Brain & NeuroRehabilitation ol. 6, No. 2, September, 2013 http://dx.doi.org/10.12786/bn.2013.6.2.58 뇌질환환자의균형및자세평가 국립재활병원재활의학과 김은주 Assessment of Balance and Posture in Brain Disorders Eun Joo Kim, M.D. Department of Physical Medicine and Rehabilitation, National Rehabilitation Hospital Balance, the ability to maintain the center of gravity over the base of support within a given sensory environment, is composed of several subcomponents and influenced by several systems (sensory, musculoskeletal, and central and peripheral nervous systems). The assessment and management of balance and posture in brain disorders are complex. To make a reasonable choice about balance scales to use, it is important to understand the balance system, to have a careful understanding about measurement tools in brain disorders and have a comprehensive way to assess balance function and dysfunction. This is a challenge for balance activity measurement tools as the most balance scales needs underlying theoretical approach behind the clinical assessment. Further research is needed to develop the theoretical construct with ecological validity, the hierarchy conceptual scale and combine the individual test to the patients level of balance ability. And assessment of the minimum detectable change in each test should be included and paid attention that is vital for clinical interpretation of scores. In conclusion, a thorough assessment into the cause of balance dysfunction in brain disorders is essential to the implementation of appropriate treatment, usually a multidisciplinary approach. (Brain & NeuroRehabilitation 2013; 6: 58-63) Key Words: assessment, brain injuries, postural balance, stroke 서론 및자세평가에대해포괄적으로논의하고자한다. 균형 (balance) 이란주어진환경내에서자신의기저면 (base of support) 위에신체중심을유지하는능력으로다양한인자들의영향을받는일련의복합과정이다. 1 즉, 하나의시스템이나정향 (righting), 평형 (equilibrium) 반사의결과물이라기보다많은감각-운동-인지반응들의상호작용에기인된복합운동기술이라할수있다. 2 다양한원인에의해발생된뇌질환환자들은신체균형기능의기본이되는감각계의인지, 중추신경계를통한감각운동정보통합, 이에대한근육반응과동시에환경에대한올바른운동대응전략 (movement strategies) 능력저하가동반되는경우가많으므로균형에대한문제를흔히경험하게된다. 이에본고에서는균형유지를위한신체움직임에대한개념이해와함께뇌질환이후균형능력을평가할수있는다양한방법들에대한고찰을통해뇌질환환자들의균형 교신저자 : 김은주, 서울시강북구삼각산로 58 142-884, 국립재활병원재활의학과 Tel: 02-901-1633, Fax: 02-901-1591 E-mail: silverzookim@gmail.com 본론 1) 균형유지에관여하는해부학적구조물균형유지를위해서는감각정보를정확히평가하는것뿐만아니라이에대한운동반응이적절하고효과적으로발생되는것이중요하며, 이를위해서는특정중추신경계구조물의기능이중요하다. 일차적으로균형조절을담당하는곳이소뇌 (cerebellum) 이다. 소뇌는대뇌피질, 기저핵 (basal ganglia), 척수소뇌로 (spinocerebellar tract), 소뇌핵 (cerebellar nuclei), 전정경로 (vestibular pathway) 로부터정보를받아다시대뇌피질, 기저핵, 시상, 4,5,6번뇌신경, 전정경로등으로정보를전달하여신체동작을할때근육들의적절한타이밍과협력을조절하게되며근육긴장도의조절을통해조화로운동작이가능하도록도와주는역할을수행한다. 3 기저핵역시균형유지를위한정보조절에중요한역할을하며대뇌피질, 소뇌에서정보를받아시상을통해운동피질로정보를전달함으로써운동대응전략과같은자동적자세 58
김은주 : 뇌질환환자의균형및자세평가 유지반응에대한역할을수행하여연속동작의움직임이부드럽고협응력이뛰어난움직임을가능하게한다. 그외에도전정핵 (vestibular nuclei) 을포함한뇌간 (brainstem) 은전정계에대한조절및보상적눈의움직임에관여함으로써균형조절의역할을담당한다. 3 2) 균형평가환자개인별로균형을유지하기위해사용을제한받는요소들과이를보상하는전략들이개별적이므로균형에문제가있는뇌질환환자들의균형능력평가를위해서는객관적인임상평가법을통해개인의균형능력을평가하는것뿐만아니라환자별뇌질환상태에대한이해가동반되는것이필수적이다. 즉, 발병시기, 질환의경증도, 병변부위, 인지및언어능력, 재활치료환경, 병전건강상태, 병전생활습관및기능수준등환자균형능력에대한포괄적인평가를우선적으로시행하는것을추천한다. 균형에대한평가는크게균형과연관이있는단독인자들을평가하는단인자요소 (single item component) 평가법또는균형과연관있는다양한인자다수를포함하는다인자기능 (multidimensional function) 평가법으로나눌수있다. 4 그이외의구분은다양한균형활동수행능력을측정하는방법에따르게되는데시간, 거리등을측정하는방법이거나서열화된점수 (ordinal scale) 로평가하는방법으로나눌수있다. 5 (1) 단인자요소평가균형에영향을줄수있는요인이나과정에대한평가로서관절가동범위, 근력, 시력, 전정기능과같은기본적인신경학적평가를통해체간이나하지의문제, 시력이나안구운동장애, 기저면에대한신체의정렬정도 (alignment) 등을파악해낼수있다. 6 앉거나서있는자세를얼마나오래유지하는가를측정하는방법은뇌졸중이나파킨슨병환자들에게자주사용되고있는방법으로다양한기립자세 (single stance, Rhomborg, tandem stance 등 ) 동안이거나눈을감거나뜨는시각감각사용여부에따른반응을함께평가하기도한다. 또다른방법인뻗기 (reaching) 평가는최대한환자가앞으로뻗어균형을유지할수있는거리를측정하는방법으로대부분동적기립균형능력을평가하기위한측정법이다. 이방법은원래노쇠 (frailty) 노인들을평가하기위한방법이었으나뇌졸중, 파킨슨병환자등에도사용되고있다. 변형된측정법으로반복뻗기검사 (repeated reach test) 는 60초이내에목표에도달할수있는횟수를재거나앉은자세에서의뻗기, 또는전방뻗기뿐만아니라후방, 측면뻗기동작도사용되기도한다. 이에더해상지거상 법 (arm raise test) 은정적균형능력을측정하는방법으로편마비뇌줄중환자의경우는비마비측상지를, 사지마비환자의경우는우세측상지를사용하여정해진시간내에상지거상횟수를측정한다. 7 전산화동적자세측정기 (Computerized Dynamic Posturography) 는감각기관검사 (sensory organization test, SOT) 를통해감각 ( 시각, 체성감각, 전정계 ) 기관기능, 중앙통합기전 (central integrating mechanism), 적절한대응전략선택, 운동반응의적절성및효율성등을구분하여평가할수있는방법으로감각기관검사, 운동조절검사 (motor control test, MCT), 적응력검사 (adaptation test) 등으로구성되어있다. 감각기관검사동안은환자의눈, 발, 관절에전달되는정보를 6가지로변화를줌으로써다양한감각적변동상황을재연하여개인별감각계의효율성을평가하고적절한대응반응이있는지를평가할수있으며, 운동조절검사는발판의전후방향으로의이동에따른자세반응능력을측정하여반응시간, 기울기등을측정하게된다. 8 이러한단인자요소평가법은측정하기쉽기때문에균형평가의선별검사로일반적으로사용되지만균형능력의하나의면만평가하기때문에치료계획을세울때에는제한성이있을수있다. 2 (2) 다인자기능평가다인자기능평가법은자세유지및균형고려되어야할많은요소들을합쳐균형기능수행에중점을두어개발된평가법으로, 다양한기능측면을평가하여하나의점수로합산된다는점에서유용하지만치료가필요한개별원인을구별해내는것이어려울수있다. 그러므로치료가필요한균형문제를구별해내기위해서는평가수행동안눈여겨보거나필요한단인자평가를추가로시행하는것이좋다. 2 가장널리사용되는방법인버그균형검사 (Berg Balance Scale, BBS) 는 14항목으로총점 56점으로원래노인대상으로만들어졌으나현재는다양한뇌질환환자들에게도사용되고있다. 각항목들은독립적이며특정시간이나거리를충족함에따라점수가산정되어지며측정시간은 15 20분정도소요된다. 3,9 Fugl-Meyer 운동평가는뇌졸중환자들의운동기능회복을평가하기위해고안된평가법으로이중균형관련 (Balance section of Fugl-Meyer Motor Assessment, FMA-B) 7가지항목 (0 14점) 을평가할수있다. 10 또한, 뇌졸중환자들의시간에따른운동기능평가의경과관찰이용이한운동기능평가Motor assessment scale (MAS) 의 8가지항목중앉은자세의균형능력을평가하는항목 (sit-mas) 을측정할수있다. 11 Postural Assessment 59
Brain& NeuroRehabilitation:2013; 6: 58~63 Table 1. Summary of the Measures of Balance Activity according to the Each Scales Activities BBS 9 FMA-B 10 BBA 14 PASS 12 Supine Supine to (non)affected side lateral Supine to sit up Sitting Supported sitting Sitting arm raise test Sitting forward reach test Sitting with back unsupported Sitting down Sit to stand Transfer from chair to chair Parachute reaction Standing Standing supported Standing arm raise test Standing forward reach test Standing unsupported Standing eye closed Standing feet together Standing one foot in front of the other 5 m walk test with an aid Weight shift test Step up test (sound/weak) Standing one leg Pick up slipper from floor Turn to look behind Turn 360 Feet alternating on stool BBS: Berg Balance Scale, FMA-B: Balance section of Fugl-Meyer Motor Assessment, BBA: Brunel balance assessment, PASS: Postural Assessment Scale for Stroke Patients. Scale for Stroke Patients (PASS) 는자세유지능력을평가하는측정법으로 12항목 0 3척도로구성되어있다. 12 Trunk impairment scale (TIS) 은뇌졸중후체간의운동능력을평가하기위한측정법으로앉은자세에서 17가지과제를통한균형능력을파악할수있다 (0 23점). 13 Brunel balance assessment (BBA) 는기존의평가방법과의달리균형능력에단계별과제를부여함으로써순차적인평가가가능하며환자의균형능력변화에따라반복적으로측정함으로써측정단계에따른임상적균형능력수준을가늠할수있는장점이있다. 14 상기평가법별검사방법에따른분류를정리한표는다음과같다 (Table 1). BBS는주로기립자세에서의균형능력을평가하고있으며, BBA는앉은자세및기립자세평가가균형있게포함되어있다. PASS는다른평가법에는포함되어있지않은누운자세균형평가가포함된다양한자세에서의균형능력을평가할수있다. 하지만, 이들검사들중 BBS는뇌질환환자들에대한임상해석이제한적이지만대체로긍정적으로제시되고있으나, 나머지검사들은좀더연구가필요한상태이며, 현재까지나온연구들을토대로뇌질환에따른각각의균형평가법당임상적으로의미있는변화 (minimal detectable change, MDC) 로볼수있는변화구간을살펴보면다음과같다. 뇌졸중의경우 BBS는타당도, 검사-재검사및검사자간신뢰도가높은편으로 MDC는 6점, TIS 역시신뢰도, 타당도가높은검사로 4점의변동을검사결과해석시의미를둘수있다. 또한 FMA-B 는 4점, 상지거상검사는앉은자세및기립자세에서 3회의변동이의미있다고볼수있으며, 전방뻗기검사는앉은자세 11 cm, 기립자세 7.5 cm의차이가의미있다고해석할수있다 (Table 2). 5 그외뇌질환의경우는뇌졸중에비해다소타당도및신뢰도가떨어지며임상적으로의미있는변화를측정할 60
김은주 : 뇌질환환자의균형및자세평가 Table 2. Summary of Psychometric Balance Properties in Stroke Components alidity Test-retest reliability Inter-tester reliability MDC Sitting forward reach test 17 + Sit MAS, BBS, FIM, 11 cm RMI Standing forward reach test 17 BBS, RMI 7.5 cm Sitting arm raise test 17 + BBS, Sit MAS, RMI 3 lifts Standing arm raise test 17 + BBS, RMI 3 lifts Step test 17 RMI 2 steps Step up test 17 BBS 18 1 stepup 6 FMA-B 10 BBA 14 Sit MAS 19-21 TIS 13 10 m walking test 22 6 min walking test 23 BBS, + RMI TUG, MAS, BI, FMA, FMA-B, FR + Sit MAS, FMA MAS, BBS, RMI + FMA=B, MAS BI, TCT ADL/IADL speed + TUG 24 gait, strength 4 1 4 0.15 m/s, 0.25 m/s 45 54 m MDC: Minimal detectable change, Sit MAS: Sitting section of Motor Assessment Scale, BBS: Berg Balance Scale, FIM: Functional Independence Measure, RMI: Rivermead Mobility Index, TUG: Timed Get Up & Go test, BI: Barthel Index, FMA: Fugl-Meyer Motor Assessment, FMA-B: Balance section of Fugl-Meyer Motor Assessment, TIS: Trunk Impairment Scale, TCT: Trunk control test, ADL: Activities of daily living. Table 3. Summary of Psychometric Balance Properties in Parkinson s Disease or TBI Components alidity Test-retest reliability Inter-tester reliability MDC Standing forward reach test 25 BBS (PD) 9 cm Standing arm raise test 25 + BBS, RMI, Sit MAS (PD) Step test 25 RMI (PD) 2 steps BBS 26,27 + disease severity (PD) 10 m walking test 22,28 6 min walking test 28 ADL/IADL (PD) ADL/IADL (TBI) speed (PD) TUG 27 gait, strength (PD) 0.18 m/s, 0.25 m/s TBI: Traumatic brain injury, MDC: Minimal detectable change, BBS: Berg Balance Scale, PD: Parkinson s Disease, RMI: Rivermead Mobility Index, Sit MAS: Sitting section of Motor Assessment Scale, TIS: Trunk Impairment Scale, BI: Barthel Index, UPDRS: Unified Parkinson s Disease Rating Scale, ADL: Activities of Daily Living, IADL: Instrumental Activities of Daily Living, TUG: Timed Get Up & Go test. 82 m 수있는연구들이제한적이었다. 그중파킨슨병환자의경우기립자세에서전방뻗기검사에서 9 cm, step test에서 2걸음차이가의미있는차이로볼수있다 (Table 3). 5 그외에도보행은복잡한균형수행과제이므로보행평가를통해서균형통합능력과이동 (mobility) 동안균형능력을평가할수있다. 가장보편적으로뇌질환환자들에게사용되고있는방법은 6분걷기, 10 m 걷기, Timed up and go test (TUG) 등이있다. 뇌졸중환자의경우는 10 m 걷기에서 0.14 0.24 m/s 변화, 6분걷기에서는 45 54 m 변화가있는경우를임상적으로의미있는변화로간주 할수있는데반해, 파킨슨병환자의경우는뇌졸중환자에비해더큰변화가필요하다 (Table 2, 3). 5 (3) 고찰환자의균형기능평가에있어개인별적용할평가방법선택을위해서는우선평가방법들의종류, 내용및장단점, 임상적의의등을잘이해하는것이필수적이다. 하지만아직평가법선택은이론적구조를바탕으로한다기보다임상의의경험에의해평가항목이나방법이선택되는것이일반적이다. 추후이론적배경을가지면서도임상친화적인균형평가들이개발되고대규모로적용되어진연 61
Brain& NeuroRehabilitation:2013; 6: 58~63 구들이진행되어근거를바탕으로임상에서합의점을추출해나가는과정이필요할것으로생각된다. 그와함께점수로평가되는평가법인경우에는항목들간의 단계 ( 순위 ) 가필요할것으로생각된다. 그렇게된다면어떤단계 ( 순위 ) 항목에서통과된다는의미는앞순위의항목들역시통과될것이기때문에평가시점매번모든측정항목들을시행하지않아도된다는장점이있다. 결과적으로환자는본인의균형상태에맞는몇가지항목만평가받으면되므로시간효율성이향상될수있다. 또한 단계 ( 순위 ) 점수가환자개개인의균형능력을대변할수있다. 예를들어버그균형검사점수가 46/56이라면어떤항목에서통과하였고실패하였는지에대한정보가포함되어있지않지만, 만약단계 ( 순위 ) 점수가 6단계라고한다면기존에정해둔과제 (1 6단계) 들은적어도수행가능함을의미하므로임상적으로균형기능을가늠하는데있어더정확한정보를제공받을수있을것이다. 하지만이러한 단계 ( 순위 ) 별평가법의원래의미를잘살리기위해서는반드시이론적배경및근거가제공되어야할것이다. 그리고, 뇌질환환자들의균형을평가하는데있어적용이용이하며특별한설비가필요하지않은다인자기능평가법들이임상에서흔히사용되고있지만앞서평가법별로정리한 Table 1을통해서도알수있다시피모든뇌질환환자들에게적용가능한완벽한평가가존재하는것이아니라평가법마다사용가능한환자군의특성이있다. 즉, 평가법마다천장 (ceiling) 또는바닥 (floor) 효과가존재할수있으므로환자의기능에맞는적절한평가법들을몇가지씩혼합해서사용한다면개별평가법이가지는단점을최대한줄일수있을것으로생각된다. 이에더해환자들의균형기능변동에대한임상적인해석에주의가필요할것으로생각된다. 즉, 뇌졸중환자의버그균형검사점수가 2점향상되었다면진정한균형능력향상으로해석할수있을까하는문제이다. 기능적변동인지정상적변동의범위인지에대한임상적해석에대한연구들이최근활발히진행되고있으므로추후지금까지보고된결과들이한층더성숙해질수있을것으로기대한다. 15,16 결론 뇌질환환자들의균형능력평가에객관적이면서신뢰성있는평가방법에대한필요성이크며현재까지많은평가법들이사용중에있다. 또한, 이러한평가를통해치료계획수립에영향을미치므로환자개개별균형능력에영향을미칠수있는다양한인자들의평가를통해적절한 균형능력평가법을선택하는것이중요하겠으며, 뇌질환환자들의자세및균형능력에대한평가및치료는복합적이므로균형기능을평가하는데있어포괄적인자세와이해가요구된다. 참고문헌 1) Tyson S, Watson A, Moss S, Troop H, Dean-Lofthouse G, Jorritsma S, Shannon M, Greater Manchester Outcome Measures P. Development of a framework for the evidencebased choice of outcome measures in neurological physiotherapy. Disabil Rehabil. 2008;30:142-149 2) Kim EJ. Balance in the elderly: physiologic and rehabilitation approach. Geriatirc Rehabilitation. 2011;1:29-33 3) Gillen G. Stroke Rehabilitation. A Fucntion-Based Approach. Philadelphia: Elsevier; 2011 4) Weerdesteyn, de Niet M, van Duijnhoven HJ, Geurts AC. Falls in individuals with stroke. J Rehabil Res Dev. 2008;45: 1195-1213 5) Tyson SF, Connell LA. How to measure balance in clinical practice. A systematic review of the psychometric and clinical utility of measures of balance activity for neurological conditions. Clin Rehabil. 2009;23:824-840 6) Tyson SF, DeSouza LH. A clinical model for the assessment of posture and balance in people with stroke. Disabil Rehabil. 2003;25:120-126 7) Duncan PW, Studenski S, Chandler J, Prescott B. Functional reach: predictive validity in a sample of elderly male veterans. J Gerontol. 1992;47:M93-98 8) Monsell EM, Furman JM, Herdman SJ, Konrad HR, Shepard NT. Computerized dynamic platform posturography. Otolaryngol Head Neck Surg. 1997;117:394-398 9) Berg KO, Wood-Dauphinee SL, Williams JI, Maki B. Measuring balance in the elderly: validation of an instrument. Can J Public Health. 1992;83 Suppl 2:S7-11 10) Beckerman, ogelaar TW, Lankhorst GJ, erbeek AL. A criterion for stability of the motor function of the lower extremity in stroke patients using the Fugl-Meyer Assessment Scale. Scand J Rehabil Med. 1996;28:3-7 11) Carr JH, Shepherd RB, Nordholm L, Lynne D. Investigation of a new motor assessment scale for stroke patients. Phys Ther. 1985;65:175-180 12) Benaim C, Perennou DA, illy J, Rousseaux M, Pelissier JY. alidation of a standardized assessment of postural control in stroke patients: the Postural Assessment Scale for Stroke Patients (PASS). Stroke. 1999;30:1862-1868 13) erheyden G, Nieuwboer A, Mertin J, Preger R, Kiekens C, De Weerdt W. The Trunk Impairment Scale: a new tool to measure motor impairment of the trunk after stroke. Clin Rehabil. 2004;18:326-334 14) Tyson SF, DeSouza LH. Development of the Brunel Balance Assessment: a new measure of balance disability post stroke. Clin Rehabil. 2004;18:801-810 15) Ries JD, Echternach JL, Nof L, Gagnon Blodgett M. Test- 62
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