The Frail’BESTest. An Adaptation of the “Balance Evaluation System Test” for Frail Older Adults. Description, Internal Consistency and Inter-Rater Reliability

Figures & data

Table 1 English Version of the Frail’BESTest: Instructions and Evaluation

System	Test	Consign	Evaluation
A Anticipations	Rise to toes	“Give me your hands, rise on your toes and come back down, 3 times”	1: optimal postural preparation (anterior pelvic shift)
	Alternated foot reaching on a step	“Put your foot on the stair and go back on the floor, and with the other foot, repeat 2 times”	1: optimal postural preparation (lateral pelvic shift)
	Half-Turn preparation	“Please go straight on and turn around in front of this wall”	1: optimal postural preparation (the last foot support is oriented on the turn direction)
	Sit-to-stand	“Please Stand-up”	1: optimal trunk tilt (around 45–60° with vertical line)
	Back-to-sit	“Please sit-down”	1: optimal trunk tilt (around 45–60° with vertical line)
B Reactions	Postural adaptation	“I look for your reaction”	1: Optimal muscular contraction with the anterior muscular plan to counteract the anteroposterior light push
	Fall avoidance reaction	“I look for your reaction”	1: Optimal back step to counteract the anteroposterior heavy push
C Locomotion	Gait speed in dual task	“Please walk on this corridor, I am just behind you”	1: No notable gait-speed decrease, or instability
	Gait speed modulation	“Please try to walk faster, and now slower”	1: Ability to walk faster and slower
	Half-turn quality	This test can be assessed during the part A	1: No more than 4 steps are necessary to finish the half-turn
	Cervical rotation when walking	“Please walk on this corridor, I am on your side … ok now please turn the head to watch me, and now turn on the other side”	1: The patient turn the head with 45° of cervical rotation without slowdown or instability
	Go down to the floor	“Please sit down on the floor, you can use this chair to help yourself”	1: The patient sit down without human help (physical or verbal), securely
	Rise from the floor	“Please standup from the floor, you can use this chair to help yourself”	1: The patient stand up without human help (physical or verbal), securely
D Sensory orientation	Feet together/eyes open	“Please stay in this stand up position for a few seconds”	1: The patient is able to stay during 15 seconds in the position without important instability
	Feet shoulder width apart/eyes closed	Please stay in this stand up position for a few seconds”	1: The patient is able to stay during 15 seconds in the position without important instability
	Feet shoulder width apart on a foam surface/eyes open	Please stay in this stand up position for a few seconds”	1: The patient is able to stay during 15 seconds in the position without important instability
E Biomechanical constraints	Effort adaptation	No specific consign	1: The patient is not short of breath when he sit down after the gait speed test
	Lower limbs muscle power	Consign of the chair test: “please stand up and sit down successively, I will say when you will stop, you can use the armchairs if you need”	1: The patient is able to stand up and sit down three times in 15 seconds
	Ankle range of motion	No specific consign, patient is sit down, with 90° hip and knee flexion	1: passive and active range of motion of more than 10° in dorsal ankle flexion
	Foot quality state	No specific consign, no shoes	1: no problem on the feet, neither cutaneous nor osteoarticular deformities
	Directional instability	No specific consign, the patient is observed during the others tests	1: no preferential instability in one direction, for example backward, or laterally.
	Anterior stability limit (Functional Reach Test)	Consigns of the FRT (Duncan at al 1990): “Please reach forward as far as you can with your index finger without moving on your feet”	1: The patient is able to reach minimum 26 cm
F Gait Symmetry	Gait symmetry	No specific consigns, gait analysis during the gait speed test	1: Equal longer of each step
	Weight bearing pain	“Do you have pain when you charge one foot?”	1: No pain neither for the right nor for the left foot charge
	Strength deficit	No specific consign	1: The therapist evaluation find no strength deficit linked with the gait asymmetry
	Range of motion deficit	No specific consign	1: The therapist evaluation find no range of motion deficit linked with the gait asymmetry

Figure 1 English version of the Frail’BESTest.

Table 2 Comparisons Between BESTest and Frail’BESTest Items

Items in the BESTest	Items in the Frail’BESTest	Justification
Base of support	Foot quality state	Essential
Com alignment	Directional instability	Directional instability may be checked in static or dynamic balance
Ankle strength & range	Ankle range of motion And lower limbs muscle power	We choose to prioritize the ankle range of motion and the power of all the lower limb muscles with an adaptation of the chair test
Hip/trunk lateral strength	No	This analytic regional analysis had been removed by the functional analysis of Gait symmetry (Part F), that could highlight an impairment in hip stability
Sit on floor and standup	Go down to the floor and rise from the floor	Essential
Sitting verticality and lateral lean	No	We prioritized the functional reach forward test
Functional reach forward	Functional reach test forward	Essential
Functional reach lateral	No	We prioritized the functional reach forward test
Sit to stand	Adapted sit to stand	Use of hands allowed. We targeted the optimal trunk tilt in the evaluation criteria
Rise to toes	Adapted rise to toes	The patient takes the evaluator’s hands. We targeted the optimal postural preparation in the evaluation criteria
Stand on one leg	No	We prioritized the RISE TO TOES and the ALTERNATE STAIR TOUCHING
Alternate stair touching	Adapted alternate stair touching	The evaluator has a hands contact on the iliac bones. We targeted the optimal postural preparation in the evaluation criteria
Standing arm raise	No	We prioritized the RISE TO TOES and the ALTERNATE STAIR TOUCHING
In place response forward	No	We prioritized the Backward reactions
In place response backward	Postural adaptation	Essential
Compensatory stepping reaction forward	No	We prioritized the Backward reactions
Compensatory stepping reaction backward	Fall avoidance reaction	Essential
Sensory integration for balance	Sensory orientation	This test is adapted to assess both the visual-preference (eyes closed) and the foot-preference (foam surface) but we replaced the eyes closed/foam surface condition by the reduced polygon condition (feet together) as it is a frequent compensation.
Incline-eyes closed	No	We prioritized the SENSORY ORIENTATION
Gait – level surface	Gait speed test	The GAIT SPEED TEST has to be done along 10 meters before the Frail’BESTest examination
Change in gait speed	Gait speed modulation	Essential
Walk with head turns	Cervical rotation when walking	Essential
Walk with pivot turns	Half-turn quality and half-turn preparation	The HALF-TURN QUALITY is similarly evaluated by the stability and the number of steps and the HALF-TURN PREPARATION is focused on the postural preparation
Step over obstacles	No	We prioritized the other locomotor tests
Timed get up and go	No	We prioritized the other locomotor tests because the simple Timed Up and Go is a dual task for some patients with cognitive dysfunctions.
Timed get up and go with dual task	Gait speed in dual task	We use the GAIT SPEED IN DUAL TASK to compare with the normal GAIT SPEED
	Back-to-sit	This is an important test to spot the motor planning impairments
	Effort adaptation	This test allows to note a dyspnea in case of effort adaptation impairment
	Gait Symmetry and the associated weight bearing pain/strenght deficit/range of motion deficit	This section allows detecting a mechanical problem of pain/strength/range of motion potentially explaining gait asymmetry.

Figure 2 Patient distribution in center 1 and center 2.

Table 3 Characteristics of the 192 Non-Frail and Frail Patients Enrolled in Center 1

Parameters	Non Frail Mean (SD)	Frail Mean (SD)	P-value
N	82	110
Male/Female	34/48	31/79	P = 0.065
Age (years)	81.9 (5.4)	85.4 (4.9)	P<0.001
BMI	26.6 (5.1)	26.9 (4.9)	P=0.78
Walking velocity (m/sec)	0.80 (0.12)	0.47 (0.12)	P<0.001
Tinetti score	23.8 (3.3)	16.9 (3.9)	P<0.001
Frail BEST’Test score	20.0 (3.7)	13.5 (4.4)	P<0.001
Mini-motor test	18.6 (1.7)	14.8 (3.2)	P<0.001

Figure 3 Distribution of the scores obtained by the 192 patients for each test and descriptive data regarding distribution for the three tests (frail patients in the upper portion and non-frail patients in the lower portion). The black curve represents the theoretical normal curve extracted from the observed distribution. The table indicates means, standard deviations, medians and quartiles of each distribution regarding regarding frailty status. Skew and Kurt report the skewness and kurtosis of each distribution. *indicates significant parameters.

Figure 4 Presentation of the interrater reliability of the total Frail-BESTest Score in center 1 (A) and center 2 (B). Kendall’s tau coefficients for each system and each center (C).