Table 2. Overview of cognitive assessments.

Task	Description	Outcome measures	Targeted domain
Background assessment*
MOCA45	Screening of cognitive functions including visuospatial, attention, executive, memory, naming and orientation abilities.	Number of correct responses with a maximum score of 30	Overall cognitive abilities
TOPF-UK46	Participants are instructed to read out a list of 70 phonemically irregular words in ascending order of difficulty.	Number of correctly pronounced words.	Premorbid verbal IQ
Working memory updating
N-back47 auditory	Participants are instructed to press a key when an auditory letter stimulus is identical to N trials back (starting with 1-back, 2-back, etc). Participants complete 5 blocks of 20 trials after 1–2 practice sessions. Task difficulty (N-back level) is varied in response to participants’ performance level measured with the sensitivity index A’(48) as follows: If A’ > 0.9 then N+1 If 0.75 >A’ > 0.9 then N remains the same If A’ < 0.75 then N-1 (for blocks of N>1) If A’ < 0.65 in two consecutive 1-back blocks, then discontinue	Maximum N-back level attempted,Sensitivity index A’	Phonological working memory maintenance and updating
N-back visuospatial	Participants respond with a key press when the position of a blue square within a 3×3 grid is the same as N trials back under the same task conditions as above.	Maximum N-back level attempted,Sensitivity index A’	Visuospatial working memory maintenance and updating
Dual N-back (auditory and visuospatial)	Participants perform the auditory and visuospatial N-back tasks simultaneously as described above.	Maximum N-back level attempted,Sensitivity index A’	Working memory maintenance and updating,Attention switching, divided attention
Distractor suppression
Eriksen Flanker49	In each trial (160 in total), a target arrow is displayed in the centre of the screen pointing to the left or right. The target is flanked by arrows pointing in the same direction (congruent) or the opposite (incongruent) direction or by horizontal lines (neutral). Participants are instructed to respond to the target direction by pressing either the right or left shift key and ignore the flanker stimuli.	Reaction times in milliseconds,Accuracy rates for congruent, incongruent and neutral conditions	Interference suppression,Target facilitation
Stroop50	Participants are presented with a list of 112 colour words printed in incongruent ink colours. First, they are asked to read out the words (baseline), then to name the ink colour for each word (interference) as accurately and fast as they can within a 2 min time limit.	Number of correct responses, time to complete in seconds for baseline and interference conditions	Interference suppression
Attention switching
Verbal trails51	Participants are asked to count 50 digits upwards and recite 50 letters in alphabetical order (starting with A again when reaching Z) (baseline). They are then asked to switch between counting digits and reciting letters from the starting point 28-D and to switch between reciting letters and counting digits from the starting point R-13 for 25 trials each (50 in total) (switching).	Completion time in seconds,ErrorsSwitching cost (switching–baseline)	Attention switching,Divided attention
Cognitive flexibility
FAS verbal fluency52	Participants are asked to generate as many words as they can starting with the letters F, A and S within a time limit of 1 min per letter.	Number of correct words, repetition and intrusion errors.	Cognitive flexibility and fluency
Category Fluency52	Participants are asked to generate as many exemplars from the categories ‘animals’ and ‘supermarket items’ as they can within a time limit of 1 min per category.	Number of correct words, repetition and intrusion errors.	Cognitive flexibility and fluency
Processing speed
SDMT53	Participants are asked to match digits to symbols according to a key given to them by filling in rows of blank boxes underneath the target symbols with the corresponding digits within a time limit of 90 s.	Number of correct responses	Psychomotor speed, visuospatial attention, working memory

^*oOnly acquired at baseline for cognitive background information.

A’, alpha prime; MOCA, Montreal Cognitive Assessment; SDMT, Symbol Digit Modality Test; TOPF-UK, Test of Premorbid Functioning–UK edition