Walking Stroop carpet: an innovative dual-task concept for detecting cognitive impairment

Figures & data

Figure 1A Illustration of the experimental condition in the “Walking Stroop carpet”.

Figure 1B First condition: DT_B&W.

Note: In that condition, the subject has to read and to walk on the word “yellow”.

Figure 1C Second condition: DT_Word.

Note: In that condition, the subject has to read and to walk on the word “yellow”.

Figure 1D Third condition: DT_Color.

Note: In that condition, the subject has to read and to walk on the color “green”.

Figure 2 Gait pattern Dendogram of the ST.

Notes: The cluster analysis consists in pairing the individuals based on the similarities of their overall gait parameters and in progressively grouping subjects until we have one group that gathers all the participants.
Abbreviations: Y, Young; O, Older; VO, Very Older; H, Healthy; BL, Borderline MCI; naMCI, non-amnesic MCI executive impairment only; aMCI, amnesic MCI; mdMCI, multiple-domain amnestic MCI.

Figure 3 Gait pattern Dendogram of the ST and WSC.

Notes: The figure is read from the bottom where the individual trials are listed, in two families, to top where all gait trials are grouped into a single family. The cluster analysis consists in pairing individuals based on the similarities of their overall gait parameters in dual-task condition (WSC), and in progressively grouping subjects until we have one group that gathers all the participants. The classification through this ascendant hierarchical method highlights a tree structure with two distinct branches brought together within a value of Euclidian distance smaller than 20 for a final merging higher than 50.
Abbreviations: Y, Young; O, Older; VO, Very Older; H, Healthy; BL, Borderline MCI; naMCI, non-amnesic MCI executive impairment only; aMCI, amnesic MCI; mdMCI, multiple-domain amnestic MCI.

Table 1 Number of errors in all conditions in DT

Walking test condition	Cluster group		P-value
	Group 1	Group 2
DTB&W	0.09 ± 0.3	0.09 ± 0.39	0.3
DTword	0.08 ± 0.32	0.03 ± 0.1	0.24
DTcolor	0.44 ± 0.85	0.19 ± 0.47	0.19
Total	0.2 ± 0.29	0.1 ± 0.28	0.12

Notes: Mean ± standard deviation, Student’s t-test. The values shown correspond to the average number of test errors for subjects in each group.

Abbreviation: DT, dual-task.

Figure 4 Results of analysis of variance (ANOVA) on gait parameters in each cluster group and walking test condition.

Note: *Significant difference for P-value < 0.05.

Table 2 Demographic and clinical characteristics of study participants stratified by cluster results

Variable	Cluster group		F; P-value
	Group 1 (n = 18)	Group 2 (n = 31)
Age (years) Y, O, VO (%)	O = 69.6 (57.2)	Y = 25 (45)	/
	VO = 79.9 (42.8)	O = 69.4 (32)
		VO = 79.4 (23)
Female (%)	n = 14 (77.7)	n = 24 (77.4)
Cognitive test
MMSE	27.9 ± 1.4	28.4 ± 0.9	1.9; 0.1
FAB	15.5 ± 1.5	17.3 ± 0.8	3.69; <0.001
WAIS (digit span forward and backward)	97.8 ± 1.35	99.4 ± 10.6	1.35; 0.5
Stroop I	84.3 ± 11.9	99.9 ± 15.8	1.75; 0.2
Stroop II	17.5 ± 10.5	107.4 ± 22.6	4.64; <0.0001
Stroop III	52.6 ± 6.4	57 ± 6.4	1.01; 1
Stroop interference	3.73 ± 7.4	0.34 ± 7.8	1.12; 0.8
TMT A	42.3 ± 11.1	27.2 ± 11.3	1.04; <0.0001
TMT B	100.16 ± 35.1	53.4 ± 22.9	2.34; <0.0001
Delta TMT (s)	57.8 ± 33.9	26.1 ± 15.3	4.91; <0.0001
Dubois five word-test	17.7 ± 3.1	19.1 ± 0.9	11.21; 0.02
Clock-drawing test	6.4 ± 0.7	6.5 ± 0.7	1.07; 0.4
IADL Part 1	7.3 ± 1.1	7.1 ± 2.6	1.37; 0.2
Mini GDS	0.7 ± 0.3	0.4 ± 0.4	1.15; 0.07

Note: Values are shown as the mean ± standard deviation.

Abbreviations: Y, young; O, old; VO, very old; MMSE, Mini Mental State Examination; FAB, Frontal Assessment Battery; WAIS, Wechsler Adult Intelligence Scale; TMT, Trail Making Test; IADL, Instrumental Activities of Daily Living; GDS, Geriatric Depression Scale.