Research & Practice for Persons with Severe Disabililies2(XM, Vol. 29. No. 2. 122-134

copyright ZlHM byTASH

A Systematic Desensitization Paradigm toTreat Hypersensitivity to Auditory Stimuli

in Children with Autism inFamily Contexts

Robert L. Koegel. Daniel Openden, and Lynn Kern KoegelUniversity of Calitornia. Santa Barbara

Many children with autism display reactions to audi-tory stimuli (hat scent as if the stimuli were painful orotherwise extremely aversive. This article describes,within the contexts of three experimental designs, howprocedures of systematic desensitizntioti can he used totreat hypersensitivity lo auditory stimuli in three youn^children with autism. Stimuli included the sounds front avacuum cleaner, blender, hand-mixer, toilet flushing,and specific animal sounds from musical toys. A chcmg-inii criterion design was used and data were collected on(a) the number of hierarchical steps completed as com-fortable with the stimulus per week and (b) the meanlevel of anxietv per probe. A clinical replication wasimplemented using a replication of the desensitizationprocedures for three children. In addition, a systemaiicreplication acro.ss three different stimuli is presented fororw child in a multiple baseline. The data show thai thechildren s responses could be modified to the pointwhere they were comfortable with these noises. Further-more, this level of comfort was maintained at follow-up.The discussion suggests that the e.xtreme reactions to au-ditory stimuli many children with autism exhibit may hedecreased with procedures that have been .shown to beeffective with reducing phobias, and the possibility thatthe reactions mav be symptomatic of a phobia ratherthan actual pain.

The authors thank the families who participaied in this re-search. Wo also express our gratitude In Hill Fri.-;i and lo thestudents. Dcanny Cierner and Lisa Howe, who assisted withthe data collection and reliahility measures. Finally, we greatlyappreciate the t'eedbaek provided by IJr. George Singer andDr. Mike Gerber for their extensive j'eedhack on earlier draftsof this study.

Portions of the research reported in this study were sup-ported by Research Gnint MH2S2IO from the Nntional Insti-tute i>l' Mental Health and by US Department of EducationGrant #5S3l)-257-LO-B.

Address all correspondence and requests for reprints toRobert L. Koegel. ("ounseling/Clinical/School Psychology Pro-gram. Graduate School of Educalion. Univcrsily of California.Santa Barbara. CA y31()fvy4')(l. E mail: koegelCneducalion.ucsb.edu

DESCRIPTORS: desensitization. autism, hypersen-sitivity. auditory stimuti. families

Many childrun with autism arc described in the lit-erature as having auditory abnormalities, including re-ports of hypersensitive hearitip (Grandin & Scariano.t9S6: Hayes & Gordon. 1^77: Ney. 1979; Rimland.1%4: Rimland & Edelson. \W5). Since t%4. the Au-tism Research Institute has c[>llected data from over17.()()0 families ol children with autism. Data reveal thatapproximaiely 40% of parents of children with autismreported that their child exhibited some symptoms ofsound sensitivity (Rimland & Edelson. t995). Amongother hearing irregularities, children with autism haveheen reported to frequently display an intense aversionto auditory stimuli, which has led to the speculation thatthey may even experience hyperacusis, a cotidition inwhich exposure to particular sounds frequently causespain. The reaction can be so severe that an individual'sability to function is impaired and behaviors that aredisruptive, aggressive, self-injurious, or otherwise inap-propriate arc often displayed (Berkell. Malgeri. &Streil. 1996; Brown. 1999). Exacerbating the prtiblem isthat many children with autism are reported as beingmost sensiti\c to common everyday environmentalsounds (Vicker. 1993).

Unfortunately, many interventions designed to ad-dress sensory impairments in children with autism havenot been well validated (Dawson & Watling. 2000;Goldstein. 2000). The literature has further indicatedthat it has been difficult to demonstrate objective andreliable changes in auditory sensitivity (Gravel. t994;Rimland & Edelson. 199.̂ : Tharpe. 1999). Thus, well-controlled, reliable studies are needed to develop ef*fective interventions to address auditory- sensitivity inchildren with autism (Dawson & Watling, 20(H): Gold-stein. 2(HKI).

The literature has also suggested that many childrenwith autism display phobias (Howlin et a!.. 1973: Jack-son & King. 1982; Love. Mats(m.& West. 1990; Luisdii.197S), many of which tnay be related to the difficulties

122

Using a Systcmalic Dcscnsilizalion Panidigm 123

they have with iiuditory stimuli (Hcmsley, 1978). IntHher words, [he child's cxiremc aversion lo Ihcsestimuli may relate to an irrational fear of the stimulusrather than to pain associated with the stimulus. Sys-tematic desensiti/atii)n is a procedure typically used toircat phobias and is a coninion countcrconditioninj!procedure used with children (C enter, \^)H9). Some re-searchers have demonstrated that systematic desensiti-zation can be used to reduce fears for children withautism during common experiences, such as a dentalexamination (Euscre & Center, IV%).

The purpose of this study was to assess the effects ofa systematic descnsitization intervention progratn onthe apparent hyperscnsitiviiy of children with autism titcommon environmental auditory stimuli. Specifically,this research was designed to evaluate whether thesechildren's intolerant reaction to common everydaysounds (vacuum cleaner, blender, hand-mixer, toiletflushing, toys) could be modified using procedures ofdesensitization to the point where Ihe child would seemcomfortable with these stimuli.

Method

PariicipanisThree children, two boys and a girl, diagnosed with

autism were selected to participate in this study basedon their apparently severe hypersensiiiviiy to auditorystimuli. All ehildren were diagnosed with autism bytheir pediatrician and/or a California state agency spe-cializing in developmental disabilities aecording to cri-teria listed in the DltiiiiioMic anil Sidiisiiciil Muniuil ofMenial Disorders—Foitrih lidiiion (American Psychiat-rie Association. 1994). The children were subsequentlyreferred to the I'niversity of California Santa BarbaraAutism Research and Training Center for intervention.All demonstritted qualitative impairments in communi-cation and social development, and all demonstrated arestricted repertoire of interests.

Child 1. Eori, an Hispanic-American girl, was 3 yearsand 7 months of age at the start ol the study. Recentstandardized testing showed the following. On theVineland Adaptive Behavior Scales. Lori scored an ageequivalent ot" I year 4 months on the CommunicationDomain. 1 year 9 months on the Daily Eiving SkillsDomain. 7 months on the Sociali/atitin Domain, and 2years 9 months on the Motor Skills Domain, wilh anAdaptive Behavior Composite of I year 7 months. Loriattended a full inclusion preschool on the University ofCalifornia campus. On her first day of school. Lori'steachers noted that they were unable to take her lo thebathroom as she refused to enter the bathroom andcovered her ears every time the toilel flushed. Conse-quently, she had daily toileting accidents at school. Oh-servations at home indiealed that she did not react tothe toilel Hushing at home, which was much quieler.Preintervcntion probes confirmed thai Lori began put-

ting her hands over her ears in the school hallway as thechildren walked toward ihe bathroom, about 40 feetaway. In addition, she covered her ears and refused loenter the bathroom, even when other children were notpresent.

Child 3. Jamie, a Caucasian boy, was 2 years and 6months ol age at ihe start of the study. Recent stan-dardized testing showed ihe following. On the VinelandAdaptive Behavior Scales. Jamie scored an age equiva-lent of 1 year 7 months on the Communication Domain.1 year 6 months on the Daily Living Skills Domain, 1year 6 months on the Socialization Domain, and 3 years8 months on the Motor Skills Domain, with an Adap-tive Behavior Composite ol' 2 years 1 month. Prior tothe start of services Jamie's mother reported that hecould not play with many toys because of his intoler-ance to certain sounds. Specifically, she reported thathe avoided all toys with animal sounds, and when onewas turned on he placed his hanJs over his ears.screamed, cried, and ran away from Ihe toy. Jamie'smother reported that he had been sensitive to soundsall of his life, but at around 2 years of age. he begandisplayinj; extreme aversive reactions to the toys. Sheexpressed concern that his play was extremely limitedas a result of this behavior. In addition, Jamie becameupset at the sight of toys that were associated with ani-mal sounds, and consequently his mother constantlyavoided environments where similar toys were avail-able, such as ley stores and friends" homes. In addition,Jamie's mother was concerned that he may displayIhesc extreme behaviors in a preschool setting, wherethese types of loys are common. During preinterven-tion probes collected when in the toy room at [he Uni-versity of California Autism Center, Jamie began to eryat the sight of toys that made animal sounds and re-peatedly requested that the lo\ be put away (i.e., "no,no. no" or "all done"), if the noise was turned on. Jamieengaged in more severe disruptive behaviors, includingcovering his ears, screaming, crying, and attempting torun out of the room. Prior to intervention, observationswere also made at the family's home. Jamie's motherreported that she had put away all of the toys withanimal noises as a result ol Jamie's severe reaction tothe toys and was unwilling to take the toys out for abaseline probe.

Child 3. Jeff, was 2 years and 7 months of age at thestart of the study. Jeff was a Eurasian boy who livedwith both parents and a younger brother. Recent stan-dardized testing showed the lollowing. On the VinelandAdaptive Behavior Scales. Jeft scored an age equiva-lent of 1 year 5 months on the Communication Domain,1 year 5 months on the Daily Living Skills Domain. 9months on the Socialization Domain, and 2 years 9months on ihe Motor Skills Domain, with an AdaptiveBehavior Composite of 1 year 5 months. Prior to thestart of services. Jeffs mother reported that he ap-peared to be oversensitive to auditory stimuli, reacting

124 Koegel et al-

in a way that suggested such stimuli were inlolerahlc forhim. She began noiicing his aversive reaction to thesound of vacuum cleaners, blenders, and hand-mixerswhen Jeff was about 18 months old and reported thathis reaction had worsened over time. Consequently.Jeffs apparent hypersensitivity had made a drastic im-pact on the quality ot life for his family. For instance,they often avoided vacuuming their home altogether orbegan vacuuming only when Jeff was asleep or not inthe house. Similarly, they began avoiding other house-hold appliances, particularly the blender and the hand-mixer, that appeared to be painful for Jeff. Finally, theystopped going tti Blenders, a family favorite smoothieand juice bar. Jeff's mother adamantly expressed thefamily's growing concern over his inability to coexistwiih such stimuli and the inconvenience it caused theirfamily. Preintervention probes were performed in thecommunity and at the family's home prior tn the startof intervention. At the mere mention and sight of boththe vacuum cleaner and the hand-mixer. Jeff engagedin such behaviors as running away, crying, screaming,forcefully placing his hands over his ears, and grindinghis teeth. When either stimulus was turned on. thesebehaviors greatly increased and intensified. Similarly, apreinlcrventiiin prt)be laken at Blenders {smoothie andjuice bar) was terminated when Jeff began engaging inthe same behaviors in the surrounding shopping centerand was unable to enter the store.

SellingLori's sessions were all implemented in her full in-

clusion preschool setting. The students' bathroom waslocated down the hall from the classroom (about 35yards). The bathrot)m had two toilets and two sinks.This was her only setting, because the problem was noiobserved at any other time. During all of Lori's ses-sions, a clinician from our center was present whileLori's teacher took her to the bathroom.

Intervention sessions for Jamie were all implementedin a small elinic room located on the University campus.The clinic room contained a large number of children'stoys and a small table with chairs. Jamie's mother anda clinician from our center were present during ail ses-sions, In addition, postintervention probes were col-lected at Jamie's home during follow-up to assess forgeneralization to a new setting with different toys thatalso make animal sounds.

For Jeff, sessions for the vacuum cleaner and thehand-mixer took place in the family's home. Preinter-vention. intervention, and follow-up measures were col-lected in one of four rooms in his house: the sunroom.playroom, dining room, and living room. Jeffs motherand a clinician from our center were present during allsessions. Sessions for the blender also took place in thefamily's home and in the same rooms as the vacuumand the hand-mixer. However, additional sessions were

implemented at Blenders. Baskin Robbins. and Star-bucks stores for generalization.

Design and ProcedureThe effects of systematic de.sensitization on auditory

hypersensitivity were assessed within the context ofthree experimental designs (Barlow & Hersen, iy,S4). Aclinical replication was implemented using a replicationof the desensitization procedures for all three children.A changing criterion design was used to systematicallyadvance each child through steps in a desensitizationhierarehy. Finally, a systematic replication across threedifferent stimuli (vacuum, blender, and hand-mixer) ispresented for Jeff in a multiple baseline.

BaselineFor Lori, data were recorded on her reaction to the

toilet flushing when school staff took her to the bath-room. For Jamie, data were recorded on his reaction tothe sight and sound of toys that made animal sounds:specifically, a Mattel "Sec and Say" was used to assesshis reaction to these noises during all phases of theintervention. For Jeff, data were recorded on his reac-tion to the mention, sight, and use of the vacuumcleaner and hand-mixer under normal household con-ditions while his mother engaged in typical, everydayinteractit)ns and activities with her son. Similarly, datawere recorded on his reaction to the blender when hismother took him to Blenders.

InierventionFor all three children, intervention steps were devel-

oped by a team that included our staff and the indi-viduals who interacted most frequently with the childwhen the hypersensitivity was occurring. For Lori, thiswas her teacher: for Jamie and Jeff, these were theirmothers. These individuals interacted with the childduring intervention while a clinician assisted with thefading steps. The parents and teachers were asked notto move forward in the hierarchy or to present the tar-geted stimulus tt> the child without the clinician present.with the exception of Jeff. Jeff's sessions were con-ducted weekly by ihe clinician, and Jeffs mother wasencouraged to use the most recently completed step inthe hierarchy throughout the week if it was convenientfor the family and if Jeff appeared comfortable. Theclinician kept in close contact with Jeffs mother duringthe week by telephone and e-mail. For all children, thecriterion for completing a step in their respective hier-archies was two to four consecutive 3-minute intervalsscored as "comfortable."' Specific steps for each childare described below and are presented in Tables 1, 2.and 3 for Lori, Jeff, and Jamie, respectively. Furtherdetails pertaining to the length of steps and the numberof steps eompleted per day or per week are describedfor each child in the Results section.

For Lori, steps 1 through 4 were designed to increaseher comfort with the toilet area. Step 1 consisted of

Using a Systematic Dcsi;nsiliziition Paradigm 125

Table 1Systematic Desensitization Hierarchy for Lttri

Step#

Step#

Hierarchy Descriplion

1 Toilet is not flushed while Lori walks by the bathroom door. Tlie bathroom door is closed completely.2 Toilet is not flushed while Lori walks by the bathroom door. The bathroom door is slightly cracked.3 Toilel is not Hushed while Lori walks by the bathroom door. The bathroom door is 1/4 way open.4 Toilet is not (lushed while Lori walks by the bathroom door. The bathroom door is 1/2 way open,5 Toilet is not flushed while Lori walks by the bathroom door. The bathroom door is completely open,6 Toilet is flushed repeaiedly while Lnri is approximately 73 feet from the bathroom door.7 Toilet is flushed repeatedly while Lori is approximately 50 feel from the bathroom door.8 Toilet is tlushed repeatedly while Lori is approximately 2? feet Irom the bathroom door.9 Toilet is flushed repeatedly wtile Lori is approximately 20 feet from the bathroom door.

10 Toilet is flushed repeatedly while Lori is approximately 10 feel from Ihe bathroom door.11 Toilet is flushed repeatedly while Lori is at the bathroom door.12 Toilet is flushed repeatedly while Lori is inside the toilet stall. Door to toilet stall is open.13 Toilet is flushed repeatedly while Lori is inside Ihe toilet stall. Door to toilet stall is closed.

Table 2Systematic Desensitization Hierarchy for Jamie

Hierarchy Description

1 Animal sounds are played repeatedly outside of the clinic room (approximately 20 feet from the door). The clinicroom door is closed completely.

2 Animal sounds are played repeatedly outside of the clinic room (approximately HI feet horn the door). The clinicroom door is closed completely.

3 Animal sounds are played repeatedly outside of the clinic room (approximately 5 feet from the door). The clinicroom door is closed completely.

4 Animal sounds are played repeatedly outside of the clinic room (approximately 4 feet from the door). The clinicroom door is closed completely.

5 Animal sounds are played repeatedly jusl outside of—but held away from—the clinic room door. The clinic roomdoor is closed completely.

6 Animal sounds are played repeatedly just outside of ihe clinic room and pressed against ihe clinic room door. Theclinic room door is closed completely.

7 Animal sounds are played repeatedly jusl outside of the clinic room. The clinic room door is slightly cracked.8 Animal sounds are played repeatedly jus) outside of the clinic room. The clinic room door is 1/4 way open,y Animal sounds arc played repeatedly jusl outside of the clinic rootn. The clinic room door is 1/2 way open.

10 Animal sounds are played repeatedly inside Ihe clinic room by clinician.11 Animal sounds are played inside the clinic room by clinician. Jamie spontaneously verbally requests that the

clinician play various animal noises.12 Animal sounds are played repeatedly by Jamie's mother and/or alternated between Jamie and his mother.

having Lori etiter the hall whcti the bathroom door wasclosed. Steps 2 through 4 were desigtied to graduallyopen the door of the bathroom. The remainder of thesteps (steps 5 through 13) involved Lori gradually mov-ing closer to the bathroom with the toilet Hushing.

For Jamie, the animal sounds were played repeatedlyand became increasingly louder as they were graduallymoved closer to the playroom where Jamie and hismother engaged in his favorite activities, such as toyplay or eating a snack. In steps 1 through 9. Jamie wasunable to see the toy playing animal sounds; in steps 10.11. and 12, he could see and interact with the toy whilethe attimal sounds were played repeatedly. Jamie's sys-tematic desensitization program was completed in onesession, and lollow-up data were subsequently collectedat home. In addition, the clinician kept in dose contactwith Jamie's mother by telephone and e-mail to discussJamie's progress and ability to maintain stable levels ofcomfort with similar toys at home.

For Jeff, steps 1 and 2 placed a turned-off vaeuum.

blender, or hand mixer int{) his environment and tar-geted his comfort with seeing the stimulus. Steps 3through 12 allowed Jeff to become comfortable withthe sound of an out-of-sight vacuum, blender, or hand-mixer, becoming increasingly louder as it was movedcloser to where he was playing. Finally, in steps 13 and14, Jeff was able to both see and hear an operatingvacuum, blender, or hand-mixer. Jeff's comfort with theblender did not generalize to Blenders; therefore, in-tervention was also implemented in the communitywhere the smoothie shop was located. Table 4 presentsthe five additional hierarchical steps necessary for thatsetting. Step 15 simulated walking into Blenders in theehild's home setting. In step 16, a blender was turnedoff and on repeatedly to approximate the making ofjuice and smoothies inside the store. Steps 17 and 18were designed to present the sound of a blender instores other than Blenders (i.e., Baskin Robbins andStarbucks), and in step 20 Jeff entered Blenders whilejuice and smoothies were being made.

126 Koegel et al.

Table 3Systematic Desensitization Hierarchy for Jeff

Step#

Step#

Hierarchy Description

0 Vacuum/Blender/Hand-mixer is mentioned prior to being used.1 Vacuum/Blender/Hand-mixer is lurned off and placed out of sight in an adjaceni room, the sunroom. Jeff is

gradually Iransilioned into ihc room with the stimulus.2 Vacuum/Blender/Hand-niiser is turned off and placed in any room Jeff enters. If Jeff remains in any room for an

extended amount of time. Ihe stimulus is moved lo different locations within the same room.3 Vacuum/Blender/Hand-mixer is lurned on in ihc back master bedroom. Bolh the bedroom door and the hallway

door are closed.4 Vacuuni/Blender/Hand-mixer is turned on in ihe baek bedroom. The bedroom door is open and the hallway door

remains closed.5 Vacuum/Blender/Hand-mixer is turned on in the back bedroom. The bedroom door is closed and the hallway door

is completely open.f) Vacuum/Blender /Hand-mixer is turned on in the back bedroom. T h e bedroom door is l/4-way open and the

hallway door is completely open.7 Vacuum/Blender /Hand-mixer is turned on in the back bedroom. The bedroom door is 1/2-way open and the

hallway door is completely open.S Viicuum/Blender/Hand-mixer is turned on in the baek bedroom. Both the bedrot)m door and the hallway door are

completely open.y Vacuum/Blender /Hand-mixer is turned on in the ba lhroom. Both the ba ihroom door and ihe hallway door are

completely open.10 Vacuum/Blender /Hand-mixer is lurned on in Jef fs bedroom. The bedroom door is l/4-way open and the hallway

door is open.11 Vaeuum/Blender /Hand-mixer is turned on in Jef fs bedroom. Both ihe bedroom door and the hallway door are

eompletely open.12 Vacuum/Blender /Hand-mixer is tu rned on in the sunroom just outs ide of Jeff's p layroom, yet remains out of sight.13 Vacuuni /Btender /Hand-mixer is turned on in the sunroom just outside of Jeff s playroom and is visible.14 Vacuum/Blender /Hand-mixer is tu rned on in the same room as Jeff and is in sight.

Table 4Systematic Desensit ization Hierarchy: Addi t iona l Steps Implemen ted for the Blender for Jeff

Hierarchy Description

15 Blender is turned on while Jeff and his mothe r are outside. Jeff and his mothe r en te r the house (where hisfavorile toys are available) to simulale entering Blenders.

1(S Blender is turned off and on repeatedly to simulate sound made at Blenders.17 Jeff and his mother enter Baskin Robbins while blender is turned on.lH Jeff and his mother enler Starbucks while blender is lurned on at.19 Jeff and his mother play with his favorite loys near the entrance of Blenders.20 Jeff and his mother enter Blenders while blender is turned on.

Follow-upFoUuw-up probes were conducted after the comple-

tion of intervention for each child under conditionsidentical to baseline. Follow-up probes for Lori weretaken when her teacher took the children to regularlyscheduled toileting sessions. Jamie and his motherplayed together while follow-up probes were taken withboth stimuli used during the desensitization program (aMattel "Sec and Say" toy) and toys his mother broughtin from their home that made animal sounds, and towhieh he had previously responded negatively. Addi-tionally, follow-up data were collected in the family'shome for generalization. Jeffs mother was instructed toengage Jeff in typical, everyday interaetions and activi-ties under normal household conditions and data wererecorded on Jeffs reaction to the mention, sight, anduse of each auditory stimulus.

Dependent MeasuresDependent variables were (a) the number of hierar-

chical steps completed with the child's anxiety leveljudged as comfortable per week and (b) the mean levelof anxiety per session. Criterion for a step completedwas two to four consecutive 3-minute-intervals scoredas "comfortable."

An interval recording system (in continuous 10-second intervals) was used to rale the children as ap-pearing et)mfortablc, exhibiting mild or high anxiety, orappearing as if the auditory stimulus was intolerable.Comforiahle was defined as the absence of any anxietyrelating to the stimulus and the child appeared to herelaxed, engaged happily in typical play and interae-tions, and unaffected by the sighi or sound of the stimu-lus. Mild anxieiy was defined as engagement in behav-iors such as delaying attention to a game or activity.

Using a Systematic Desensili;^aiion Paradigm 127

short whining or whimpering, and brief periods of thechild covering his or her ears with his or her handswhen the stimulus was introduced. These behaviorsbriefly delayed but did not interfere with the activity.Hi^h anxiely was defined as the child exhibiting behav-iors such as slowly mt)ving away from the sight or soundof the stimulus, whining, and covering his or her cars tothe extent that the child eould not participate, play, orinteract appropriately. Intolerable was defined as thechild exhibiting behaviors that suggested that the sightor sound of the stimulus was a painful experience: run-ning away from a game or activity, crying or screaming.pushing his or her hands forcefully over his or her ears,sweating, shaking, and grinding the teeth.

Observer ratings for each lO-second interval weregiven numeric values (comfortable, 0; mild anxiety. 1;high anxiety, 2; and intolerable, 3). Averages of thesescores were calculated every 3 minutes (18 intervals) toobtain a mean anxiety seore and plotted as probesalong the ordinates in Figures 2, 3, and 4.

ReliabilityUsing the same interval recording system described

above, two undergraduate psychology students, one

who was blind to the experimental conditions, indepen-dently recorded data for at least 33'X) of all sessions.Data were scored via videotapes presented in randomorder. Interobserver agreement was calculated by di-viding the number of agreements by the total numberof agreements plus disagreements and multiplying by100. An agreement was defined as both observers rat-ing the child identically (comfortable, mild anxiety,high anxiety, intolerable), whereas a disagreement wasdefined as any discrepancy between the observers' re-cordings. Mean interobserver agreement results were96.8% across all sessions, with a range of 83% to 100%.

Results

During the systematic desensitization interventionprogram, observers reliably judged all children to be-come eomfortable with inereasing steps in exposures toeach stimulus. At the end of treatment, each child wasjudged to be comfortable with the stimulus in sight andoperated or turned on. In contrast to baseline sessions,observers never judged the stimulus, at sequentialsteps, to be intolerable for any of the children onceintervention began.

Baseline

1 4 -

VSlCfl. I LSn i ion t

inlDlcniMn•E 2-

0 -J-»—«

Baseline

12-

10-

Follow-up

1—1—I—I—I—I—I—I—I—I—r

Days

Follow-up

• • A

Jamie(Animal Noises)

I T T \ \ \ \ 11 \

1 1 1 1 1 1 1 1

Baseline

Lon(Toilet Flush)

I I I

Follow-up

-/I

(Vacuum)T I I I I I I I I I I I I I I I I I I I I I 1 I

Weeks Weeks

Figure 1. Number of sleps in the systematic desensitization hierarchy completed as comfortahit; per session and per for each

128 cei;! et al.

Figure 1 presents the number of hierarchical stepsLori. Jamie, and Jeff completed per week during base-line, treatment, and follow-up conditions for the toiletflush, animal noises, and vacuum, respectively, as aclinical replication. Criterion for a step completed wastwo to four consecutive 3-minute intervals scored ascomfortable.

In the top graph, baseline data indicate that Lorifailed to reach criterion levels of comfort at step 11(toilet is flushed while Lori is al ihe bathroom door),and sessions were terminated due to behaviors indieat-ing that the toilet flushing was intolerable for her. Incontrast, steps completed during intervention reached astable level of comfort in each session. Completed stepsper day ranged from five to eight steps: steps 1 through5 were completed during day 3 and steps 6 through 13were completed during day 4. The data show a continu-ous increase in steps completed. Following interven-tion. Lori was able to be in the bathroom stall while thetoilet was flushed repeatedly. Furthermore, Lori's com-fort with the toilet flushing was maintained during fol-low-up probes taken 1, 8. and 15 days after completingtreatment.

In the lower-left graph, baseline data show that Ja-mie failed to reach criterion levels of eomfort at step 12(animal noise toy is played repeatedly), and sessions

were terminated due to behaviors indicating that theanimal noise toy was an intolerable stimulus for him.Steps implemented during treatment, however, reacheda stable level of comfort in each session. All 12 stepswere completed during week 1. Jamie's comfort withthe animal noises was maintained during follow-upprobes taken 1, 2, and 6 weeks after intervention wascompleted.

In the bottom-right graph, baseline data indicate thatJeff failed to reaeh criterion levels of comfort at step 0(vacuum is mentioned prior to being used) and step 14(vacuum is turned on and in sight), and sessions wereterminated due to behaviors indicating that the vacuumwas intolerable for him. In contrast, steps completedduring treatment reached a stable level of comfort ineach session. Completed steps per week ranged fromone to seven: step 1 was completed during week 6. step2 during week 7, steps 2 through 8 during week 8, steps9 through 13 during week 9, and step 14 during weeks10 and 11. The data show a continuous increase in stepscompleted. Following intervention, Jeff was able toplay comfortably with the vacuum nearby, turned on,and in sight. Furthermore. Jeff's comfort with thevacuum was maintained during a follow-up probe taken3 weeks after completing intervention. Figure 2presents the number of hierarchical steps Jeff com-

Baseline Follow* up

"MoMo

u

2 0 -18 -

16-

1 4 -

1 2 -

10 -

8 —

6 -4 -

2-

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Weeks

Figure 3. Number of steps in the systematic desensitization hierarchy completed as comforiabit; per session and per week for thevacuum, blender, and hand-mixer for Child 3 (Jeff) presented in a multiple baseline across slimuli design.

Using n SyMcmatic Dtsensilizalion Paradigm 129

pleted per week during baseline, intervention, and fol-Inw-up conditions across auditory stimuli in a multiplebaseline. In the bottom graph, baseline data show thatJeff failed to reach criterion levels of comfort at step 20(Jeff goes to Blenders while juice/smoothies are beingmade), and sessions were terminated due to behaviorsindicating that the blender was an intolerable stimulusfor him. Additionally, a single baseline point indicatesthat Jeff failed to reach criterion levels of comfort atstep 14 for the hand-mixer (hand-mixer is turned onand in sight), and the session was terminated due tobehaviors indicating that the hand-mixer was yet an-other intolerable stimulus. Data collected during inter-vention showed that Jeff reached a stable level of com-fort at each step in the desensitization hierarchy. Com-pleted steps for the blender ranged from one to eightsteps per week: steps 1 and 2 were completed duringweek 18. steps 3 through 10 during week 19. steps 10through 14 during week 20, step 14 during week 23.steps 15 through 17 during week 24, and step 18 duringweek 25. Generalization probes during week 23 dem-onstrated that Jeffs comfort with the blender at homedid not generalize to Blenders, so the session was ter-minated. Thus, additional steps (steps 15 through 19)were created and implemented. These additional stepsled to generalization at Blenders (steps 19 and 20) dur-ing follow-up probes taken 4 weeks after completingintervention. The bottom graph of Figure 2 also showsgeneralization probes taken to evaluate Jeffs reactionto the hand-mixer during week 32. Without interven-tion for the hand-mixer. Jeff reached criterion levels ofcomfort at step 14 (hand-mixer is turned on in the sameroom and in Jeffs sight), thereby demonstrating gen-eralization. Additional probes were taken during week33 and 34, in whieh Jeff again reached criterion levels ofcomfort with the hand-mixer turned on and in sight.

Figure 3 presents Lori and Jamie's mean level ofanxiety observed during the increasing hierarchical stepfor the toilet flushing and animal noises, respectively.

In the top graph, baseline probes indicate that toiletflushing caused observers to judge that the toilet was anintolerable stimulus for Lori. Sessions on both dayswere terminated because of her severe reaction to thetoilet flushing. During intervention, anxiety levels de-creased from mild anxiety to comfortable and remainedrelatively stable in the comfortable range followingcompletion of steps 1 and 2. The number of intervals toreach criterion for a step completed as comfortableranged from four to nine. During the first day of inter-vention, step 1 was used and Lori's anxiety was judgedto be in the comfortable range for four 3-minute inter-vals, meeting the criterion to advance to the next step.In step 2. however. Lori's anxiety was initially judged asmild for one interval before reducing to comfortable forthe next seven intervals, thereby reaching criterion.Lori was able to move from steps 3 through 7 on thesame day, and her anxiety was reliably observed as

comfortable. On day 2 of intervention. Lori's anxietywas judged to be comfortable in steps 8 through 10. Instep 11. her anxiety was initially judged to be mild lorone interval before again reducing to comfortable forthe next seven intervals. Observers continued to judgeLori as comfortable during steps 12 and 13. therebycompleting the hierarchy. Step 13 was repeated at fol-low-up during days 5. 12. and 19. and Lori again wasobserved to be comfortable, remaining stable for fourconsecutive intervals on each day.

In the bottom graph, baseline probes indicate thatthe Mattel "See and Say" animal noises toy caused ob-servers to judge that the toy was an intolerable stimulusfor Jamie. Sessions were terminated because of his se-vere reaction to the noise. During intervention, anxietylevels were judged in the comfortable range and re-mained relatively stable. The number of intervals toreach criterion for a step completed as comfortableranged from two to nine. During week 1. step 1 wasused and Jamie's anxiety was judged to be in the com-fortable range for two intervals, meeting the criterionto advance to the next step. In step 2. Jamie's anxietywas initially judged as mild for one interval before re-ducing to comfortable for the next eight intervals,thereby reaching criterion. Jamie was then able tomove from steps 3 through 12 during the rest of week 1,and his anxiety was reliably observed as comfortable.Step 12 was repeated at follow-up during weeks 2, 4.and 7. and Jamie again was observed to be comfortable,remaining stable for four consecutive intervals on eachday.

Figure 4 presents Jeff's mean level of anxiety—ranging from comfortable to intolerable—observedduring the increasing hierarchical steps for the vacuum,blender, and hand-mixer. In the upper-left tier of thetop graph, baseline probes indicate that both mention-ing the vacuum and turning it on caused observers tojudge that the vacuum was an intolerable stimulus forJeff. During the first baseline probe, mention of thevacuum produced behaviors suggesting that it was anintolerable stimulus, and the session was terminated.The second baseline probe shows Jeff's intolerancewith the vacuum when it was turned on; thus, the ses-sion was again terminated. Finally, the vacuum wasmentioned once more during the third baseline probe,and the session was terminated following stable levelsof behavior again suggesting to observers that it was anintolerable stimulus. During intervention, anxiety levelsdecreased from high anxiety to mild anxiety to com-fortable and remained relatively stable in the comfort-able range following completion of step 2. The numberof intervals to reach criterion for a step completed ascomfortable ranged from 2 to 34. During week 6, step 1was used and Jeffs anxiety initially was judged to behigh for six consecutive intervals. His anxiety reducedto mild for the next four intervals before reducing againto comfortable and reaching criterion for the final four

130 Kocgel el al.

tn Tolerable

High Anviely

Mild Anijely

Comfortable

Toilet (lush(Lori)

InWlerable 3 ~

High Aniiely 2 ~

Mild AnsicLy ] -

Coinfortable 0 '

Animal noises(Jamie)

[nrolerable

-ligh Anniely

Mild Anxieiy

Comfonablc

3 -2 -1 -0 -

Consecutive 3-minute intervals

'Criierion for a sicp completed is 2-4 conseculivcthree-minute intervals scored as comfortable

Figure ;̂ . Mean level of iinxiety per 3-raiiiutt interval in each hierarchical step for toilet flush for Child 1 (Lori) and animal noisesfor Child 2 (Jamie).

intervals. Jeff was able to move up to step 2 duringweek 7, and his anxiety was reliably observed as low.with the exception of an increase to high anxiety duringtwo intervals. Criterion was not met for step 2 duringweek 7: thus, this step was rcintroduced during week 8until criterion was met after four consecutive intervalswere judged as comfortable. Jeff's behavior was ob-served to be comfortable during both intervals of step 3

and in the low anxiety to comfortable range during step4. Levels of comfort remained stable through the rest ofthe intervals in steps 5 through 8. Observers continuedto judge Jeff as comfortable during steps 9 through 12the following week. In step 13, his anxiety was initiallyjudged to move in and out of the comfortable rangebefore remaining comfortable for the final five inter-vals. Jeff completed step 14 (vacuum is turned on. in

Using ii Sysiemalic Descnsilizalion Paradigm 131

Intolerable 3-1

High Anxiety 2 ~

Mild Anxiety 1 -

Comfortable 0OOCT-O—inr .̂ TTu-nor--ooOsCi — ' M T t i ' i ^ f

1

High Atixieiy

Mild Anxiely

3 -

2 -

1-

0 - - • ' • ' • ' • • ' • ' • ' • • ' • ' • ' • • ' • ' • • ' • ' • • ' • • ' • ' • ' • • ' • - • r i i

Vacuum

Iiitolerabit

^lgh Anxiety

Mild Anxicly

Comfurlable

3 -

2 -

1 -

0 - • - • - • - • ' • -

Intulcrabic

High Anxieiy

Mild Aniiely

Comfortable

J 1 J I J U L

Inlokrable 3 —

High Anxiely ? "

Mild Aniieiy 1 -

Comfortable 0

Hand-mixer

Consecutive 3-minute intervals"Criterion for a sWp completed is 2-4 consecutive

three-minute inter/als scored as comfortable

Figure 4. Mean level of anxiciy pur 3-minulc interval in each hierarchical step for Ihc vacuum, blender, and hand-mixer for Child

3 (Jeff).

132 Koegcl el al.

sight, and in the same room) during weeks 10 and 11.Step 14 was repeated at follow-up, and Jeff again wasobserved to he comfortable and remained stable forfive consecutive intervals. In the upper-left tier of themiddle graph, baseline probes show that going toBlenders (step 20) elicited behaviors suggesting that theblender was an intolerable stimulus, and the sessionwas terminated. Following intervention of the vaeuumduring week 11, a second probe taken at Blenders (step20) was taken for generalization and indicated that go-ing to Blenders eontinued to produce behaviors thatsuggested the blender was causing high anxiety, and thesession was again terminated. During intervention,anxiety levels decreased from intolerable to high, thento mild, before remaining relatively stable in the com-fortable range. The number of intervals to reach crite-rion for a step completed as comfortable ranged from 2to 11. Observers judged Jeff to remain in the comfort-able range for steps 1 through 9. During week 19. Jeffwas observed to be comfortable for three intervals ofstep 10 before he was judged to have mild anxiety forone interval. Although Jeff quickly returned to thecomfortable range for the following two intervals, step10 was repeated during week 20. His anxiety initiallywas judged to be mild for one interval before reducingto comfortable and reaching criterion for the final fourintervals of step 10. Observers judged Jeff to be com-fortable throughout step 11 and then to demonstratelow levels of anxiety during Ihe first interval of step 12before returning to comfortable for six consecutive in-tervals. Thus. Jeff was systematically advanced to steps13 and 14. Step 14 was repeated during week 23, and hisanxiety was initially judged to move in and out of thecomfortable range before remaining comfortable forthe final six intervals. A generalization probe was thentaken at Blenders in which judges observed Jeffs be-havior to be in the high anxiety range. Thus, steps 15through 19 were implemented to more closely simulateBlenders. During step 15. Jeffs anxiety was initiallyjudged to be low before remaining comfortable for thefinal three intervals. Levels of comfort remained stablefor steps 17 through 19. The final test of whether gen-eral-case procedures would be effective was used atfollow-up, where step 20 (Blenders) was repeated andJeff was observed to be comfortable and remainedstable for five consecutive intervals. The bottom graphpresents the results of a further test of whether general-case procedures would produce a generalized level ofanxiety reduction to this type of auditory stimuli. Theupper-left tier of the graph shows a baseline probe in-dicating that turning on the mixer (step 14) caused ob-servers to judge that the mixer was an intolerablestimulus for Jeff, and the session was terminated. Fol-lowing intervention for the blender, a second probe ofthe mixer (step 14) was taken for generalization duringweek 32. Initially, observers judged Jeffs behavior tobe in the mild anxiety range before remaining stable in

the comfortable range for three consecutive intervals.Step 14 was used again in week 33 and week 34. inwhich observers reliably judged Jeff to remain comfort-able for four intervals. Overall, the data show that anxi-ety levels remained low throughout intervention for thevacuum and the blender and at follow-up for the hand-mixer. Thus, observers judged Jeff as comfortablethroughout much of the intervention and able to main-tain comfort in the presence of an operating vacuum,blender, and hand-mixer.

Discussion

These results suggest that the intense reactions toauditory stimuli many children with autism exhibit maybe related to a phobia rather than pain associated witha stimulus. Specifically, the extreme reactions the chil-dren displayed at baseline (running away from variousauditory stimuli, loud and severe screaming, forcefullycovering ears, sweating, shaking, and grinding teeth)might easily have suggested that the children were inpain. However, the data indicate that hypersensitivityto the sound of (he stimuli may have been a conditionedresponse that could be treated with a countercondition-ing behavioral intervention (systematic desensitization)typically used to treat phobias in children (Center,1989).

As mentioned earlier, it has been reported that manychildren with autism seem to have hypersensitive hear-ing (Grandin & Scariano. 1986; Hayes & Gordon. 1977;Ney. 1979: Rimland. 1964: Rimland & Edelson. 1995).The current study suggests that if hypersensitivity isindeed causing children with autism to display aversivereactions to auditory stimuli, then hypersensitivity ismore complex than we originally thought, yet relativelyeasy to overcome. Clinically, whether such reactionsare due to hypersensitive hearing or an unrelated pho-bia, this study suggests that children may respond fa-vorably to the same type of intervention (systematicdesensitization). Theoretically, though, if the children'sintolerant reaction to aversive auditory stimuli were en-tirely due to hypersensitivity. their responses would berelatively unchangeable with desensitization. or at leastnot likely to move into the comfortable level. The data,however, show that the responses of all three childrencould be quickly and easily modified to the point wherethey appeared completely comfortable. Following in-tervention and at follow-up, all children were reliablyrated to be comfortable in the presence of operatingauditory stimuli that at baseline appeared to be intol-erable. Thus, the children not only tolerated the sightand sound of these stimuli but also displayed behaviorsthat suggested they were comfortable (i.e., playing,smiling, laughing, and interaeting with mother or thera-pist appropriately). Again, these results indicate thateach child's initial reaction to aversive auditory stimulimay have been phobic rather than painful. Thus, the

Using a Sysiemalic Desensitizaiiim Paradigm 133

data extend reports of phobias in children wiih autism(Howlin et al.. 1973: Jackson & King. 1982: [.ove. Mat-son. & West, 1990: Luisclli. 1978) to include the ex-treme reactions they display in the presence of auditorystimuli.

Further indicating that the intense reactions to audi-tory stimuli were related to a phobia was Jeffs ability todrink a Blenders smoothie at follow-up. In describingprocedures of desensitization. Wolpe (1973) suggestedthat there were incompatible responses to fear andanxiety. In addition to relaxation and sexual arousal,digestion has been reported to be incompatible withfear. In all baseline sessions and in the generalizationprobe taken during week 23, Jeff would not drink hissmoothie, even if offered to him outside of the store orin the car on the ride home. At follow-up, however, Jeffaccepted the drink from his mother and appeared eom-fortable while consuming the entire smoothie. This ob-servation supports the finding Ihat Jell's intolerant re-action to auditory stimuli—whieh initially appeared tobe related to pain associated with the stimulus^mayhave been a conditioned response.

The exaet nature of the original conditioning, as withmost phobias, is difficult to determine. In future re-search, it might be interesting to attempt to understandwhether, or how. such conditioning occurred. One pos-sible explanation for such conditioning may be stimulusoverselectivity. a deficit in children with autism thai hasbeen validated empirically (Koegel & Wilhelm. 1973;Lovaas & Schreibman, 1971; Lovaas. Schreibman. Koe-gel. & Rehm, 1971: Reynolds. Newsom. & Lovaas.1974). In other words, children with autism often re-spond to only one component of a stimulus, whiehseems to prevent them from acquiring and generalizingbehaviors (Lovaas. Sehreibman. Koegel. & Rehm.1971), It is possible, then, that overselectivity may havecaused ihe children to attend only to auditory stimuliand prevented them from responding to other andmore relevant components of their environment. Whileyoung, typically developing children may becomefrightened by loud noises (e.g.. vacuums, blenders, andhand-mixers), auditory overselectivity may have causedthe children in this study to fail to associate the auditorystimuli with positive reinforcers. Thus, the children'sreactions to auditory stimuli may have been a condi-tioned phobic response due to their inability to respondto other stimuli in their environment.

This explanation is further supported by the inter-vention for stimulus overseleetivity: teaching responsiv-ity to multiple cues (Koegel & Schreibman, 1977:Schreibman & Koegel, 1982). Although competing re-inforcers (i.e.. small treats and snacks, toys and activi-ties, and social interaction games) were used as anxietyinhibitors, they may have simultaneously taught thechildren to respond to multiple stimuli while auditorystimuli were gradually and systematically introducedinto their environments. As each child learned to re-

spond to both the competing reinforeers and auditorystimuli, their responses to auditory stimuli may thenhave been countereonditioned. allowing them to seemcomfortable in the presence of such stimuli. This hy-pothesis also is consistent with other similar theories ofperceptual dysfunction in children with autism (Cour-chesne, Yeung-Courchesne. & Pierce. 1999; Cox &Schopler. 1993: Ritvo. 1983; Schopler, 1978; Schopler &Mesibov. 1995).

In addition to having theoretical importance, thechildren's ability to become comfortable with stimulithat were judged to be intolerable is socially significant.For example, as noted earlier, the children's reactionsto the common stimuli negatively affeeted their (andoften their family's) abilily to participate in everydaysettings. Following intervention, they were able to par-ticipate in all settings and the families did not need toavoid specific settings or alter their lifestyles because ofpossible negative effects they may have on their child.Jeff and Jamie's mothers reported that they both feltpersonal anxiety about the stimuli eausing apparentpain to the child, and that the absence of any intensereaetion related to the auditory stimulus following in-tervention had greatly improved the family's quality oflife.

Overall, the eurrent study suggests that one cause forextreme responses to auditory stimuli may be due tothe development of phobias. Thus, next steps in thistype of research might be to look at whether there aremultiple causes to children with autism's extreme reac-tions to auditory stimuli and to examine the generalityof changes. In any case, the results of the current studysuggest that a hierarchical desensitization program maybe helpful in eliminating apparent sound sensitivities inchildren with autism.

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Received: March 14. 2(KI4Final acceptance: June 30. 20(J4Editor in charge: George H. S. Singer