A Study of the Clinical Test of Sensory Interaction and Balance

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Research ReportA Study of the Clinical Test of Sensory Interactionand Balance

Key Words: Balance, Equilibrium, Posture, Tests and measurements, Vestibularsystem.

Background and Purpose. The ability to maintain an upright position dun'ngquiet standing is a usefil motor skill. The Clinical Test of Sensory Interaction andBalance is an inexpensive, easily administered test that provides informationabout the ability to stand upright under several sensory conditions. Subjects.

Successful performance of some dailylife tasks, such as reading the titles ofbooks on a shelf, requires the abilityto maintain an upright position. Forthis reason, many physical therapistsare concerned with their patients'ability to perform this motor skill. Wewill refer to the ability to maintain anupright position during quiet standingas "balance." Force platforms, electro-myography, and motion analysis sys-tems have all been used for assess-

Helen CohenCathleen A BlatchlyLaurle L Gombash

ment of balance.' These sophisticatedsystems, however, are expensive andoften impractical for use by a thera-pist in a typical hospital or privatepractice. They require considerablefloor space, special training, and com-puters. These resources may be un-available to the clinician who wouldlike to be able to test patients' bal-ance, but who lacks funds to purchasesophisticated equipment or who mustcarry equipment from place to place.

Three groups of neurologically asymptomatic (AS) adults, divided by age intoyounger, middle-aged, and older groups, participated in the study.A fourth groupcomprked subjects diagnosed with vestibular disorders. M et b o d s . Timed perjor-mances under six dzrerent conditions were compared across groups. Results.Subjects with vestibular disorders were signifcantly impaired on perjormancewhen compared with age-matched AS subjects. OlderAS and vestibularly impairedsubjecrs had greater variation in their scores than did younger AS subjects. Con-cluston and Dlscussfon. This test is a usehl screening tool for examiningstatic standing balance. [CobenH, Blatchly GI, ombash LL. A study of the Clini-cal Test o f Sensory Interaction and Balance. Phys Ther. 1993;73:346354..]

H Co hen, EdD, OTR, is Assistant Professor, Department o f O torhinolaryngology and Comm unica-tive Sciences, Baylor College of Medicine, One Baylor Plaza, Houston,TX 77030 (USA). She wasAssistant Professor, Program in Rehabilitation Science, and Assistant Professor, Departrnent of Oto-laryngology, Medical College of Ohio, Toledo, OH 43699, at the time of this study. Address allcorrespondence to Dr Cohen.CA Blatchly, PT, is Assistant Professor, Program in Physical Therapy, Medical College of OhioLL Gombash, PT, is Physical Therapist, Medical College Hospital, and Clinical Lecturer, Departrnentof Otolaryngology, Medical College of Ohio .This study was approved by the Institutional Rwiew Board of the Medical College of Ohio.This article wa s submitted February 18 , 199 2, and wa s accepted January 29 , 1 993.

Therefore, a simpler, less expensivvalid, and reliable test is needed.The Clinical Test of Sensoq Interaction and Balance (CTSIB) is a timedtest that was developed for systemacally testing the influence of visual,vestibular, and somatosensoq inpustanding balance.2 This test is inexpsive, requires minimal equipment, is currently in use by some cliniciaConditions 1,2,and 3 involve standon the floor with eyes open, eyesclosed, and wearing a visualconflicdome. The dome provides a sensoconflict by depriving the subject ofperipheral vision and introducing asway-referenced image. Use of theconflict dome results in a discrepanbetween vestibular input stimulatedpostural sway and visual flow.' Thuconditions 2 and 3 should examinedifferent aspects of sensoq organiztion of visual information that may

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require different postural adjustments.3That is, condition 2 exam ines howwell subjects maintain balance in theabsence of any vision, and condition 3examines how well subjects maintainbalance wh en vision is present bu t thatinforma tion conflicts with v estibularinformation.Conditions 4, 5, and 6 involve stand-ing on foam and repeating the visualconditions described for conditions 1through 3. For each condition, thelength of time the subject can main-tain standrng and the amount of bodysway that occurs a re assessed.Although no rms fo r this test havebee n established for children andyoung adults, norms fo r performanceon the CTSIB have not been estab-lished for older adults and patientswith vestibular deficits.4.5 Currently,the CTSIB requi res perform ance of atleast on e trial on each of the six con-ditions. Some investigators have ques-tioned whether the eyes-closed an dth e visuab'vestibular-conflict condi-tions produce different performance.Billek-Sawhney5 foun d n o differenceson m easures of duration and swayamplitude in the eyes-closed andvisual-conflict condition s in neurolo gi-cally asym ptom atic (AS) y oung adults.No studies in the literature addressthese issues in older adults and indi-viduals with vestibular disorde rs.It is unclear whether patients improveo n re peated trials on the CTSIB, be-cause different investigator+ haveused d ifferent methods for calculatingperformance times and am ount ofsway. Physical therapists have a dvo-cated the use of balance retrainingthat involves repeated exposure todifferent sensory conditions whenstanding,7 but n o studie s have distin-guished between motor performanceon this test and motor learning as aresult of practice. Determ ining theneed for repeated trials during assess-ment would be useful.

'Alimed Inc, 68 HarrisonAve, Boston,MA 02111.

These findings suggest that the CTSIBshould b e studied further. Previousfindings suggest that therapists usingthe CTSIB should expect performanceon this test to vary with respect to ageand health status.6.S10This study hadseveral goals: (1) to de term inewhether healthy adults of differentages had different timed balancescores o n the CTSIB, (2) to deter min ewhether healthy subjects performeddifferently on each of the six condi-tions, (3) to learn whether individualsdiagnosed with vestibular disordersperform ed differently than AS sub -jects, and (4) to determine whethersubjects' performance im proved o vertrials.MethodSubjectsPilot data were collected from 22 sen-ior physical therapy students (9 m en ,13 wome n), aged 20 to 24 years@= 21.3 , SD=0.85). Subjects in theexperiment were divided into fourgroups. Groups 1,2, and 3 each com-prised 15 AS subjects. G ro up 1 com-prised 5 men a nd 10 wom en, aged 25to 44 years @ =39.3, SD=5.5). Gr oup2 comprised 4 me n and 11women,aged 45 to 64 years @=52.1, SD=6.2).Group 3 comprised 1man and 14wom en, aged 65 to 84 years @=75 .1,SD=5.9). No subjects we re ob ese.Subjects were screened for majorhealth problems, and only individualswith n o history of "dizziness," balancedisorders, or recent o rthopedic prob-lems we re included. Subjects ingroups 1 and 2 w ere recruited fromamo ng th e physical therapy students,SUE, an d faculty at the Medical Collegeof Ohio, Toledo, Ohio. Group 3 sub-jects were retired elderly people livingin the community.Gro up 4 comprised 17 patients (7me n, 10 wom en), aged 30 to 87 years@ =59 .8, SD= 18.9), diagnosed w ithvestibular disorders by a board-certified otolaryngologist specializingin vestibular disorders. In addition to

the clinical evaluation, diagnostic testsincluded computerized harmonicacceleration tests of the vestibulo-ocular reflex, optokinetic nystagmus,ocular pursuit and saccades, and ca-loric tests, duri ng which eye m ove-ments were recorded with electroocu-lography. Patients' diagnoses inc ludedbenign paroxysmal positional vertigo,vestibular n euronitis, cupu lolithiasis,labyrinthitis, and vestibular disorde rof idiopathic origin. Their initial com-plaints included vertigo, disequili-brium , and blurred vision. The physi-cian referred all patients for physicaltherapy at th e M edical College Hospi-tal. All subjects gave informed consentbefo re participating in this study.EquipmentThe materials for this test included a40.64x 40.64x 7.62-cm piece ofmedium-density Sunm ate* foam,2 avisuaUvestibular-conflict d o m e m a defrom a Chinese lantern attached to aplastic su n visor, and a stopwatch. (Asun visor is a hatless brim attached toan elastic band covered in terry cloth,which holds th e brim over the fore-head to shade the eyes.) We used asun visor that could be detached fromits elastic band, s o that ditferent bandscould b e used w ith each subject.Between test sessions, the elasticbands we re w ashed. This detail elimi-nated any concerns subjects mighthave had about hygiene. The domewas constructed according to thedescription by Shumway-Cook andHorak2 so that the subject saw a fixa-tion point, a larg e black cross, cen-tered in visual field. The total cost formaterials was approximately $40.Because the materials needed for thistest are inexpen sive, even clinics withsmall budgets can afford to obtain thenecessary equipm ent.ProcedureAll subjects we re tested for th ree trialon each of the six conditions, instocking feet. The conditions were(1) quiet standing on the floo r, look-ing straight ahead; (2) quiet standingon the floor with eyes closed; (3)quiet standing on the floor wearingthe conflict dome; (4) quiet standmg

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on the foam, with eyes open ; ( 5 )quiet standing on the foam, with eyesclosed; and ( 6 ) quiet standing o n thefoam wearing the conflict dome. Be-tween trials for conditions 4 through6 , the foam was turned over androtated 90 degrees to prevent thefoam from wearing unevenly overmany trials. Subjects rested betw eentrials, fo r 30 to 60 seconds, to elimi-nate the confounding effect of fatigue.Pilot work showed no effect of orderof conditions, with subjects who u n-derstooci the n ature of the task, whe nconditions 1 through 3 were givenbefore o r after conditions 4 through6 . Similarly, no dae renc es werefound when the orde rs of conditions2 an d 3 and conditions 5 and 6 werereversed. Performance is known to beaEected by the performer's level ofunderstanding of the skd l.ll Althoughthe postural control aspect of the testis presumably automatic, assumingthe correct position of the feet andhands could require som e practice tounderstand the nature of the task.Therefore, the experimental paradigmwas always administered using co ndi-tions 1 through 3 first t o give th esubjects the idea of the po sition re-quired. For that reason, condition 1,the least complicated con dition, al-ways preceded all other conditions,and condition 4 always precede d

b conditions 5 and 6 .- Prior to testing in each condition, theinvestigator demonstrated the task.The test was administered with theconditions in the same ord er eachtime. For all conditions, the subjectwas instructed to stand quietly, witharms co mfortably across the waist,feet togethe r, for as long as possible,up to 30 seconds. This period of timehad been specified in the originaldescription of the test.2 Th e instruc-tions given by all investigators we restandardized and were chang edslightly for each condtion.Prior to starting the test, subjects weretold that each trial would last for upto 30 seconds. For condition 1 , th einvestigator told the subject, "Standwith your feet together, hands acrossyou r waist, and look straight ahead.

Do this until I tell you to stop." Theinstructional set for the other condi-tions included the instruction to"close your eyes" for condition 2 an d"Now I'd like you to wear this hat andlook at the cross" for condition 3. Fo rconditions 4 through 6 , subjects w eregiven the same instruction regardingvisual conditions and were also askedto stand on the cente r of the foam.The length of time the subject couldmaintain balance was rec ord ed. A trialwas terminated when the subject'sarms o r feet changed position. Forsubjects wh o were able to perform all18 trials for 30 seconds, the test tookapproximately 20 minutes. All subjectswere tested in a quiet, well-lightedroom with a linoleum floor.Data AnalysisThe data were analyzed using themean time performing the test, overthe thre e trials for each condition.Test-retest reliability a nd interraterreliability were determ ined usingPearson Product-Moment CorrelationCoefficients. Differences am ong expe r-imental groups were determinedusing an analysis of variance (ANOVA)for repeated measures. Significantdifferences were then subjected topost hoc Tukey's tests. Differencesbetween AS subjects and age-matchedvestibularly impaired subjects wereexamined with t tests using the Bon-ferroni correction.ResultsBoth test-retest and interrater reliabil-ity were high (r=.99, Pc.01).Thesemeasures we re taken with the pilotgro up . Interrater reliability was evalu-ated by having two investigators at atime test five subjects simultaneously,using identical digital stopwatches.Values were round ed to th e nearesthalf secon d. T est-retest reliability wastested by having the same investigatortest five subjects twice.Th e ANOVA sho we d n o significantdifferences among grou ps fo r condi-tions 1 through 3 . That is, all subjectscould stand on the floor for 30 sec-onds with eyes ope n, eyes closed, and

wearing the conflict do me , for althree trials.The results were somewhat diffefor conditions 4 , 5 , and 6 (eyes oeyes closed, and wearing the condo me , respectively, while standinthe foam). As shown in Figure 1,co nfirm ed w ith the ANOVA, subjein groups 1 , 2 , an d 3 performed dition 4 for significantly longer thcondition 5 (F[16,34] 11.35, P


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40 Condition

n 30J8-n 2085mm

10

0 1 2 3 4

GroupFigure 1. Mean duration of balance in each group, by condition. Error bars repre-sent standard deviations. Condition 4=standing onfoam with eyes open, condition5=standing on foam with eyes closed, condition 6=standing on foam wearing visual/vestibular-conflictdome. Group I =asymptomatic subjects aged 25 to 44 years, group2=asymptomatic subjects aged 45 to M years, group 3=asymptomatic subjects aged 65to 84 years, group 4=uestibukarly impaired subjects.

Group40 1

8 2

30 3n42C . 4040 20853 10

0 4 5 6

Condition

Figure2. Mean duration of balance in each condition, by group. Error bars repre-sent standard deviations. See Fig. I legend for desn'ptons of groups and conditions.

g r ou p s 1 , 2 , and 3 performed signifi-cantly better than grou p 4 on condi-tions 5 and 6 (condition 5: t[l6]=4.17 ,P


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VesUbuladyImpaired Subjects

1 Condition 1Flgure 3. Dz$wences in balance duration between vestibularly impaired subjectsand age-matched asymptomatic subjects. Ewor bars represent standard deviations. SeeFig. 1 legend for descriptions of conditions.

-able 1. Mean Balance Scores (in Seconds)" for Each Group by TrialCondttlon 4' Condltlon 5" Condttlon6.Groupb Trlal 1 Trlal 2 Trlal 3 Trlal 1 Trlal 2 Trlal 3 Trlal 1 Trlal 2 Trlal 3*Standard deviations shown in parenthesesb ~ r o u p=asymptomatic subjects (n=15) aged 25 to 44 years, group 2=asymptomatic subjects(n=15) aged 45 to 64 years, group 3=asymptomatic subjects (n=15) aged 65 to 84 years, group4=vestibularly impaired subjects (n=17).'Condition 4=standing on foam with eyes opend~ on dit ion =standing on foam with eyes closed.

ular diso rders canno t. Therefore,condition may serve as a useful bline, particularly when assessing patients with vestibular disordersothe r balance problems.On condit ion 5, both the older gand the vestibularly impaired g roperformed more poorly than didyounger AS groups . These findinare consistent with th ose of previwork.10 The vestibularly impairedgro up performed at the sam e levthe older AS group, regardless ofOn the measure reported in thisstudy, youn ger subjects with vestlar impairments perfor med as if twere o lder people.O n condition 6, although the eldAS subjects had lower score s thantheir younger counterparts, they better able to perform this condithan sub jects with vestibular disoders. These data suggest that a scof 20 seconds o n condit ions 4, 5,6 with the feet together is withinnorm al limits for o lder subjects. Cdition 6 may also be useful in discriminating between older peoplwith and without vestibular disorWhen a therapist suspects a vestibdisorder in a patient without suchdiagnosis, these data may h elp thphysical therapist make a referralthe approp riate physician for evation. Such a difference may also buseful in reassessing patients aftecourse of physical therapy.Older AS and vestibularly impairesubjects tended to show higher swith successive trials o n the two ditions in which vision was elimino r not useful. This finding suggesthat these subjects may have usedunsuccessful movement strategy itially, but were able to mod* themotor plans with practice. This fiing may indicate that these subjectook longer than younger AS subto understand the motor require-ments of the task. Because the sujects with vestibular lesions had mvariability than o the r subjects, andbecause those subjects did improove r trials, it might b e useful to aminister this test using three or m

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trials and take the mean of thosetrials.This study examined subjects' abilityto maintain quiet upright standingwhe n sensory inputs were systemati-cally altered. Measures of sway c ouldprovide further insight into perfor-mance abilities of individuals in differ-ent age gro ups, but that issue was notexamined in this study because ob-semin g sway in the clinic would haverequired two observers or m ore so-phisticated, expensive equipment.On e purpo se of this study was tomake it easy for a single physicaltherapist to adm inister this test.

Although the CTSIB does not spec@the exact nature of a subject's balanceproblem , it is u seful in difFerentiatingbetween individuals with and w ithoutvestibular disorders. Th e test is alsouseful for obtaining data abou t pa-tients' performance before and aftertherapy, and thus in documenting theefficacy of treatm ent, for the benefit of

Commentary

third-par ty payers . Because the CTSIBis inexpensive, it is a useful option forclinics in which expensive dynam icposturography testing equipm ent isunavailable, but w here the therapistsstill need objective data ab out balance.AcknowledgmentsWe thank Rebecca Koch, FT, and Milli-cent Branch, FT, or their assistance.

References1 Horak FB. Clinical measurement of pos-tural control in adults. Phys Ther 1987;67:1881-1885.2 Shumway-Cook A, Horak FB. Assessing theinfluence of sensory interaction on balance:suggestion from the field. Phys Ther 1986;66:1548-1550.3 Nashner LM,McCollum G. The organizationof human postural movements: a formal basisand experimental synthesis. Behav Brain Sci.1985;8:135-172.4 Crowe TK, Deitz JC, Richardson PK, AtwaterSW. Interrater reliability of the pediatric clini-cal test of sensory interaction for balance.Physical and Occupational Therapy in Pediat-rics. 199O;lO:l-27.5 Billek-Sawhney B. Clinical and ObjectiveAssessment of Postural Stabilify. Pittsburgh, Pa:University of Pittsburgh; 1990. Thesis.

6 Di Fabio RP, Badke MB. Relationship of sen-sory organization to balance function in pa-tients with hemiplegia. Phys Ther. 1990;70:542-548.7 Toal Tangeman P, Wheeler J. Inner ear con-cussion syndrome: vestibular implications andphysical therapy treatment. ~ o p i i sn AcuteCare Trauma Rehabilitation. 1986;1:72-83.8 Pyykko I, Aalto H, Hytonen M, et al. Effect ofage on posture control. In: Amblard B,Benhoz A, Clarack E, eds. Posture and Gait:Development, Adaptation, a nd M odulation.Amsterdam, the Netherlands: Elsevier; 1988:95-104.9 Straube A, Botzel K, Hawken M , et al. Pos-tural control in the elderly: differential effectsof visual, vestibular and somatosensory input.In: Amblard B. Benhoz A Clarack E, eds. Pos-ture an d Gait:'~ e v e l o ~ m t k z t ,daptation, an dModulation. Amsterdam, the Netherlands: El-sevier; 1988:105-114.10 Woollacott MH. Aging, posture control andmovement preparation. In: Woollacott MH,Shumway-CookA, eds. Posture an d GaitAcross the LiJespan. Columbia, SC: University ofSouth Carolina Press; 1989:155-175.11 Gentile AM. A working model of skill ac-quisition with application to teaching. Quest,1972;17:%23.12 Norre ME, Forrez G, Beckers A. Vestibularhabituation training and posturography on be-nign paroxysmal positioning vertigo. ORLJOtorhino laryngo l Relat Spec. 1987,4922-25.

The developm ent of effective metho dsfor assessing and treating adults withvestibular deficits is a p romin ent issuefor physical therapists and occupa-tional therapists involved with "vestibu-lar rehabilitation." The article by Co-hen et al provides a vehicle for thekind of dialogue that is need ed aboutthis important topic. I would conside rtheir study preliminary, however, inview of several issues related to thebroad generalization of their results,the inconsistency of age-m atched com-parisons, the recommendation to de-lete various aspects of t he Clinical Testof Sensory Interaction o n Balance(CTSIB), and the absen ce of a do cu-mented relationship between stanceduration an d functional status in pa-tients with vestibular impairments.

Generallzatlon of FlndlngsThe primary conclusion reported byCohen a nd colleagues was that theCTSIB ". . . is useful in differentiatingbetween individuals with and withoutvestibular disorders." I believe thatthis conclusion is potentially mislead-ing for several reasons:1. Su bjects with a nd witho ut activevertigo have equivalent scores ontests of sen sory interaction ac-quir ed with posturography.' Theconditions used for evaluatingbalance with posturography andthe CTSIB are essentially the sam e.Posturography, however, incorpo-rates a forc e platform an d a visualenclosure that can be referenced

to spontaneous displacements ofthe subject's center of force.2 Pos-turography provides a mo re sensi-tive measu re of balance comparedwith th e CTSIB becau se manipula-tion of the sensory environmen t isprecisely controlled and equilib-rium scores are derived from verti-cal floor reaction forces. It is un-likely, therefore, that the CTSIBwill identify sensory integrationdeficits in m any patients with ver-tigo, because m ore sensitive mea-sures d o not detect deficits relatedto this symptom.Subjects with compensated (chron-ic) unilateral peripheral vestibularimpairments often have normalbalance responses when tested

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A Study of the Clinical Test of Sensory Interaction and Balance