parkinson s disease ( parkinson s ) is a progressive , chronic , neurodegenerative disease1 stemming from the atrophy of grey matter . it 
 is estimated that 10 million individuals around the world suffer from parkinson s , and this 
 figure is expected to double by the year 20302 . the prevalence of parkinson s ranges from 0.3% among individuals 
 aged less than 60  years to 1% among those aged 60 or older3 . the progressive nature of the disease causes both motor and 
 non - motor alterations . the main motor alterations are associated with the risk of falls , 
 which leads to a sedentary lifestyle and the reduction in activities of daily living exerts 
 a negative impact on clinical aspects1,2,3,4,5 . the main clinical manifestations of parkinson s are shaking , stiffness , slowness of 
 movement , postural alterations , and stooped gait , leading patients to adopt a flexed posture 
 due to the dominance of pro - gravitational muscles , with forward leaning of the head , the 
 chin tlited toward the thorax , kyphotic thorax , protracted shoulders , the arms rotated 
 internally , and , flexion of the hips , knees , and elbows , which projects the body forward , 
 compromising postural orientation and leading to impaired balance6 . all these postural changes , together with other 
 alterations , lead to postural instability , which is considered one of the main 
 characteristics of patients with parkinson s . this instability leads to a progressive 
 reduction in both static and dynamic balance , affecting one s ability to remain standing 
 without support or even sit down . researchers believe that postural instability is related to the loss of the capacity to 
 control intentional movements of the center of body mass on the support base during 
 activities that involve the transfer of weight . many individuals with parkinson s 
 demonstrate inadequate interactions among the vestibular , visual , and proprioceptive 
 systems , with consequent changes in the biomechanics of the body7 . the motor rehabilitation process for patients with parkinson s is normally directed toward 
 static and functional balance training to provide greater interactions with the surrounding 
 environment through treadmill training8 , 
 balance training involving virtual reality programs9 , the combination of dance and motor training10 , etc . a set of assessment measures to determine the 
 effects of particular interventions has been validated and reported in literature11 . assessment measures are important for 
 analysis of functional changes in all stages of the disease and are particularly sensitive 
 with regard to the evaluation of therapeutic intervention12 . the unified parkinson s disease rating scale ( updrs)13 , berg balance scale , timed up and go 
 test14 , six - minute walk test ( 6wmt ) , 
 10-meter walk test ( 10mwt)15 , and a force 
 plate to determine the center of pressure16 are among the measures used for the evaluation of balance . 
 moreover , a combination of different measures previously used in controlled clinical trials 
 is often employed . the aim of the present study was to perform a systematic review of the literature for the 
 analysis of different measures used in the evaluation of balance in patients with 
 parkinson s disease . the pubmed ( national library of medicine ) , bvs bireme , scielo , lilacs and pedro electronic 
 databases were searched for relevant studies addressing balance in patients with parkinson s 
 disease . for this purpose , the following combinations of keywords were used : parkinson s 
 disease and balance evaluation , parkinson disease and balance alterations , parkinson disease 
 and balance change , parkinson disease and change in balance , parkinson disease and balance 
 control and parkinson disease and postural control balance . the search was limited to 
 randomized controlled , clinical trials published in the previous five years ( inclusion 
 criteria ) . the searches initially led to the retrieval of 3,623 articles , 540 of which were 
 potentially eligible based on the inclusion and exclusion criteria . a total of 264 
 duplicates were removed , and 276 articles were excluded based on their titles and abstracts . the full texts of 84 articles were analyzed , with the inclusion of only those that met the 
 eligibility criteria and had a pedro score higher than four points . thus , 25 studies were 
 selected for the present systematic review ( fig . 
 1fig . table 1table 1.scores of articles included in literature reviewreferenceitemeligibility1- randomized allocation2- confidential allocation3- similar prognosis4- blinded subjects5- blinded therapists6- blinded evaluators7- key results8- intention to treat analysis9- comparison between groups10- precision and variabilityscoreabud qutubuddin et al . , 201521yyyynnyyyyy8/10natalie e. , allen et al . , 201022yyyynnnynyy6/10emma stack et al . , 201223yyyynnynnny5/10xian shen et al . , 20148yyyynnnyyyy7/10c . , tassorelli et al . , 201424yyyyy ynynyy8/10nima toosizadeh et al . , , 201428yynynnnyyyy6/10jos eduardo pompeu et al . , 20129yynynnyynyy6/10nan - yong lee et al . , , 201238yyyynnynyyy7/10y : yes ; n : no displays the pedro scores of the 25 studies that met the eligibility criteria 
 and were included in the present systematic review . diverse methods for the evaluation of 
 balance in individuals with parkinson s were used in studies with different intervention 
 protocols and comparisons between the experimental and control groups ( table 2table 2.characteristics of the studies included in the present systematic reviewauthors and year of publicationstudy designinterventionoutcomesabud qutubuddin et al . , 2013clinical trial forced exercise on stationary bike ( eg)1-updrs2-bbs3-finger taping test 4-pdq-39sara pires et al . , 2014clinical trial combination of musical auditory cues and regular 
 physical therapy ( eg)regular physical therapy alone ( cg)1-updrs2-bbs3-tug4-pdq-39chirs j.hass et al . , 2011clinical trial prt program ( eg)no intervention ( cg)1-frt2-tug3-updrsfuzhong li et al . , 2012clinical trial adapted tai chi programtree groups ; tai chi , resistance 
 training , and stretching1-isokinetic dynamometer2-gaitrite3-frt4-uprds5-tugfuzhong li et al . , 2012clinical trial technology - assisted balance and gait training ( eg)strengthening exercises ( cg)1-single - leg stance testnatalie e. allen et al . , 2010clinical trial minimally supervised exercise program 1-algorithm2-coordinated stability test3-sway meter4-bbs5-fog questionnaire6-sppb7-short -fes 8-pdq-39xian shen et al . , 2014clinical trial balance and gait training with enhanced feedback 
 ( eg)lower limb strength training ( cg)1-abc2-limits - of - stability test3-single - leg stance testc . 2014clinical trial injection of botulinum toxin type a + intensive program 
 ( eg)saline solution + intensive program ( cg)1-kinematic analysis of movement2-emg3-uprds4-vasnima toosizadeh et al . , 2014clinical trial electroacupuncture ( eg)sham treatment ( cg)1-sf-122-short - fes 3-mmse4-uprsalessandro picelli et al . , 2012clinical trialrobot - assisted treadmill training ( eg)treadmill 
 training alone ( cg)1-bbs2-abc3-tug4 - 10mwtnicola smania et al . , 2010clinical trial balance training ( eg)general physical exercises 
 ( cg)1-bbs2-abc3-postural transfer test4-cop5-uprds6-h&y7-staging scale8-gdsmohan ganesan et al . , 2013clinical trial tree groups : dopamine , dopamine + conventional treadmill 
 training , dopamine + pwstt1-updrs2-dynamic posturography3-bbs4-pomajos eduardo pompeu et al . , 2012clinical trial training performed with 10 wii fit games ( eg)balance 
 exercises ( cg)1-uprsnam - yong lee et al . , 2015clinical trialnds + fes + dance ( eg)nds + fes ( cg)1-bbs2-modified barthel index3-beck depression inventoryelisa pelosin et al . , 2010clinical trialphysical therapy + strategic video ( eg)physical therapy + video of 
 landscapes ( cg)1-fog questionnaire atefeh azarpaikan et al . , 2014clinical trial nft training period1-bbs2-ecg3-isokinetic dynamometer giuzeppe frazzitta et al . , 2014clinical trial intensive aerobic exercises ( eg)non - intensive exercises 
 ( cg)1-updrs2-bbs3 - 6wmtcolleen g. canning et al . , 2014clinical trial minimally supervised exercises pd webb ( eg)habitual 
 care ( cg)1-coordinated balance stability test2-fog questionnaire3-fes - i4-physical activity questionnaire5-sf-12v26-sf-6d7-pdq-39margaret schenkman et al . , 2012clinical trial supervised fbf and ae physical exercise program 
 ( eg)conventional at - home physical exercise ( cg)1-cs - pfp2-frt3-uprdrs4-pdq-39gustavo christofoletti et al . , 2010clinical trial balance and motor function stimulation exercise 
 protocol ( eg)1-bbs2-tuggao qiang et al . , 2014clinical trial yang - style tai chi exercise protocol ( eg)no 
 intervention ( cg)1-bbs2-tug3-updrsserene s paulo et al . , 2014clinical trial muscle strength training of legs with pneumatic 
 equipment ( eg)simulated low - intensity exercise ( cg)1-muscle strength2 - 10mwt3-tug4- single - leg stance testxia shen et al . , 2012clinical trialtraining with repetitive steps on preparatory visual 
 tracks ( eg)um - detook ( cg)1-uprds2-limits - of - stability test3-gaitriteryan p. duncan et al . , 2012clinical trial tango dance program ( eg)no intervention ( cg)1-uprds2- mini bestest3-fog questionnaire4 - 6wmt5 - 9hpt6-gaitrite ) . in the context of chronic neurological disorders , efforts are made to diminish physical 
 difficulties and allow affected individuals to perform activities of daily living with the 
 greatest possible efficiency and independence38 . thus , assessment tools and specific measures that address more 
 generic aspects , such as muscle strength , range of motion , functioning , and improvements in 
 quality of life , are needed for individuals with parkinson s . it is important for assessment 
 methods to analyze functional changes in all stages of the disease and to be particularly 
 sensitive in the evaluation of therapeutic interventions39 . among the specific parkinson s classification measures used in the studies analyzed , the 
 updrs is a validated scale that provides an objective perspective and allows the 
 classification of individuals with parkinson s . the updrs is also widely used by 
 physiotherapists for the evaluation of balance in clinical practice , as it has specific 
 items for the assessment of this characteristic . the scale was found to be precise and 
 sensitive according to the results of 14 articles analyzed in the present systematic review , 
 the study populations of wich were subject to different intervention protocols40 . the scale was validated for the 
 population with parkinson s and , in contains items for the assessment of balance . 41 conducted a study involving 24 
 patients with parkinson s allocated to two groups and assessed balance using the updrs . regarding the motor skills section of the scale , the authors found a significant improvement 
 in the experimental group ( dance ) in comparison with the control group ( conventional 
 physical therapy ) . eleven studies included in the present review used the berg balance scale for the 
 assessment of balance . each item is scored from 0 to 4 points , with a maximum score of 56 points . the points are 
 based on the time for which a position is held , the distance to which the upper limb is 
 capable of reaching out in front of the body , and the time required to complete each 
 task42 . this is a fast , precise 
 assessment tool for detecting changes in balance among individuals with parkinson s . in a 
 previous systematic review with meta - analysis , chih - hsuan chou et al . 43 found that a reduction in the gait velocity score on the 
 berg balance scale was correlated with impairment regarding the performance of activities of 
 daily living . the timed up and go test is used to quantify functional mobility based on the time ( in 
 seconds ) required to perform the task of standing up from a chair ( seat approximately 46 in 
 height and armrests 65  cm in height ) , walking three meters , turning around , returning to the 
 chair , and sitting down again42 . the 
 population studied , the timed up and go test is a good predictor of the risk of falls . although it was not specifically designed for the assessment of balance , the importance of 
 this measure to the evaluation of dynamic balance related to mobility was evident in the 
 studies analyzed in the present review . in a systematic review with meta - analysis involving 
 53 studies , 44 found that 
 the timed up and go test was a sensitive assessment tool for the evaluation of gait 
 stability and balance in more than 50% of the studies , which is in agreement with the 
 findings of the present systematic review . a large portion of the studies employed three or more assessment tools , which were always 
 accompanied by tests and equipment . several studies have addressed the use of assessment 
 measures for the evaluation of balance among individuals with parkinson s with the aim of 
 designing interventions that favor an improvement in quality of life and a reduction in the 
 risk of falls . thus , the studies analyzed evaluated individuals in a complex fashion with 
 functional approaches that were adaptable to the needs of such patients . the present review shows that a variety of different assessment tools are used for the 
 evaluation of balance in patients with parkinson s disease , such as scales , tests , and 
 equipment . the majority of studies employed more than one measure , and there is no consensus 
 regarding a single , precise assessment tool for the evaluation of balance in this 
 population .
[ purpose ] the present literature review was conducted on the use of different measures 
 for the evaluation of balance in patients with parkinson s disease . 
 [ materials and 
 methods ] the pubmed , bireme , scielo , lilacs , and pedro electronic databases were searched 
 for relevant studies . [ results ] 
 the searches initially led to the retrieval of 3,623 
 articles , 540 of which were potentially eligible after limiting the search to clinical 
 trials published in the last five years . 
 a total of 264 duplicates were removed , and 276 
 articles were excluded based on their titles and abstracts . 
 the full texts of 84 articles 
 were analyzed , and only those with a pedro score higher than four points ( n=25 ) were 
 included in the review . 
 [ conclusion ] different methods , such as scales , tests , and 
 equipment , are used for the evaluation of balance in patients with parkinson s disease . 
 more than one measure has been employed in most studies , and there is no consensus on a 
 single precise measure for the evaluation of balance in this population .