period was typically between 30 and 60 min, with occasional nights with longer latency. While there are some nights of reduced SOL during treatment, there is no clear evidence of a treatment effect. At short-term follow-up, SOL increased from baseline.

Figure 2.

Sleep outcomes for Mirasol: sleep onset latency (minutes), frequency and duration (minutes) of night time awakenings across baseline, intervention and follow-up (43 days post-intervention) phases

During baseline, parent-initiated co-sleeping occurred every night. Child-initiated co-sleeping occurred during 7 out of 27 nights. Parent- and child-initiated co-sleeping and NWs were successfully eliminated during intervention. It is possible that the elimination of parent-initiated co-sleeping during the sleep onset period, may have contributed toward the increase in SOL.

During baseline there were up to 3 awakenings per night. These awakenings lasted between 28 and 270 min. After five nights of intervention, night waking ceased, with the exception single awakenings on two nights. These awakenings lasted 61 and 238 min. During short-term follow-up there continued to be an absence of NWs.

Treatment acceptability

Results of the TARF-R are presented in Table 3. Results reflect high maternal ratings of overall treatment acceptability (113/119). Each dimension of acceptability was also rated favorably, with a range of 18–21 out of 21 across dimensions of reasonableness of intervention, willingness to implement intervention, cost, side-effects, effectiveness, and level of disruptiveness.

Table 3. Maternal ratings of the TARF-R for each participant.

Variable scores	Mirasol	Matthew	Maximum score
Reasonableness	18	18	21
Willingness	21	20	21
Cost	21	21	21
Side-effects	21	19	21
Effectiveness	18	18	21
Disruption/time	21	18	21
*Problem severity	14	10	14
*Understanding treatment	6	7	7
Total acceptability	113	114	119

^*Not included in overall treatment acceptability score.

Each parent also indicated that they had a good understanding of the treatment process (6-7/7).

Discussion

Treatments based on the outcomes of FBA, resulted in a reduction in the frequency and duration of NWs for each participant, and a reduction in CCs for Matthew. Each child also learnt to settle to sleep with greater independence. For Mirasol, this meant elimination of parental presence during sleep onset and NWs. Improvements were maintained at follow-up for each participant, though long-term follow-up was unable to be recorded for Mirasol.

While SOL reduced for Mirasol this remained variable possibly owing to the reduction in co-sleeping. Nonetheless, Mirasol’s mother felt that her goal of increasing independent sleep onset had been achieved.

Both parents included in this study felt they had a good understanding of the treatment approach and process, and its relevance to their child. Parents also rated the acceptability of treatment approaches favorably.

This study identifies several key considerations when treating sleep problems in children with ASD. Although many of the presenting sleep problems were the same (i.e. frequent and prolonged NWs) FBA indicated the underlying cause of the sleep problems to be unique to each individual. Many of the sleep problems were also multifunctional, and required careful combination of intervention strategies. The use of FBA enabled the researchers to go beyond the presenting problems, and to tailor treatment to target underlying roots of SD for each individual.

The identification of sleep interfering vocal stereotypy was an unexpected finding, scarcely documented in the literature (Jin et al. 2013). While the topography of the vocal stereotypy was similar, the FBA revealed a difference in the function of this behavior across participants. For Matthew, the behavior did not result in additional external reinforcement and was therefore hypothesized to be automatically reinforcing. By contrast, for Mirasol, the behavior appeared to be multi-functional, as it appeared to be reinforced, at least in part, by parental attention. As a result, these topographically similar behaviors required different approaches to treatment. This outcome highlights the importance of using FBA to determine the function of sleep interfering behaviors.

White noise offered a matched form of auditory stimulation (Lanovaz et al. 2009, 2011, Love et al. 2012) and may have reduced the potential reinforcement generated by engaging in vocal stereotypy. This appears to be one of few studies to have targeted sleep interfering vocal stereotypy in children with ASD. The results of this study highlight the difficulty of measuring and conceptualizing stereotypies. While there is tentative evidence for white noise as a treatment for sleep interfering vocal stereotypy, there were other possible mechanisms of action (e.g. it may be intrinsically calming) and we did not determine that it reduced vocal stereotypy or that such a reduction was pivotal in effecting change in the typography of the SD.

Another obvious benefit of FBA was that it enabled tailoring of treatment to the characteristics of the family context. This was important as the family dynamics, parental goals and motivation, support networks, and physical home environment were unique. Parents were consistently involved in the assessment and treatment process, and were integral to the overall functioning of the research process. During post-treatment discussion families reported that they were pleased with being a part of a collaborative process which emphasized the importance of working with families to identify and treat SD. This finding is consistent with other studies that have emphasized the value of shared decision-making on treatment outcomes (Weiskop, Richdale and Matthews, 2005, Jin et al. 2013, Turner and Johnson 2013).

Limitations of the current study

One of the primary limitations of this study is the lack of an experimental research design. Nonetheless the case-study design does fit with the underpinnings of FBA being an intervention designed around the specific functions of a rich topography of behavior which, by definition, is different for every case. The use of a case study design, allowed the researchers to retain important idiosyncratic data, and a rich description of how treatments are able to be individualized according to children’s presentations and contexts.

A second limitation is the lack of recordings of stereotypic behavior. While unavoidable in this study, employing equipment able to provide direct measurement of this behavior during all phases of the study is important.

A third limitation is the inability to establish whether the stereotypy did in fact interfere with sleep as opposed to having a soothing function. However, if the stereotypy was interrupted, and it was self-soothing, then we would have seen an increase in SD, rather than a reduction. Therefore, the authors tentatively assume that this was a sleep interfering behavior.

A final limitation of the study is that the researchers were unable to obtain long-term follow-up data for Mirasol. While this was beyond the control of the research team Matthew’s long-term improvement highlights the importance of recording change in behavior over time.

Clinical implications

The results of this study highlight the importance of using FBA to identify causal mechanisms impacting upon sleep for each individual especially given that interventions based on FBA are more likely to be successful than those generically applied across children (Ingram et al. 2005, Filter and Horner 2009). Importantly, FBA also allows for family choice and preferences, rated highly by families participating in this study.

This study also provides evidence of the need to conduct FBA in order to determine the function of stereotypic behavior, as topographically behaviors may be maintained by different variables requiring different treatments. In many cases this may mean the use of multi-component interventions.

Another clinical implication is the need to assess stereotypic behavior, in order to differentiate whether this is something that interferes with or promotes sleep onset and to tailor resulting interventions so that (1) they include non-contingent access to an appropriate source of stimulation, and (2) they eliminate any reinforcement that is generated by the stereotypic behavior. In the case of vocal stereotypy, this may mean providing the use of an alternative source of auditory input.

While it is difficult to isolate the components of treatment that were responsible for changes in sleep for each individual, many practices were common across individuals. These include the use of white noise, visual supports, and factors that promote sleep hygiene. These findings also add to the existing evidence, supporting the use of extinction based procedures for sleep interfering behavior that is being reinforced by parental attention.

Recommendations for future research

An aim of the current study was to build on the existing literature into effective interventions for sleep disturbance in children with ASD. While FBA may indicate the need for multimodal treatments, it would be helpful to know whether components of treatment are effective alone, with similar presentations, or when used in combination, as well as which components of treatment are least intrusive for families.

Further research to investigate treatments for sleep interfering stereotypic behavior is needed. This behavior is a key diagnostic indicator of ASD, and is a behavior that appears to be related to SD (Reynolds and Malow 2011), yet we know little about how to treat it in the context of sleep intervention. Furthermore, we still do not understand whether the intensification of stereotypy in children with ASD and SD (Schreck et al. 2004), is the result, or cause of reduced sleep duration. Another consideration is to investigate whether sleep diaries could be modernized to allow for electronic recording, to best fit with how parents may naturally opt to record data. Unfortunately, actigraphy does not detect the presence or absence of vocal stereotypy.

Finally, one anecdotal finding was that treatment effects do have other benefits to the family. It is recommended that a more thorough investigation is undertaken of collateral benefits from improved sleep.

There remains the need for much more research to be undertaken. It is recommended that research continue to assess the use of FBA with SD in children with ASD, as well as to explore which types of treatment are most effective and acceptable to families.

Disclosure statement

The authors report no conflicts of interests and are solely responsible for the content and writing of this paper.