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1988; 68:664-671.PHYS THER.Gay M Naganuma and Felix F Billingsleyof Three Girls with Rett SyndromeEffect of Hand Splints on Stereotypic Hand Behavior

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E f f e c tofHand Sp l i n t s on S te r eot yp i c Hand B ehav ior ofTh r ee G i r l s w i th Re t t S yn d rom eG A Y M . NA G A N U M Aa n d FELIX F . BILLINGSLEY

The purpose of this mu ltiple baseline study wa s to examine the effect of bi lateralhand splints on the persistent stereotypic hand movements of three adolescentgirls with Rett syndrome. Among the most characteristic features of Rett syndrome are stereotypic hand-wringing and hand-biting behavior and loss of previously acquired functional hand ski l ls. The hand splints used in this studyconsisted of cuffs encircl ing the palm that positioned the subjects thumbs inabduct ion. Duration percentages of subjects stereotypic hand behavior andfunct ional hand use were calculated from f ive-minute v ideotaped segmentsrecorded during a finger-feeding condition and a free-time condition. All threesubjects demonstrated a decrease in the amount of t ime spent in stereotypichand behavior after application of hand splints, and one subject showed anincrease in finger-feeding ski l ls while wearing hand splints. Limitations of thestudy are discussed, and suggestions for cl inical application and future researchare offered.K e y w o r d s : Hand; Medical conditions; Orthotics/splints/casts upper extremity;Stereotyped behavior.

Rett syndrome is a progressive condition observed only ingirls and charac terized by autistic-like behavior, m ental retardation, gait apraxia, spastic increase in muscle tone, deceleration of head grow th, seizures, loss of purposeful hand skills,and stereotypic movements of the hands.1- 4 The conditionwas first described in 1966 by Viennese physician AndreasRett, and since then, about 1,000 cases of Rett syndromehave been docum ented world-wide.5Among the most characteristic clinical features of Rettsyndrome are stereotypic hand-wringing, hand-mou thing, andhand-biting behaviors that often coincide with the loss ofpreviously acquired purposeful hand skills.1,4,6 Many clinicians consider the presence of stereotypic hand behaviorsnecessary for positive diagnosis.3,7 Hagberg et al found boththe loss of purposeful hand use and hand stereotypies to bethe only items from a list of main clinical features that weremanifested in all 35 subjects with Rett syndrome they studied.1 Tissue maceration is an associated complication ofstereotypic hand behavior.1,4,8 Eighty percent of the occupational therapists and physical therapists working with patientswith Rett syndrome who responded to a preliminary questionnaire prepared by physical therapists at The University ofWashington Child Development and Mental Retardation

Center reported that the hand use of their patients was anarea of primary concern (D. Brady, T. Crowe, G. M. Nagan-uma, K. Stewart; unpublished data; 1985).Traditional behavior m anagement techniques have generally been ineffective in producing consistent changes in subjects with stereotypic hand behavior. Zapella produced nochange in the stereotypic behavior of girls with Rett syndrom ewhen he used a low intrusion method (ie, interacting with thechild in a stimulating, joyful manner) described for autisticchildren.9 The incessant hand kneading and rubbing of a 2-year-old girl could not be interrupted during a case studyreported by Kulz et al.10Nomu ra et al noted anecdotally thatattempts to modify stereotypic hand behavior using bothpsychological means and various drugs have been unsuccessful.6In a recent study, however, Iwata et al reduced the hand-biting behavior of two girls with Rett syndrome using differential reinforcement combined with a response-interruptiontechnique.8During baseline sessions, the subjects' hand- bitingbehaviorwas ignored and verbal praisewasprovided for hand-to-toy contact. During the intervention phase, the subjects'compliance with an instructional task and hand-to-toy c ontactwere reinforced with verbal praise and small pieces of apreferred snack. Contingent on the occurrence of hand-bitingbehavior, the experimenter held the subjects' hands in astationa ry position for a 30-second (Subject 1) or 10-second(Subject 2) interval before resuming the activity. In additionto reductions in the hand-biting behaviors of both subjects,increases in hand-to-toy contact were observed to coincidewith decreases in hand-biting behav ior for one of the subjects.Such results are consistent with earlier findings in whichincreases in various desirable behaviors have been shown tooccur with decreases in stereotypic behaviors.11,12

We examined the use of bilateral hand splints as an alternative strategy to operant methods for reducing stereotypichand behavior in individuals with Rett syndrome. Operant

G. Nag anum a, MS , is Staff Physical Therapist, Boyer Children's Clinic, 1850Boyer Ave E, Seattle, WA 98112 (USA). She was a graduate student, Department of Rehabilitation Medicine, The University of Washington, Seattle, WA,when this study was conducted.F . Billingsley, PhD , is Professor, Area of Special Education, T he U niversityof Washington, WJ-10, Seattle, WA 98195.This research was funded by the Research Trust Fund of the WashingtonAssociation for Retarded Citizens.This study was completed in p artial fulfillment ofthe requirements for Ms.Naga num a's Master of Science degree, Department of Rehabilitation M edicine,The University of Washington.This articlew as submitted August 31 1987; was with the auth ors forrevisionfour weeks; and wasaccepted November25 1987. Potential onflict of Inter-est: 4.

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RESE RCHconditioning requires the presence of a behavior managerwith the child to provide intervention. Iwata et al did notindicate whether th e reduction in hand-biting behavior couldbe generalized to situations where the childwasnot monitoredby a manager.8 The use of hand splints, should they proveeffective, would be advantageous because the child couldexperience the benefits of intervention independent of a man ager. In add ition to cost effectiveness, th e use of hand splintshas the potential advantage of allowing classroom staff tospend more time in instructional programs rather than inresponse-interruption programs.Hand splints have been reported clinically to decrease thefrequency of stereotypic hand behaviors in girls with Rettsyndrome, but no systematic examination of this treatmentstrategy has yet been completed. Han ks com mented that

splinting is found to be successful in interrupting hand-to-mouth, and to a lesser degree, hand-wringing [behavior], thusallowing the girls to direct their attention outward to noticetoys and people rather than having their attention totallydominated by their hand wringing.13(p250)Because hand splints could potentially reduce stereotypichand behavior and influence the ability of girls with Rett

syndrome to interact with their environment, this multiplebaseline study explored the effect of hand splints on thestereotypic hand behavior of three girls with Rett syndrome.An additional purpose of this study, based on the findingsof Iwata et al8 and others,11,12 was to examine whether anincrease in the subjects' purposeful hand usage would coincidewith or follow the reduction of stereotypic hand behavior. AsHa nks stated, Indeed , observation makes it fairly evidentthat the girls would like to do something else with their handsbut can not break through the hand w ringing to doso. 13(p250)

METHODS u b j e c t s

The three subjects were enrolled five days a week in aspecial education program for students with severe or profound ha ndicaps at a university-affiliated cam pus school. Thesubjects attended school 5.5 hours a day, and in addition totheir regular classroom program, they were treated by a communication disorders specialist, a physical therapist, and anoccupational therapist. Subject B attended school 4.5 hours aday during the first half of the study because of specialtransportation needs. Written informed consent was obtainedfrom a parent of each subject.All three subjects were diagnosed with Rett syndrome atthe Child Developm ent and M ental Retardation Center. Subject B was diagnosed with Rett syndrome in 1983 at the ageof 13 years, one of the earliest cases of Rett syndrome diagnosed in the United States. Subjects A and C were diagnosedwith Rett syndrome in 1984 at 11 and 14 years of age,respectively.Subject A was a 13-year-old girl whose stereotypic handbehaviors began a t 15 mo nths of age. Before this study began,her han d behaviors consisted of bilateral pill-rolling mo tions of her fingers against her thumb and palm and gentleclapping motions of her fists. Subject A had worn a restinghand splint occasionally to maintain left wrist extension, butbecause her wrist range of motion was measured withinnormal limits, use ofthissplint was discontinued during thisstudy. Subject A's previous levels of functional h and use werevery limited. She could hold a straw to her mouth after it had

been placed in her hand, and she was learning to reach withher right hand to grasp a small piece of food held in front ofher at eye level. Subject A did n ot use these functional skillsconsistently.Subject was a 16-year-old girl who began showing stereotypic hand behavior at about 2 years of age. At the start ofthis study, her hand movements consisted of slow repetitivehand-wringing, hand-clapping with flexed fingers, and hand-mouthing behaviors. Subject B had never worn an upperextremity orthosis for reduction of stereotypic hand behavioror any other reason. Before intervention, Subject B couldfinger feed herself independen tly but w as laboriously slow (eg,she took ab out on e hour to eat a sandwich and piece of fruit).She could also activate simple switches by hand .Subject C was also 16 years old and began showing stereotypic hand m ovem ents at about 1 year of age. Before thisstudybegan,her han d movements consisted of repetitive handwringing with her hands together, bilateral hand squeezingwith her hands apart, and hand-mou thing behaviors. SubjectC had previously been fitted with a unilateral hand splint,similar in design to the splints used in this study, but its usewas discontinued three months before this study began because the splint was ineffective in reducing stereotypic handmovements. Bilateral splinting may have been necessary toreduce the subject's stereotypic hand movements. Subject C'sprevious levels of functional hand use were limited to graspingthe handles ofawheeled walker and occasionally reaching tograsp an object held in front of her at eye level.Mate r i a l s

Three pairs of thumb abduction splints were fabricated byan occupa tional therapist experienced in splinting techniques.The splints were constructed of Polyformsplinting material.*This material was used because it is thin, smooth, and rigidbut very moldable when heated. Because the splints werefitted to accommodate the contours of three different pairs ofhands,they were slight variations of abasicdesign.The splintsresembled a cuff circling each palm and positioned the thumbout ofthepalm into abduction (Fig. 1). The splints restrictedexcessive opposition of the thumb across the palm but didnot functionally restrict the subject's grasp or movements ofthe fingers and wrist. Wearing time was gradually increaseduntil the subjects wore the splints every school day from 9AM to 2:30 PM.R e s p o n s e De f in i t io n s

Stereotypich andbehaviorwas defined as 1) hands in contact with each other and moving in any way (washing, wringing, or clapping movem ents), 2) hands no t in contact bu t oneor both hands engaged in a repetitive squeezing or pill-rollingmotion, or 3) one or both hands in contact with the subject'slips or tongue unless the subject was putting a piece of foodinto her mouth. One hand could be resting quietly as long asthe other hand fit one of the above criteria. Behavior ceasedto be considered stereotypic if both hands discontinued themovements described above or if both hands were motionlessfor more than two seconds.Functional hand use was defined as the subject's handcontacting a piece of food and moving toward the subject'smouth. The definition excluded time when the subject held

* Rolyan Medical Products, PO Box 555, Menomonee Falls, WI 53051.Volume 68 / Number5 May 1988 665

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F ig .1. Ba s i c h and sp l i n t d e s ign : a) do r sa l v iew a nd b ) p a lma r v i ew .

food but ceased to bring it toward her mouth for more thantwo seconds. As long as the subject had one hand in theprocess of grasping a piece of food, bringing it to her mouth,or placing it into her mouth, functional hand use would bescored, even if the subject's other h and was engaged in stereotypic hand movement.The definitions for stereotypic hand behavior and functional hand use were exclusive. Both conditions could notoccur at the same time. In addition, periods of time couldexist when the subjects' behavior would not fit either of the

two conditions (eg, when the subject's hand had left her m outhbut had not yet resumed stereotypic movements or picked upanother piece of food).E x p e r i m e n t a l De s i g n an d P h a s e s

This study used a multiple-baseline, across-subjects design.During baseline phases, subjects did not wear hand splintsand could initiate functional hand use or perform stereotypicmovements as they preferred while in the classroom. Duringintervention phases, subjects wore a splint on both hands forincreasingly longer periods of time. As during the baselinephases, hand behaviors (stereotypic or functional) duringintervention phases were not interrupted nor was any attem ptmade to reinforce them. A brief withdrawal phase (return tobaseline condition) was conducted for all subjects at thecompletion of the study to identify any maintenance effectsof the hand splints. Subjects did not wear their hand splintsduring the withdrawal phase and could perform whateverhand behavior they preferred.In keeping with multiple-baseline design requirements,hand splints were applied in a sequential fashion to eachsubject only after stability on a behavioral level or a trend wasestablished. After 15 days of the baseline con dition, SubjectA began wearing her splints. Baseline data continued to becollected for the other two subjects. Wearing tim e for SubjectA was gradually increased over the next nine days. The rateof increase for all subjects was determined by skin tolerance.The appearance of red marks that did not fade within 15minutes after splint removal resulted in smaller incrementsof increased wearing time. On Day 29 of the study, the handsplints wereintroduced to SubjectB.Wearing time for SubjectB was increased over the next four days. Baseline conditionscontinued for Subject C, and on Day 43 she began wearinghand splints. Wearing time for Subject C was gradually increased over the next seven days. Fifty-four days after the startof the study, all three subjects were wearing hand splints theentire time they were at school. The subjects' spring vacationcoincided w ith D ays 59 to 73, and during this period, n oneof the subjects wore their splints. This withdrawal phasecontinued during their first week back at school (Days 74-78).The subjects began wearing their splints again during th esecond week after spring vacation. The withdrawal phase forSubject B began before spring vacation on Day 55. Herwithdrawal phase began early so that we could obtain enoughdata to establish internal validity for functional hand use.Data Co l l ec t ion

Videotapes were recorded during the afternoon of eachschool day with each subject seated at a table in a quiet partof the classroom with minimal visual distractions (eg, fewindividuals moving about within the subject's visualfield .Adish containing pieces of a cracker was placed on the tabledirectly in front ofthesubject within easy reach. The subjectwaspositioned w ith both up per extremities above the tabletopso that both hands were visible to the camera at all times. Noinstructions or prompts were provided so that subjects wouldindependently initiate and maintain any hand behavior,whether stereotypic or functional. Each videotaping sessionlasted five minutes. The use of a video recorder enableddurations of stereotypic and functional behavior to be timedseparately with a digital stopwatch and thus eliminated the



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RESE RCHneed for the investigator to simultaneously measure two behaviors during direct observation.Duration of stereotypic m ovements also was recorded during a five-minute free-time period just before the finger -feeding condition where the subject was seated in a chairlistening to music through headphones. Duration measureme nts were taken from videotapes recorded three days a week(Tuesday, Thursday, and Friday). The free-time conditionprovided an o ppor tunity to exam ine any differential effectsof the hand splints specific to the demands of the situationfor production of functional hand use. The furniture, materials, and positioning of subjects and equipment were keptconstant through out all of the d ata collection sessions and theintervention phase. Subjects wore their hand splints duringeach data collection session.Re l i ab i l i t y

Interobserver agreement Interobserver agreement was assessed everyfifthday of data collection with one of the au thors(G.M.N.) as the primary observer and the subjects' occupational therapist as the second observer. The observers simultaneously viewed each videotaped segment but were positioned in the room so that they could neither see nor hearhow the other observer was scoring the videotaped segment.Neither observer was blind to the purpose of the study.Percentages of interrater agreement were calculated for allduration conditions (stereotypic movement during presentation of food, functional hand use, and stereotypic movementduring free time) for all three subjects using the followingformula:

S S / S L 100where S sis the smaller oftwoobservers' scores and SLis thelarger of the two observer's scores. Percentages of interrateragreement for stereotypic movement during presentation offood ranged from 67% to 100% ( = 92.5% ). Scores fellbelow 80% on 2 of 27 occasions (7.4%). Percentages ofinterrater agreement for functional hand use ranged from90% to99%( = 95.6%). Percentages of interrater agreementfor stereotypic movement during free time ranged from 64%to 99%( =9 1% ). Scores fell below80%on 4 of 27 occasions(14.8%).Point-by-point agreement14 was also calculated every fivedata collection days using the same videotaped sessions thatwere used to calculate percentages of interrater agreement.This method of assessing interrater reliability was used inaddition to percentages of interrater agreement because percentages of interrater agreem ent reflect only agreement on th etotal amo unt of behavior observed, not whether the observersagreed on any particular instance of performance. Each 5-min ute session was divided into 10-second intervals, and eachobserver scored whether stereotypic behavior or functionalhand use, or neither, had occurred at the en d of each interval.Point-by-point agreement was calculated by dividing thenumber of agreements by the number of intervals and multiplying the quotient by 100. Point-by-point reliability scoresranged from 84% to 100% ( = 93.9%)Procedural reliability Procedural reliability was assessedduring all phases of the investigation.15This process was usedto examine the reliability with which experimental procedureswere followed. The classroom teacher assessed the experimental environmen t weekly to d etermine whether it was set up ina consistent manner. The data collector was unaware of

monitoring occasions. A check list of setup requirements wasprovided for the classroom teacher to determine consistency(eg, proper placement of the video camera in relation to thesubject, both of the subject's upper extremities visible to thecamera, subject listening to music through audio headphonesduring the free-time condition). The experimental environment was reproduced correctly on all monitoring occasions.Wearing time of the hand splints for all subjects was alsomonitored to ensure appropriate use. Actual wearing timewas monitored daily and was consistent with the establishedwearing schedule on93%,95% , and 92% ofthe interventiondays for Subjects, A, B, and C, respectively. Actual wearingtime ondaysthatwereinconsistent with the schedule deviatedby an average of 1.6 ho urs.RESULTSS t e r e ot y p i c H a n d B e h a v i or

The data for stereotypic hand behavior of the three subjectsduring the feeding condition are shown in Figure 2. Thepercentage of time Subject A spent performing stereotypichand movements during baseline sessions remained fairlystable from day to day ( = 69.8% ). The hand splints wereintroduced on Day 16, and during the intervention phase,Subject A demonstrated a slow, gradual decrease in stereotypic hand beh avior. During the last five days of the interve ntion phase, her mean level of stereotypic hand behavior haddecreased to 37.2%. The mean duration of stereotypic handbehavior for the entire intervention phase was45.8%.Duringthe second baseline (withdrawal) phase that followed the 15-day spring vacation, Subject A's stereotypic behavior re turnedto a level higher than the original baseline level ( = 7 9 % ).Three data collection sessions had been plann ed forthisphase,but data on one of those sessions was not obtained becauseof Subject A's unusually ex treme sleepiness.The stereotypic behavior of Subject B during the baselinephase was fairly stable with no change in trend when handsplints were introduced for Subject A. The mean duration ofstereotypic hand behavior for Subject B during the baselinephase was 54.9%. After application of the hand splints onDay 29, she displayed an immediate and marked decrease instereotypies ( = 6.2%). Durin g the baseline phase, SubjectB would frequently resume stereotypic hand movements between each bite of food. During the intervention phase, sheonly occasionally engaged in stereotypic hand movementsbetween bites, and her hands tended to rest quietly, or sheattemptedtopick up anoth er piece of food. During th e secondbaseline phase, her stereotypic hand behavior immediatelyincreased to a mean level beyond that achieved during theoriginal baseline phase (based on data points both before andafter spring vacation; =6 9.7 % ).The baseline data for Subject C were quite variable but didnot display any particular trend and did not appear to beaffected by the introduction of hand splints to Subject A orSubject B. Subject C's mean duration of stereotypic handbehavior during the baseline phase was 62.2%. After application of her hand splints on Day43,Subject C also displayedan immediate decrease in hand movements with a meanduration of 13.7% during the intervention phase. Despite theconsiderable variability in Subject C's baseline phase data,only two of the baseline data points ov erlapped into the ran geof the intervention phase data. During the withdrawal phaseafter the spring vacation, Subject C's stereotypic hand behav-

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F ig . 2. Sub je c t s ' s t e r eo t yp i c h and m ovemen t s d u r ing t h e f e e d ing p rog ram . (Dura ti on = p e r cen t age o f time r e sponse occu r r ed du r i ng d a t acol lect ion in terva l.)ior returned to near-baseline levels ( =4 4.3 % ). No overlapof data points existed between the intervention phase and thesecond baseline phase.Figure 3 illustrates the stereotypic hand behavior of thethree subjects during the free-time condition. Subject A demonstrated an upw ard trend in stereotypic hand behavior during the baseline phase ( = 7 5.8%). As in the feeding condition, she responded to the application of her hand splints witha slow, gradual decrease in stereotypic hand behavior. Duringthe last five days ofthe intervention phase, her mean level ofstereotypic hand behavior had decreased to 30%. The mean

duration of stereotypic hand movements during the entireintervention phase was 48.1%. Levels of stereotypic handbehavior during the second baseline phase exceeded the original baseline level ( = 84% ). The hand splints appeared tohave no substantial differential effects depen dent on the con ditions of the environment (feeding or free time) for SubjectA. The levels of stereotypic hand behavior emitted throughall phases of the free-time condition were slightly higher th anthe levels in corresponding phases of the feeding co ndition.Subject B showed very stable day-to-day behavior duringthe baseline phase ( = 77.4%). She displayed an imm ediate



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F ig . 3. Sub jects stereotypic hand movem ents during free time. (Duration = percentage of time response occurred during data collectioninterval.)

decrease in stereotypic hand behavior after introduction ofhand splints during the intervention phase ( = 20.4%). Thewithdrawal phase brought an increase in stereotypic behaviorshigher than th e original baseline level ( = 87.2% ). As withSubject A, the only noticeable difference between the feedingand free-time conditions for Subject appeared to be slightlyelevated levels of stereotypic hand behavior during all phasesof the free-time condition.The stereotypic hand behavior of Subject C was quitevariable during the baseline phase ofthe free-time condition.No apparent trend or change in the data, however, occurredwith introduction of hand splints to Subjects A and B. The

mean duration of stereotypic hand behavior during the baseline phase was 68.4%. During the intervention phase, SubjectC exhibited an immediate decrease in stereotypic hand movemen t ( = 18.4%). Despite the variability of the data in thebaseline phase, data points did not overlap between the baseline and intervention phases. The withdrawal phase demonstrated an increase in the level of stereotypic hand behaviortoward the original baseline level ( = 37 % ). One data pointfrom the second baseline phase overlapped the range of datapoints from the previous phase. As with the other subjects,no difference in hand splint effectiveness existed between thefeeding and free-timeco nditions. SubjectCdid display slightly

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elevated levels of stereotypic hand behavior during the firstbaseline and intervention phases ofthefree-time condition.Fu n c t i on a l H a n d Us e

Before introduction of the hand splints, Subject A andSubject C did not use finger-feeding skills. Subject B couldfinger feed herself independently but very slowly. Subjects Aand C did not initiate independent finger feeding after application of the splints, although their hand behavior duringintervention phases was no longer dominated by stereotypichand movements. Subject B, however, did demonstrate animmediate increase in finger feeding after introduction of thehand splints. Figure 4 contains the data for the functionalhand use of Subject B. The mean duration of finger feedingof Subject B during the baseline phase was 31.8%. Theoccurrence of finger feeding increased dramatically after introduction of the splints on Day 2 9. During the interventionphase, the mean du ration of functional hand use increased to66.6%. The amount of time Subject B required to eat asandwich and piece of fruit decreased from about 60 minutesto about 45 minutes. The extreme data point correspondingto Day 51 was very atypical of Subject B's behavior. Sheappeared to be ill and ate nothing the entire school day. Afterremoval of the hand splints, the duration of finger feeding inSubject B during the second baseline phase returned almostto her original baseline level ( = 23.3%).DISCUSSION

A decrease in stereotypic hand behavior occurred in allthree subjects after the application of hand splints; for two ofthe subjects, the effect was both immediate and substantial.This repeated dem onstration of the target behavior changingin response to (and not before) application of the interventionmakes the influence of extraneous variables implausible. Inaddition to demonstrating an absence of any lasting effectafter removal of the hand splints, the withdrawal phase conducted with each subject provided a second baseline condition. Data obtained in that baseline condition strengthened

the internal validity of the investigation, because the stereotypic hand behavior of each subject and the functional handuse of Subject returned to levels near those achieved duringthe original baseline phase.The results of this study were consistent with the findingsof Iwata et al in successfully reducing stereotypic hand behaviors ingirlswith Rett syndrome.8Although Iw ata et al isolatedhand-biting behavior as the target of intervention8 and ourstudy examined combinations of hand-biting and hand-wringing behaviors, both studies demonstrated that these behaviorscan be reduced substantially.In addition to significantly reducing stereotypic hand behavior, the hand splintswereeffective in improving the finger-feeding skills (functional hand use) of SubjectB.She engagedin finger feeding more frequently and required less time tofeed herself after application of the splints. After splint application, Subject B's finger feeding was no longer interruptedby constant stereotypic hand movements. The stereotypichand beh aviors had possibly been functioning as a competingbehavior to purposeful han duse.This result is consistent withthe findings of Iwata et al8 and Bierly and Billingsley11 thatshowed an increase in appropriate behavior concurrent withreductions in stereotypic hand behavior.Hand splints, however, did not produce finger feeding inthe two subjects who did not possess finger-feeding skillsbefore this study. Subjective observations by the classroomteacher and the occupational therapist indicated that SubjectA's ability to grasp a piece of food held in front of her at eyelevel and bring it to her mouth and her ability to grasp aspoon, scoop food onto it, and bring it to her mouth didimprove after application of the splints. Because these skillswere part ofa classroom program, whether instruction or thehand splints caused the reported behavior change is unclear.By decreasing the amount of time the subject spent in stereotypic hand behavior, a state more conducive to learning andpractice may have been created. Future investigations shouldexplore whether individuals with Rett syndrome can learnfunctional hand skills more readily when their stereotypichand behaviors are reduced with hand splints.

F ig . 4. Functional hand use of Subject B. (Duration = percentage of time response occurred during data collection interval.)670 PHYSICAL THERAPY

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RESE RCHNo substantial differential effects of the han d splints specificto the degree of opportunity presented by the environmentfor production of functional hand use existed. The pattern ofresponse to hand splint application was similar for both thefeeding an d free-time cond itions. In all three subjects, a slightelevation occurred in the levels of stereotypic hand behaviorduring the free-time condition compared with the feedingcondition. The subjects could have spent more time engagedin stereotypic hand behavior when no activity deman ds wereplaced on their hands, bu t this study did not clearly dem onstrate that conclusion.L i m i t a t i o n s

One lim itation of this study is the possible expectation biasintroduced by the primary data collector and the secondobserver. Neither individual was blind to the purpose of thestudy. Interrater reliability could be strengthened by havingvideotaped segments viewed and scored by raters who areblind to the purpose of the study and to which baseline phasethe subject was in. The use of such procedures obviously isdifficult w hen the presence or absence of the treatme nt device(eg, hand splints) is obvious to the viewer. An additionallimitation of the study is a possible reduction in the degree towhich the results can be generalized to an average classroomenvironment. W e used a quiet part of the classroom that wasnot typical of the usual activity level of that room. Theeffectiveness of hand splints may be affected by the amountof distractions in the environme nt.Im p l i c a t i o n s f or Fu t u r e R e s e a r c h

The me chanism by which hand splints influence stereotypichand movements is unknown. Hand movements may createa type of sensory input required by individuals with Rettsyndrome, and hand splints may provide that input or alterthe need for that input in some way. Another possible explanationwasderived from a technique used in the re habilitationof patientswhohave experienced an upper m otoneuron lesionand display synergistic patterns of muscle spasticity. Theposition of thumb abduction provided by the h and splints issimilar to the reflex-inhibiting posture described by Bobath 16and the thumb maneuver described by Brunnstrom.17 Thethum b position reverses a com ponent of the total synergy ofmovement (elbow flexion, wrist flexion, and adduction of thefingers and thum b) and thus creates a relaxation of the totalsynergy. Elongation of shortened muscle groups or joint proprioception, or a combination of both, may inhibit this movement pattern. Future researchers should attempt to identifywhich characteristic of the splints or process resulting from

splint application is responsible for the reduction of stereotypic hand movements.Future researchers should also investigate whether procedures could be implemented that might allow subjects todiscontinue use of hand splints. This study demonstrated nomaintenance effects of hand splints over time; however, agradual reduction in hand splint wearing time, compared withan abrupt termination, could promote a more enduring outcome. Future studies could also assess hand-wringing andhand-mouthing behaviors separately. We noted subjectivelythat the hand splints used in this study appeared to reducepill-rolling and hand-wringing behaviors to a greater extentthan hand-mouthing and hand-clapping movements. Futurestudies could assess these differences objectively.C O N C L U S I O N

The results of this study suggest that the use of han d splintscan successfully reduce stereotypic hand behaviors in girlswith Rett syndrome. The associated risk of skin breakdownthus can be reduced significantly. Although the functionalhand use of one subject improved after application of thesplints, children with Rett syndrome should not be expectedto begin to spontaneously demonstrate functional behaviorsthat they were unable to perform before hand splinting. Handsplint application may create a behavior state that is moreconducive to learning and practicing functional hand skills.This study was possibly the first to examine the use of handsplints in girls with Rett syndrome, and the study proceduresshould be replicated to determine generality of results.1 Research based on a single-subject design relies on replication ofprocedures across settings and subject types to establish theextent to which treatment may be applied successfully toindividuals with diverse characteristics in v arious contexts.

Acknow ledgmen ts. We gratefully acknowledge the assistance of Jo Ann M cMillan, MSEd; Susan R. Harris, PhD; andSheila Fitzgerald, OTR.

Postsc ript. After com pletion of this study, an initial attemp twas made to explore the limits of generality of the hand-splinting procedure by applying hand splints to one additionalsubject who displayed stereotypic hand movements but didnot have Rett syndrome. The subject was a 9-year-old boywith severe mental retardation and tuberous sclerosis. Noeffect was observed on the subject's level of hand stereotypicbehaviorasa function of splinting; however, the subject nevertolerated hand splints for more than two hours a day. Thedata from that investigation are available from the seniorauthor (G.M.N.).REFEREN ES

1. Hagberg B , A ica rd i J , Dias K, e t a l : A p rogress ive sy nd rom e o f au t ism ,dem en t i a , a t axi a a nd loss o f pu r pose fu l h and use i n g i r ls : Re t t ' s s y n d rom e -R ep o r t o f 35 ca se s . Ann Neu rol 14 :471 -479 ,19832. Ho lm VA: Re t t ' s s ynd rome : A p rog r ess i ve d e ve lopmen ta l d i sab il it y i n g i rl s .J Dev Behav Ped ia t r 6 :32-36,19853. Le ibe r B: Re t t ' s synd rome: A noso log ica l en t i ty . Bra in Dev 7 :275-276,19854 . Re t t A : Ce reb r a l a tr oph y a ssoc i a t e d w i t h h ype r amm onaem ia . Handbookof Cl in ica l Neurology 29:305-329,19775. Sch le ichkorn J:Ret t s ynd rome: A neurolog ica l d isease la rge ly und iagnosedhere . PT Bu l le t in 2(9) :16-18,19876 . Nomu ra Y , Segawa M, Hasegawa M: Re t t s ynd rome : Cl in i ca l s tud i es a ndpa thophys ica l cons ide ra t ion . Bra in Dev 6 :475-486,19847. H agberg B, Gout ie res F, Hane f ie ld F, e t a l : Re t t syn d rome: Cr i te r ia forinc lus ion and exc lus ion . Bra in Dev 7 :372-373,19858. Iwa ta BA, Pace G M, Wi l li s KD, e t a l:Operan t s tud ies o f se l f -in jur ious handb it i ng in t h e Re t t s ynd rome . Am J Med Gene t 24 :157-166,19869. Zape l la M: R e t t sy nd rom e: A s ign i f i can t p ropor t ion o f g i rl s a f fec ted by

au t is t i c behav io r . Bra in Dev 7 :307-312,198510. Kulz J, Poh l H, Schober S: A con t ribut ion rega rd ing the R e t t ' s sy nd rom e.Bra in Dev 7 :316-319,198511 . Bie r ly C, B i ll ings ley FF: An inv est iga t ion o f the educ a t ive e f fec ts o f ove r cor rec t ion on the behav io r o f an au t is t i c c h i ld . Behav io r D isorde rs 9 : 11-21,198312. Epste in LH , Doke LA, Sa jwa j T E, e ta l:Gene r a l it y a nd s i d e e f f e c t s o f o ve r cor rec t ion . J App l B ehav Ana l 7 :385-390,197413. HanksSB :The ro le o f the rapyinRe t t s ynd rom e . Am Med Gene t 24 :247-252,198614. Kazd in AE: S ing le -Case Res ea rch Designs: Methods fo r Cl in ica l and App l ied Se t t ings . New York, NY, Oxford Un ive rs i ty Press Inc, 198215. Bi l l ings ley FF, Wh i te OR, Munson R: Procedura l r e l iabi l it y : A ra t iona le andan exam p le . Behav io ra l Assess m en t 2 :229-241,198016. Bobath B (ed) : Adu l t Hem ip leg ia : Eva lua t ion and T rea tm en t . London,Eng land , Wil l iam He inemann Med ica l Books L td , 197017. B runnst rom S: Movem en t The rapy in Hemip leg ia : A Neurophys io log ica lApproach . New York, NY, Harpe r Row , Pub l ishe rs Inc, 1970

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1988; 68:664-671.PHYS THER.Gay M Naganuma and Felix F Billingsleyof Three Girls with Rett SyndromeEffect of Hand Splints on Stereotypic Hand Behavior

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