Table 3

Description of the tests and definition of parameters used in the analysis and thresholds (percentiles) for test performances

Tests	Description of the tests	Parameters used in the analysis	Theoretical performances	25th/75th percentile	10th/90th percentile	25th/75th percentile	10th/90th percentile
MMSE	Global scale measuring different cognitive components: orientation to time and place, registration of three words, attention and calculation, recall of three words, language, and visual construction.	Total score	0 to 30	24	22	−2	−3
WPTe	Verbal associative memory test, involving the reading of 10 word pairs. After reading the list, the examiner gives the first word of each pair and the subject is asked to provide the second word. Only one learning trial and a delayed recall are performed. Six of the word pairs are easy associations (eg, baby–cries) and four are difficult (eg, cabbage–pen). The easy pairs are given a score of 5 and the difficult ones a score of 10.	Scores to first recall of difficult (WPTd) and easy (WPTe) word pairs separately	0 to 40	0	0	−10	−10
WPTd			0 to 30	15	10	−5	−10
BVRT	Visual test consisting of 15 stimulus cards and 15 multiple choice cards. After presentation of a stimulus card for 10 s, the subjects were asked to choose the initial figure among four options.	Total score	0 to 15	9	8	−1	−2
FWT	A verbal episodic memory test based on five words. After semantic encoding, an immediate free recall is performed, followed by a semantic cued recall for forgotten words (eg: when ‘truck’ is forgotten, the semantic cue was ‘what was the name of the vehicle?’). After a non-verbal interference test (TMT A and B), a delayed recall is performed, including free and cued recalls.	Sum of the immediate and delayed free recalls	0 to 10	8	7	NA	NA
TMT A	Test measuring processing speed. Consists of connecting as fast as possible and in numerical order numbers (from 1 to 25) randomly located on a card. Before the test, a pre-test was given to ensure instructions had been understood. Contrary to the usual procedure, the psychologist allowed subjects to continue the task without any further help or rectification. Time was recorded independently of correct connections and errors.	Ratio of correct connections to the time of the TMT A	0 to ∞	2.92	3.67	+0.29	+0.71
IST	Test measuring the ability to generate words in four specific semantic categories (colours, animals, fruits, cities) in a limited time.	Number of words generated in each category in 60 s	0 to ∞	46	40	−6	−12
FTTp	Test measuring motor speed. The subject had to press a tapping key as many times as possible in 15 s. Two trials were performed: one with the preferred hand (FTTp) and one with the non-preferred hand (FTTnp).	Scores at the second trial for each hand	0 to ∞	60	51	−5	−9
FTTnp		Scores at the second trial for each hand	0 to ∞	53	47	−4	−7
STg	A card containing five columns of 10 sets of symbols (colour names: blue, red, yellow, green, printed in contrasting ink) was presented to the subject. He had to name the ink colour while ignoring the meaning of the word.	Numbers of good (STg) and bad answers (excluding corrected errors) (STb)	0 to 50	47	44	−1	−2
STb			0 to 50	1	3	0	+2
WST	The subject had to explain in what way two things were alike (eg ‘orange–banana’). Only the first five pairs of the WST were considered. Two points were given for an abstract generalisation and one point if a response was a specific concrete likeness.		1 to 10	5	3	0	−1

BVRT, Benton Visual Retention Test; FTTnp, Finger Tapping Test non-preferred hand; FTTp, Finger Tapping Test preferred hand; IST, Isaacs Set Test; MMSE, Mini-Mental State Examination; STb, Stroop bad answers; STg, Stroop good answers; TMT, Trail Making Test; WPTd, Wechsler Paired Test difficult items; WPTe, Wechsler Paired Test easy items; WST, Wechsler Similarities Test. For the TMT and STb, thresholds correspond to the 25th or 10th percentiles of the distribution as an increase in the value corresponds to a lowering in performance.