Construct Validity of the Both Hands Assessment Using Wrist-Worn Accelerometers

Figures & data

Figure 1. Participant flow chart.

Table 1. Sample characteristics.

Variable	Group (n = 44)
Age (years), mean (SD); range	9.1 (1.6); 6–12
Sex (female), n (%)	17 (38)
MACS, n (%)
I	18 (34)
II	28 (50)
III	9 (16)
GMFCS, n (%)
I	13 (30)
II	14 (32)
III	11 (25)
IV	6 (13)
Primary motor type, n (%)
Spastic	36 (82)
Dyskinetic	5 (11)
Hypotonic	1 (2)
Ataxic	2 (4)
Dominant hand, n (%)
Right	26 (59)
Left	15 (34)
Mixed	3 (7)
Asymmetric hand use (Yes), n (%)	8 (18)

MACS: Manual Ability Classification Scale; GMFCS: Gross Motor Function Classification Scale; BoHA: Both Hands Assessment; Asymmetric hand use = BoHA percentage difference between hands ≥ 20%.

Table 2. Mean both hands (BoHA) assessment units and mean activity counts by manual ability classification scale (MACS) level, BoHA Each-Hand Sub-scores and mean activity counts for the dominant and non-dominant hand by MACS level and BoHA percentage difference between hand and mean activity asymmetry index by MACS level.

		MACS level
		I (n = 15)	II (n = 22)	III (n = 7)
Measure		Mean (SD)	Mean (SD)	Mean (SD)
Both hands	BoHA units^#	86.7 (7.7)	66.9 (11.3)	51.9 (4.8)
	Sum of mean activity^#	142.2 (27.9)	119.2 (26.1)	105.7 (29.3)
Dominant hand	BoHA each hand sub-score	42.9 (0.35)	38.1 (1.0)*	33.9 (2.1)*
	Mean activity	74.0 (3.7)	66.3 (3.1)*	71.2 (7.8)*
Non-dominant hand	BoHA each hand sub-score	42.3 (0.43)	34.2 (1.6)	23.3 (1.3)
	Mean activity	68.3 (4.1)	52.8 (4.4)	34.5 (4.8)
Comparing hands	BoHA percentage difference between hands^#	2.5 (2.6)	11.0 (14.3)	29.3 (16.2)
	Mean activity asymmetry index^#	7.1 (6.9)	19.3 (17.7)	35.3 (14.7)

MACS: Manual Ability Classification System; BoHA: Both Hands Assessment; ‘mean activity’: mean accelerometry counts per second during BoHA assessment; ^#One-way ANOVA: significant difference between MACS levels, p < 0.05; *Paired t-test: significant difference between dominant and non-dominant hand within MACS level, p < 0.05.

Figure 2. (a) Association between BoHA units and total mean activity. (b) Association between BoHA Each-Hand Sub-score and mean activity by limb. (c) Association between the mean activity and BoHA asymmetry indexes of X children with bilateral cerebral palsy.

Data availability statement

Data of this study are available on request from the authors.