Balance Evaluation Systems Test (BESTest)

BESTest is the quantitative assessment tool that aims to identify the disordered systems underlying the postural control responsible for poor functional balance. It was first developed by Dr. Horak in 2009 for clinicians to differentiate balance problems into six underlying systems that may constrain balance. It was developed from the theoretical understanding of balance control systems based on Bernstein's concept that postural control results from a set of interacting systems. It has 36 items that evaluate performance of 6 balance systems: bio-mechanical constraints, stability limits/verticality, anticipatory responses, postural responses, sensory orientation, and stability in gait.

Balance Evaluation Systems Test

Strength of BESTest

It incorporates different balance systems which help in postural control.
It helps clinicians to determine the type of balance problems so as to direct the specific treatments for their patients.
It will help to improve third party reimbursement by identifying the specific system affected and change with therapy.

Constraints of Postural Control Systems Addresses Following

Bio-mechanical Systems: Ankle strategy or compensatory steps for postural recovery (eg: flexed posture in frial elderly and Person's with Parkinson diseases).
Limits of Stability ( how far the body's center of mass can be moved over it's base of support) and Verticality (represent gravitational upright).
Anticipatory Postural Adjustments: Readiness prior to the voluntary movements which depend on interaction of supplementary motor areas with basal ganglia and brain stem areas.
Automatic Postural Responses: Impulses carried by short, medium and long proprioceptive feedback loops.
Sensory Orientation: Spatial orientation maintain by pathways involving vestibular system and sensory integrative areas of the temporo-parietal cortex.
Stability in Gait: Co-ordination between spinal locomotor and brain stem postural sensorimotor programs.

Intended Population

It can be used in varied age and severity of ambulator patients with neurological conditions ( Parkinson'ss, Stroke,Cerebellar Ataxia, Neuropathies, Head injury, Mulitiple Scelerosis, Cerebral palsy, etc.), Vestibular disorders, Cognitive Deficits and Elderly.

Method

Time to Administer

20-30 minutes.

Examiner Instructions for BESTest

Subjects should be tested with flat heeled shoes or with shoes and socks off.
If subject must use an assistive device for an item, score that item one category lower.

Equipment Required

Stop watch
Measuring tape mounted on wall for Functional Reach test
Approximately 60 cm x 60 cm (2 X 2 ft) block of 4-inch, medium-density, Tempur® foam
10 degree incline ramp (at least 2 x 2 ft) to stand on
Stair step, 15 cm (6 inches) in height for alternate stair tap
2 stacked shoe boxes for obstacle during gait  2.5 Kg (5-lb) free weight for rapid arm raise
Firm chair with arms with 3 meters in front marked with tape for Get Up and Go test
Masking tape to mark 3 m and 6 m lengths on the floor for Get Up and Go.

Scoring

It consist of 27 tasks, with 36 items in total. Each items is scored based on ordinal scale scoring from 0- 3 where 3 representing best performances and 0 representing worst performances. Scores for the total test is provided as a percentage of total points i.e. 108. In addition, 6 sub-systems scores can be generated separately in percentage of total score each representing a specific balance system.

Required Training

Reading Original Article/Manual.

Scoring Sheet

Here is the link for the scoring sheet of BESTest.

Psychometric Properties

For Non- Specific Patient Population

Reliability

The excellent inter- reliability of the total score with inter-class correlation (ICC) of 0.91 and subsection ICC ranged from 0.79 to 0.95:

Bio-mechanical constraints: 0.80
Stability limits/verticality: 0.79
Anticipatory Postural Adjustments: 0.92
Postural Reactions: 0.92
Sensory Orientation: 0.96
Stability of Gait: 0.88

Criterion Validity (Concurrent/ Predictive)

With Activities- Specific Balance Confidence (ABC) scale, it shows moderate correlation (r=.41–.78) where Stability Limits/Verticality scores had the best correlation (r=.78) and Anticipatory Postural Adjustments scores had the worst correlation (r=.41).
BBS, BESTest, Mini-BESTest, and Brief-BESTest were significantly correlated with each other with Spearman correlation coefficients (ρ=.83-.96) and with the ABC Scale (ρ=.46-.61).

Construct Validity

Control subjects scored significantly higher (better) than the subjects with balance problems (P=.036) via Mann-Whitney U test.
Discriminated between people with different balance deficits: subjects with unilateral vestibular loss scored the worst in Sensory Orientation (60%), whereas the subjects with Parkinson's scored the worst in Postural Responses (50%) and subjects with neuropathies in Anticipatory Postural Adjustment.

Minimal Detectable Change (MDC)

MDC at 95% confidence level= 9

Cut-off score

82% differentiate from fallers to non- fallers.

For Parkinson's

Reliability

Excellent inter-rater reliability of total BESTest with ICC 0.96 and subsection ICC ranging from 0.79-0.96.

Bio-mechanical constraints:0.81
Stability Limits/verticality: 0.79
Anticipatory Postural Adjustments: 0.91
Postural Responses: 0.91
Sensory Orientation: 0.96
Stability in Gait: 0.86

Excellent to Adequate Test- retest reliabilty for total score with ICC (0.88) and for subsection mentioned below:

Bio-mechanical constraints:0.69
Stability Limits/verticality: 0.63
Anticipatory Postural Adjustments: 0.83
Postural Responses: 0.87
Sensory Orientation: 0.72
Stability in Gait: 0.72

Cut-off Score:

To identify individual as fallers and non-fallers 69% cut-off score with sensitivity=0.84, specificity=0.76, LR+= 3.49, LR-=0.21AND AUC=0.85. [5]
With 69% of cut off score to detect fallers.

- with sensitivity of 0.84, specificity= 0.76, LR+=3.49, LR-= 0.21 and AUC= 0.84, adequate for detecting retrospective fallers.

- with sensitivity of 0.93, specificity= 0.84, LR+=5.81, LR-= 0.08 and AUC= 0.89, adequate for detecting prospective fallers.

- with sensitivity of 0.46 specificity= 0.74, LR+=1.77, LR-= 0.73 and AUC= 0.68, poor for detecting 12 months prospective fallers.

Criterion Validity:

Excellent Correlation between Mini-BESTest and BESTest total score (r=0.955).
Adequate Correlation with ABC (r=0.757).
Excellent Correlation with berg balance scale (r= 0.87)
Excellent Correlation with Functional Gait Assessment (r=0.882)

Limitations

The limitation of the BESTest is the time required to complete the assessment (35 minutes). Time to complete the assessment is longer with even longer depending upon the severity of conditions. A short form of the BESTest, the Mini-BESTest, and Brief-BESTest was developed to reduce the assessment time. Mini-BESTest has 14 tasks and needs only 10 to 15 minutes.
Equipment required is too many which may not be practical for regular use in all clinical settings.