Table 2. Correlation matrix of cognitive test scores’ pairwise correlation coefficients and univariable associations between visit day and mean (standard devation) of cognitive test scores.

	Pairwise Correlation Coefficents								Mean (SD) test scores
	LC1	DID1	IID2	NFC3	NFM3	NRC3	NRM3	LT4	Visit 1	Visit 2	p*
Letter cancellation (LC)1	1								18.9 (7.6)	26.3 (7.0)	<0.01
Direct image difference (DID)1	0.1890	1							1.4 (1.4)	2.3 (1.6)	<0.01
Indirect image difference (IID)2	0.1668	0.3137	1						1.6 (1.5)	2.3 (1.6)	<0.01
Forward number recall- total (NFC)3	0.1465	0.1775	0.2985	1					5.0 (1.4)	5.5 (1.5)	<0.01
Forward number recall- maximum digit span (NFM)3	0.1360	0.2228	0.2975	0.7235	1				4.1 (1.0)	4.3 (1.0)	0.04
Reverse number recall- total (NRC)3	0.0870	0.0885	0.2052	0.3310	0.2473	1			3.4 (1.8)	3.6 (1.6)	0.64
Reverse number recall-maximum digit span (NRM)3	0.1013	0.0234	0.2128	0.2208	0.1705	0.8440	1		3.2 (1.3)	3.3 (1.1)	0.41
Line trace (LT)4	0.2302	0.1049	0.0947	0.0704	0.0961	-0.0693	-0.0858	1	13.4 (7.8)	17.2 (6.0)	<0.01

Bold values indicate a significant association at α = 0.05

*p-value based on paired t-tests

Target skills assed by test:

¹visual attention

²visual memory

³short-term memory

⁴visuomotor skills