doi: 10.2522/ptj.20100432Originally published online October 27, 2011

2012; 92:279-288.PHYS THER. Johan Kvalvik StanghelleArve Opheim, Reidun Jahnsen, Elisabeth Olsson andAdults With Spastic Bilateral Cerebral PalsyBalance in Relation to Walking Deterioration in

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Balance in Relation to WalkingDeterioration in Adults With SpasticBilateral Cerebral PalsyArve Opheim, Reidun Jahnsen, Elisabeth Olsson, Johan Kvalvik Stanghelle

Background. Balance function is central in walking, and impaired balance func-tion may be related to walking deterioration in adults with spastic bilateral cerebralpalsy (CP).

Objectives. The purposes of this study were: (1) to compare balance confidence,fear of falling, and balance ability in adults with spastic bilateral CP, with and withoutself-reported walking deterioration; (2) to characterize balance confidence, fear offalling, and balance ability across all participants; and (3) to examine the relationshipbetween balance confidence and balance ability across all participants.

Design. A case-control design was used.

Methods. Sixteen adults from a 7-year follow-up study who had spastic bilateralCP and were under 40 years of age in the 2006 survey participated. Eight participantsreported walking deterioration (cases), and 8 participants did not report walkingdeterioration (controls). Outcome variables were: the Activities-specific BalanceConfidence (ABC) Scale, the Falls Efficacy Scale–International (FES-I), and the BalanceEvaluation Systems Test (BESTest).

Results. No differences in any of the outcome variables were found between thecases and the controls. Across all participants, the ABC Scale and FES-I scores were62% and 24 points, respectively. Reduced ABC Scale scores and increased FES-I scoreswere found when using escalators, walking in crowds, and walking on slipperysurfaces. The BESTest subscale scores were 60% to 79% of the maximum score, butonly 31% and 42% of the maximum score in postural responses and anticipatoryadjustments, respectively. Balance confidence correlated positively with posturalresponses, sensory orientation, stability in gait, and BESTest total score.

Limitations. The lack of reliability and validity tests for the outcome variables inthis study population and the small number of participants were limitations of thestudy.

Conclusions. Self-reported walking deterioration in this group could not beexplained by differences in balance confidence, fear of falling, or balance ability.Across all participants, most balance problems seemed related to reduced posturalresponses and anticipatory adjustments.

A. Opheim, PT, MSc, KarolinskaInstitutet, Stockholm, Sweden,and Sunnaas Rehabilitation Hos-pital, 1450 Nesoddtangen, Nor-way. Address all correspondenceto Mr Opheim at: arvei.opheim@sunnaas.no.

R. Jahnsen, PT, PhD, SunnaasRehabilitation Hospital, andDepartment of Clinical Neuro-sciences in Children, Oslo Univer-sity Hospital, Rikshospitalet, Oslo,Norway.

E. Olsson, PT, PhD, KarolinskaInstitutet.

J.K. Stanghelle, PhD, MD, SunnaasRehabilitation Hospital, and Fac-ulty of Medicine, University ofOslo, Oslo, Norway.

[Opheim A, Jahnsen R, Olsson E,Stanghelle JK. Balance in relationto walking deterioration in adultswith spastic bilateral cerebral palsy.Phys Ther. 2012;92:279–288.]

© 2012 American Physical TherapyAssociation

Published Ahead of Print:October 27, 2011

Accepted: September 5, 2011Submitted: December 22, 2010

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High levels of fatigue, pain, anddeterioration of walking havebeen reported in adults with

cerebral palsy (CP).1–7 In our 7-yearfollow-up study of people with spas-tic unilateral and bilateral CP in2006,7 a substantial increase in theproportion of people reporting walk-ing deterioration was seen in theages of 35 to 40 years in people withspastic bilateral CP. Those reportingwalking deterioration also reportedsignificantly higher levels of bothmusculoskeletal pain and physicalfatigue. Seventy-eight of the 149 peo-ple with spastic CP reported deteri-oration in walking in adult age, and51 of the 78 reported that this dete-rioration was characterized byreduced balance.7 These findings ledus to focus on balance as an impor-tant factor for early walking deterio-ration in people with spastic CP.

Postural stability, also referred to asbalance, is the ability to control thecenter of mass in relationship to thebase of support.8 In order to main-tain balance during a certain task,complex processes take placeinvolving vestibular, somatosensory,visual, cognitive, and musculoskele-tal systems, controlling the relation-ships among the different body seg-ments and between the body and theenvironment.9,10 Balance has beendescribed as one of the prerequisitesfor walking11 and was found to beimpaired in children with CP.12,13

Burtner et al14 found that childrenwith spastic bilateral CP had aproximal-to-distal muscle activationpattern, more co-contraction, andslower muscle activation comparedwith children with typical develop-ment. To the best of our knowledge,studies of balance in adults with CPhave not been carried out.

In order to gather more informationabout balance in adults with spasticbilateral CP, we invited 3 adults toshare their experiences in a groupdiscussion. They revealed that walk-

ing on uneven or slippery ground,walking in crowds, using escalatorsand public transportation, and walk-ing down stairs were difficult situa-tions that challenged their balancereactions. They often felt too slowand unable to prevent a fall.Impaired vision and reduced lightingconditions presented additionalproblems. These difficulties oftenled to compensatory strategies suchas holding on to railings or otherobjects. Some participants in thegroup discussion regarded them-selves as “expert fallers” (ie, theyoften fell but had not had seriousinjuries and were not afraid of fall-ing). Others reported that they wereafraid of falling.

These described difficulties may leadto an increased risk of falling, inju-ries, and a gradual reduction in walk-ing frequency and distance, thuscontributing to walking deteriora-tion. This deterioration might reduceactivity participation in the commu-nity at a far earlier age than would beexpected due to normal aging. How-ever, studies of balance ability and itsrelationship to walking deteriorationin adults with spastic bilateral CP arelacking.

Our previous 7-year follow-up study7

indicated an association betweenimpaired balance and walking dete-rioration, as 51 of 78 peopleregarded the deterioration as a resultof reduced balance. Of those withunchanged or improved walking(n�71), 26 regarded their walkingability to be a result of improvedbalance.7 Walking deterioration wasmore common in individuals withspastic bilateral CP.7 Given theseresults, the lack of research in thearea, and the information from thegroup discussion, the first purposeof this study was to compare balanceconfidence, fear of falling, and bal-ance ability in adults with spasticbilateral CP, with and without self-reported walking deterioration. The

second purpose was to describe bal-ance confidence, fear of falling, andbalance ability across all participants.The third purpose was to examinethe relationship between balanceconfidence and balance ability acrossall participants.

MethodDesignA case-control design was chosen tocompare people who reported walk-ing deterioration (cases) with peoplewho did not (controls).

SettingThe testing took place during thefall of 2009 in the Motion AnalysisLaboratory at Sunnaas RehabilitationHospital, Norway, and was con-ducted by trained and experiencedmultidisciplinary personnel.

ParticipantsThe participants were recruitedfrom a 7-year follow-up study of 149adults with spastic unilateral andbilateral CP in 2006.7 In a mailedletter, we invited all people withspastic bilateral CP who reportedGross Motor Function ClassificationSystem (GMFCS) levels I throughIII15 and were under 40 years of agein the 2006 survey to participate.Individuals who were unable to walkat least 10 m without walking aidswere excluded. A flow chart of theinclusion process is presented in Fig-ure 1. Sixteen adults (5 men, 11women) with documented spasticbilateral CP, GMFCS levels II (n�15)and III (n�1), agreed to participate(Tab. 1).

ProcedureThe Activities-specific Balance Confi-dence (ABC) Scale was administeredin a telephone interview by a physi-cal therapist 2 to 3 weeks before thesemistructured interview and thetests of balance ability in the labora-tory. This physical therapist did nottake part in the other assessments. Inthe semistructured interview, carried

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out by the principal investigator(A.O.), the changes in walkingfunction over the years (since theend of adolescence) were reas-sessed and categorized as improved,unchanged, or deteriorated. Eachparticipant’s Falls Efficacy Scale–International (FES-I) and FunctionalMobility Scale (FMS) scores, GMFCSlevel, and history of falls also wereobtained during this interview. Allassessments were carried out in thesame order: first the semistructuredinterview, then tests of muscle toneand muscle strength, followed by thetests of balance ability. The principalinvestigator led and administered allbalance tests, assisted by at least oneother person (physical therapist orbiomechanist) who observed andregistered the performance of thetests of balance ability and aided inparticipants’ safety. The principalinvestigator was blinded to the ABCScale scores until after the tests ofbalance ability. When there weredoubts about the scorings on thetests of balance ability, these doubtswere discussed, and the principalinvestigator had the final word.

Descriptive VariablesThe GMFCS15 was used to assessgross motor function. The GMFCScategorizes gross motor functioninto 5 levels, with level I being thehighest and level V being the lowestfunctional level. The need for rail-ings when descending stairs wasused to distinguish between levels Iand II. The GMFCS has been found tobe valid and reliable in adults withCP.16,17

The FMS18 was used to describe thelevel of independent walking on ascale of 1 to 6 points (1�wheelchairuser, 6�fully independent on all sur-faces) over 5, 50, and 500 m, respec-tively. The FMS has been found to beboth reliable and valid in childrenwith CP.18

Muscle tone in the triceps surae, rec-tus femoris, hamstring, and adductormuscle groups was assessed bilater-ally using the 6-level modified Ash-worth scale (MAS) (0–5),19 whichassesses resistance to rapid, passivemovements. Higher scores indicatehigher muscle tone. The medianMAS score for these muscle groupswas calculated. Bohannon andSmith19 found an agreement of 87%between 2 raters who used the MASto assess muscle tone in the elbowflexors, but the reliability of the MASwas found to variable in later stud-ies.20 The validity of the MAS in theassessment of muscle spasticity hasbeen questioned,20,21 but it is still themost common clinical scale forassessing muscle tone by grading theresistance to passive movements,22

acknowledging that this assessmentalso includes mechanical compli-ance in muscle and joints.23

Muscle strength in the hip flexors,extensors and abductors, knee flex-ors and extensors, and ankle plantarflexors and dorsiflexors, bilaterally,was assessed using the 0–5 grademanual muscle test scale.24 Higherscores indicate stronger muscles.The median muscle strength scorefor these muscles was calculated.Manual muscle test scores have beenfound to correlate (r�.768, P�.001)with the results of dynamometertesting.25

Outcome VariablesBalance confidence and fear of fall-ing were assessed with the ABC

Figure 1.Flow chart of the inclusion of participants for the present study. CP�cerebral palsy,GMFCS�Gross Motor Function Classification Scale.

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Scale and the Norwegian version ofthe FES-I, respectively. Balance abil-ity was tested with the Balance Eval-uation Systems Test (BESTest) andthe Four-Square Step Test (FSST).These scales and balance ability testswere chosen because they cover sev-eral of the balance problems men-tioned in the group discussion, suchas fear of falling, maintaining balancewhile performing different activities,balance reactions, and stepping overobstacles.

The ABC Scale (with scoresexpressed as a percentage) was usedto quantify, from 0 to 100 (0�not atall), the confidence a person had innot losing balance while performing16 activities in daily living.26 Thescale has been used extensively inboth balance and fall preventionresearch in the elderly population

and has good psychometric proper-ties.27 It was found to be valid andreliable in people who were healthyand frail elderly people, in peoplewith a history of falls, and in patientswith Parkinson disease.26,28,29

The Norwegian version of the FES-Iwas used to grade fear of falling dur-ing different activities in daily livingon a 4-point scale (1�not at all con-cerned, 4�very concerned), giving atotal scoring range of 16 to 64points.30–32 It is widely used interna-tionally in the field of fall preventionand has been found to be reliableand valid for community-dwellingelderly people and elderly patientswho were treated for fall-relatedfractures.33,34

The BESTest was used to assess dif-ferent subsystems related to bal-

ance.35 It contains 6 subscales cover-ing these different subsystems: I—biomechanical constraints, II—sta-bility limits/verticality, III—antici-patory postural adjustments, IV—postural responses, V—sensory ori-entation, and VI—stability in gait.The BESTest consists of 27 items,some of which are divided into 2 to4 sub-items (eg, for left and rightsides), resulting in a total of 36 tasks.All items are scored on a 4-categoryordinal scale from 0 (not able orabsent) to 3 (normal), and the scoresare summed for each subscale. Thesum of the 6 subscale scores is theBESTest total score. The BESTest sub-scale and total scores are reported asa percentage of the maximum score.

The FSST (in seconds) was used totest the participant’s ability to stepover a low obstacle in all 4 directions

Table 1.Characteristics of the Participants in the Study (N�16)a

Variable All Cases (n�8) Controls (n�8)

Female/male, n 11/5 5/3 6/2

Age (y), median (Q1–Q3) 38 (31–40) 39 (31–42) 36 (31–39)

Body mass index (kg/m2), median(Q1–Q3)

24.7 (23.1–31.4) 25.0 (23.5–37) 24.7 (22.7–27.1)

GMFCS level II/III, n 15/1 8/0 7/1

MAS,b median (Q1–Q3) 2.0 (1.6–2.5) 2.0 (2.0–2.4) 2.0 (1.1–2.9)

Muscle strength,c median (Q1–Q3) 4.0 (3.6–4.0) 4.0 (3.1–4.0) 4.0 (4.0–4.0)

Falls in the previous month, n

0 7 3 4

1–2 4 2 2

3–8 4 2 2

20 1 1 0

Falls in the previous year, n

�5 3 1 2

5–10 6 3 3

11–25 3 1 2

26–50 1 1 0

�51 3 2 1

a Q1–Q3�first through third quartiles, GMFCS�Gross Motor Function Classification Scale.b Modified Ashworth scale (MAS) (0–5), median score of triceps surae, rectus femoris, hamstring, and hip adductor muscles. Higher scores indicate highermuscle tone and greater resistance to rapid, passive movements. The original MAS scores were coded as: 0�0, 1�1, 1��2, 2�3, 3�4, and 4�5.c Manual muscle test (0–5), median score of hip flexors, extensors, and abductors, knee flexors and extensors, and ankle plantar flexors and dorsiflexors.Higher scores indicate stronger muscles.

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in a given sequence as fast as possi-ble.36 The FSST was found to havegood test-retest reliability, it corre-lated well with other gait mea-sures,37 and it was feasible and validfor testing dynamic balance inpatients who were ambulatory afterstroke.38

BiasBias was controlled for by having theprincipal investigator (A.O.) adminis-ter the FES-I and FMS, assess GMFCSlevel, and lead all tests of balanceability. At least 2 people were alwayspresent during all balance tests. Theprincipal investigator was blinded tothe scores on the ABC Scale duringthe tests of balance ability. He wasnot blinded to whether the partici-pants had reported deterioratedwalking. All participants gave writ-ten informed consent.

Data AnalysisWe used SPSS version 15.0 statisticalsoftware (SPSS Inc, Chicago, Illinois)to analyze the data. Because of thesmall number of participants and theexplorative nature of the study, non-parametric statistics were usedthroughout the study. Descriptivevariables are presented with frequen-cies for history of falls and GMFCSlevels and with medians and inter-quartile ranges (Q1–Q3) for musclestrength and MAS. All outcome vari-ables (ABC Scale, FES-I, BESTest, andFSST) are presented with mediansand interquartile ranges (Q1–Q3).39

For the case-control study, thebetween-group differences in ABCScale, FES-I, BESTest (subscale andtotal), and FSST scores were testedwith the Mann-Whitney U test.39 Therelationship between balance confi-dence and the BESTest subscalescores, BESTest total scores, andFSST scores was tested with scatterplots and Spearman rho (rs) correla-tion coefficient. The 95% confidenceinterval (CI) for the correlation coef-ficient was calculated with Vas-sarStats.40 The correlation coeffi-

cient was interpreted according toDomholt41: 1.00–0.90�very high;0.89–0.70�high; 0.69–0.50�mod-erate; 0.49–0.26�low; and 0.25–0.00�little, if any correlation.

ResultsThe descriptive variables of the par-ticipants are presented in Table 1.Eight participants reported deterio-rated walking over the years (cases),and 8 participants reported eitherimproved (n�2) or unchanged (n�6) walking (controls) (Tab. 1). TheFMS showed that 15 participantswere independent walkers on evensurfaces over 50 m, and 12 partici-pants were independent walkersover 500 m (data not shown). Therewere frequent falls among the par-ticipants, but no serious injurieswere reported. There were no signif-icant differences between the casesand the controls for the descriptivevariables (Tab. 1). There were nodifferences in ABC Scale and FES-Iscores between the participants whoreported deteriorated walking andthose who did not, nor were thereany differences in BESTest subscalescores, BESTest total scores, or FSSTscores (Tab. 2).

For the whole group, the scores onthe ABC Scale showed the lowestconfidence in balance during theactivities “stepping on or off an esca-lator without holding the railings,”“walking on an icy surface,” and“stand on chair and reach” (Fig. 2).The overall ABC Scale score acrossall activities was 62% (Q1–Q3�37–70) confidence in not losing balance.

The FES-I showed the greatest fear offalling during the activities “walk ona slippery surface” and “walk up ordown a slope,” with median scoresof 3 (Q1–Q3�2–4) and 2 (Q1–Q3�2–4), respectively. The medianFES-I summed score was 24 points(Q1–Q3�21–34). For 12 of the 16items, the participants reported noor little fear of falling (Tab. 2).

The BESTest showed the lowestscores (percentage of the maximumscore) for anticipatory posturaladjustments (subscale III), with amedian score of 42 (Q1–Q3�39–54), and for postural responses (sub-scale IV), with as median score of31 (Q1–Q3�18–58). The medianscores for the other subscales rangedfrom 60% to 79% of the maximumscore (Tab. 2). The BESTest totalscore (percentage of the maximumscore) showed a median score of 60(Q1–Q3�55–68) (Tab. 2). The FSSTshowed a skewed distribution, with2 distinct outliers. The median timeto complete the stepping sequencewas 16 seconds (Q1–Q3�11–22)(Tab. 2).

The relationship between balanceconfidence and balance abilityshowed a moderate positive correla-tion between the ABC Scale scoresand the BESTest subscale IV, V, andVI scores and BESTest total scores(Tab. 3). The tests of balance abilitywere easily understood by the partic-ipants, there were no major practicalproblems during the testing, and allparticipants completed all tests.

DiscussionThere were no differences in balanceconfidence, fear of falling, and bal-ance ability in adults with spasticbilateral CP, with and without self-reported walking deterioration. Thisfinding might reflect a more com-plex interaction between walkingdeterioration and balance than orig-inally hypothesized. The variabilityin the outcome variables in bothgroups was substantial. Differentsocial roles and exposure to differentcontextual factors at work, in thefamily, and during leisure time, aswell as personal factors, put dif-ferent demands on both balance andwalking. A small change in balanceability, therefore, might have a con-siderable impact on walking forsome people with high functionaldemands and expectations, whereas

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for people with smaller demandsthese changes might go unnoticed.The groups had similar median levelsand range of both muscle strengthand muscle tone, and as 12 of the 16participants were independent walk-ers over more than 500 m, the sam-ple size was too small to detect apossible between-group difference.

If there are changes in balance abilityover time in adults with spastic bilat-eral CP, they might be the result ofslow processes involving both neuraland musculoskeletal structures, suchas slower proprioception, signal pro-cessing and execution, contractures,and reduced muscle strength. Theseprocesses might take a long time todevelop before they result inreduced balance and later affectwalking. Therefore, a prospective,longitudinal study of both walkingand balance ability would have beenthe preferred design. However, aslittle is known about the optimalfollow-up time, the most relevantoutcome variables, or the balance in

this group, we decided to use across-sectional study design in thisstudy.

The BESTest showed reductions inall subsystems of balance, withanticipatory adjustments and pos-tural responses being the mostaffected. Difficulties with anticipa-tory postural adjustments pointstoward reduced ability to antici-pate the effect of movements onbalance. When anticipating a poste-riorly directed push, the anteriormuscles must be activated and thebody center of mass directed for-ward. These mechanisms are resultof experience and motor learn-ing,8,42 but are known to be slow anddelayed in children with CP.8

The difficulties related to posturalresponses are in accordance withGage et al,11 who described the equi-librium problem as one of the pri-mary abnormalities of gait in chil-dren with CP. Reduced posturalresponses in children with CP com-

pared with children developing typ-ically also were found by Burtneret al.12 The ability to take a rapid stepto regain balance is a crucial posturalresponse to avoid falls and is proba-bly a primary problem in adults withCP as well. Lajoie and Gallagher28

found significantly higher reactiontimes in “fallers” than in “nonfallers”in a group of elderly people.

In people with spastic CP, bothanticipatory adjustments and pos-tural responses can be affected bythe brain lesion itself. Increasedantagonistic coactivation,14 perhapsas a strategy to cope with reducedpostural control,42 a top-down mus-cle activation,43 a reduced ability tomodulate electromyography ampli-tude,44 and muscle weakness andjoint impairments also are likely tobe contributing factors. For overallbalance, the BESTest total score was60% of the maximum score, and theBESTest subscale scores ranged from31% to 79% of the maximum score.These scores were considerably

Table 2.Comparison of Balance Confidence, Fear of Falling, and Clinical Balance Tests Between People Who Reported DeterioratedWalking (n�8) and Those Who Did Not (n�8) in a Group of Adults With Spastic Bilateral Cerebral Palsy (N�16)a

MeasureDeteriorated

WalkingNondeteriorated

Walking P b All

ABC Scalec (%) 62 (32–76) 58 (46–70) .713 62 (37–70)

FES-Id (16–64) 24 (22–36) 26 (19–34) .804 24 (21–34)

BESTeste (%)

I 57 (49–73) 60 (55–67) .798 60 (53–72)

II 76 (76–85) 84 (71–86) .645 79 (72–86)

III 39 (35–50) 44 (39–60) .328 42 (39–54)

IV 28 (18–63) 36 (18–56) .878 31 (18–58)

V 64 (45–78) 67 (50–73) .959 67 (50–73)

VI 67 (60–71) 69 (67–76) .505 67 (67–75)

Total 58 (53–68) 60 (57–71) .505 60 (55–68)

FSSTf (s) 19 (15–28) 12 (10–20) .130 16 (11–22)

a All scores presented as median and interquartile range (Q1–Q3).b Nonparametric Mann-Whitney U test.c ABC Scale�Activities-specific Balance Confidence Scale (0%–100%). Higher score indicates higher confidence of not losing balance across 16 differentactivities.d FES-I�Falls Efficacy Scale–International. Higher score indicates greater fear of falling during 16 different activities.e BESTest�Balance Evaluation Systems Test (0%–100% of maximum score). Higher score indicate better balance. BESTest subscales: I�biomechanicalconstraints, II�stability limits/verticality, III�anticipatory postural adjustments, IV�postural responses, V�sensory orientation, VI�stability in gait.f FSST�Four-Square Step Test.

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lower than those in the study byLord et al,45 who found BESTestscores of 80% to 90% of the maxi-mum in elderly people who werehealthy.

The overall balance confidence was62%, which is the same level as inelderly people with a history of hipfracture46 and lower than incommunity-dwelling elderly peo-ple.47 Lajoie and Gallagher28 foundthat a cutoff ABC Scale score of 67%could predict fallers in the elderlypopulation with a sensitivity of 84%

and nonfallers with a specificity of88%. The high number of fallers inthe present study suggests an evenhigher cutoff point in this group.There were substantial differences inABC Scale scores for the differentactivities. The ABC Scale scores werelowest when using escalators andwalking on icy surfaces. In 7 of the16 activities, the median scoresshowed more than 80% confidenceand, consequently, did not reflectthe balance problems of the studygroup. Not surprisingly, fear of fall-ing showed a trend similar to that of

balance confidence. Delbaere et al33

found cutoff points for low (16–19),moderate (20–27) and high (28–64)concern in community-dwellingelderly people. Fear of falling in thepresent study was moderate, andslightly lower than in a group of peo-ple with spinal cord injury48 and in agroup of women with osteoporo-sis.49 It was at about the same level asin the validation study by Delbaere etal33 and as in elderly people whowere treated for fall-related frac-tures.34 There was a high prevalenceof fallers in the present group, but no

Figure 2.Box plot of the scores on the different items of the Activities-specific Balance Confidence (ABC) Scale of 16 adults with spastic bilateralcerebral palsy. A score of 100 represents 100% confidence in not losing balance during an activity, thus higher scores representhigher balance confidence. The boxes represent 50% of the observations (Q1–Q3), the black line shows the median score, and theerror bars show the minimum and maximum values. The outliers are those that lie between 1.5 and 3 box lengths from the loweror upper edge of the box.

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reports on fractures due to falls,which might partly correspond to“expert fallers” (ie, those who falloften, but without injuries and fearof falling). However, the risk of aninjurious fall, reduced balance confi-dence, and fear of falling, especiallyin outdoor and community activities,might substantially restrict bothsocial and community participationfor these relatively young people.Fatigue also is a factor that mighthave an impact on both balance andfalls, but this relationship was notassessed in this study.

The relationship between balanceconfidence and balance abilityshowed a moderate positive correla-tion for the BESTest subscales of pos-tural responses, sensory orientation,and stability in gait and for the BEST-est total score. The correlationbetween postural responses and bal-ance confidence suggests that areduced ability to react to externalperturbations with a rapid step has anegative impact on balance confi-dence. The proximal-to-distal activa-tion pattern found in children withCP43 indicates a reduced ability touse an ankle strategy for regainingbalance. Thus, a reduced ankle strat-

egy in addition to the reduced pos-tural responses, creates a doubleproblem, as both the most adequatebalance adjustment strategy and theability to take rapid steps to regainbalance are reduced. The reducedpostural responses may be con-firmed by the low score of balanceconfidence when using escalatorsand walking on slippery surfaces.Sensory orientation, as evaluated inthe test, can be the result not only ofimpaired sensory systems such asvision, the vestibular system, andproprioception, but also of animpaired motor output (ie, taskexecution). Both sensation and pro-prioception often are affected inCP.50 The group discussion high-lighted balance problems duringdim light conditions, when com-pensatory mechanisms (eg, visionfor reduced proprioception) areno longer available. Stability in gait,as tested in the BESTest, includeswalking under different conditionsthat challenge the balance. Impairedbalance during walking may reducethe balance confidence and, there-fore, could explain the correlationbetween stability in gait and balanceconfidence. A positive correlationbetween balance confidence and bal-

ance ability was found by Horak etal35 (r�.64) and by Sihvonen et al46

(r�.74), and confirmed by the pres-ent study.

The positive correlation betweenbalance confidence and the scoreson BESTest subscales IV, V, and VIand the BESTest total score suggeststhat the participants had a realisticperception of their own balance.The fact that there were no correla-tions between balance confidenceand scores on BESTest subscales I, II,and III may be due to the mixture ofdifferent body functions and struc-tures in these subscales, as well asthe small number of participants.The FSST had little, if any, correla-tion with balance confidence, asalso shown by Whitney et al37 in peo-ple with vestibular dysfunctions.The FSST includes tasks with differ-ent levels of difficulty, a variationthat may have different effects onbalance confidence and result inincreased FSST time. For instance,the reduced ability to step backwardmay have a different effect on thebalance confidence than a reducedability to take a step forward orsideways.

These results confirmed the balanceproblems described in the group dis-cussion and highlight the specific bal-ance problems in this group. Theseproblems were at the same level asin the elderly population treated forfall-related fractures, and thus theycan be in need of targeted interven-tions. No major practical problemswere encountered during the testing,indicating the practical feasibility ofthese tests in this population.

Future research should focus onlong-term changes in balance in aprospective, longitudinal designamong people who have spastic CPand on the relationship betweenchanges in balance ability and walk-ing. Furthermore, there is a need for

Table 3.Correlations Between Balance Confidence and Balance Ability in Adults With SpasticBilateral Cerebral Palsy (N�16)a

MeasureActivities-specific Balance

Confidence Scale

BESTestb

I .45, P�.084

II .24, P�.36

III .29, P�.27

IV .52 (95% CI�.04, .81), P�.04

V .52 (95% CI�.04, .81), P�.038

VI .57 (95% CI�.10, .83), P�.022

Total .57 (95% CI�.10, .83), P�.022

Four-Square Step Test �.346, P�.189

a Correlation coefficients with 95% confidence intervals (CI) were obtained using Spearman rho (rs);the CIs are given where significant correlations were found, P�.05.b BESTest�Balance Evaluation Systems Test. BESTest subscales: I�biomechanical constraints, II�stabilitylimits/verticality, III�anticipatory postural adjustments, IV�postural responses, V�sensory orientation,VI�stability in gait.

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studies on the reliability and validityof these balance tests in this group.

Study LimitationsThe reliability and validity of the out-come variables for use with thisgroup were not previously tested.The number of participants in thisstudy was relatively small; therefore,this study should be regarded asexploratory, and the results of thebetween-group comparisons shouldnot be generalized to a larger group.However, the study group was not aconvenience sample, but a specificsubgroup of people recruited fromour previous follow-up study.

ConclusionSelf-reported walking deteriorationin this group of adults with spasticbilateral CP could not be explainedby differences in balance confi-dence, fear of falling, or balance abil-ity in this exploratory study. Acrossthe whole group, most balance prob-lems seemed related to reduced pos-tural responses and anticipatoryadjustments. Fear of falling was atthe same level as in elderly peoplewith fall-related fractures. Thoseindividuals with higher balance con-fidence scored better on several ofthe tests of balance ability.

Mr Opheim, Dr Jahnsen, and Dr Olssonprovided concept/idea/research design. Allauthors provided writing. Mr Opheim pro-vided data collection. Mr Opheim and DrOlsson provided data analysis. Mr Opheimand Dr Stanghelle provided project manage-ment. Dr Stranghelle provided fund procure-ment and facilities/equipment. Dr Olssonand Dr Stanghelle provided institutionalliaisons. Dr Jahnsen, Dr Olsson, and DrStanghelle provided consultation (includingreview of manuscript before submission).The authors thank all of the participants andthe personnel at the Motion Analysis Labo-ratory, Sunnaas Rehabilitation Hospital, fortheir respective contributions to the study.

This article was published as part of MrOpheim’s PhD thesis at Karolinska Institutet,Stockholm, Sweden.

Ethical approval for the study was obtainedfrom the Regional Ethics Committee in

Southeastern Norway (Ref. ID: 1.2006.952and 2009/119) and the Commissioner forthe Protection of Privacy in Research.

This research, in part, was presented at the4th Journee Regionale du Reseau Breizh IMC;Rennes, France; February 1, 2011.

This study was financially supported bythe Research Council of the South-EasternRegional Health Authority in Norway.

DOI: 10.2522/ptj.20100432

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doi: 10.2522/ptj.20100432Originally published online October 27, 2011

2012; 92:279-288.PHYS THER. Johan Kvalvik StanghelleArve Opheim, Reidun Jahnsen, Elisabeth Olsson andAdults With Spastic Bilateral Cerebral PalsyBalance in Relation to Walking Deterioration in

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