Characteristics of the included studies.

Abbreviations: BAI – Beck Anxiety Inventory; BDI – Beck Depression Inventory; CES-D - Center for Epidemiological Studies Depression Scale; d2CP – Brickenkamp d2 test concentration performance; FSS – Fatigue Severity Scale; MAS – Modified Ashworth Scale; MFI – Multidimensional Fatigue Inventory; MFIS – Modified Fatigue Impact Scale; MS – multiple sclerosis; MSIS-29v2– Multiple Sclerosis Impact Scale-29, version2; MSQOL54 - Multiple Sclerosis Quality of Life 54; NA – Not assessed; NAB – Neuropsychological Assessment Battery; NR – not reported; NS – not significant; PASAT – Paced Auditory Serial Addition Test; POMS – Profile of Mood States; SF-36 - Short Form-36 Health Survey; SSS – Stanford Sleepiness Scale; STAI – State Trait Anxiety Inventory; TOL – Tower of London Test. Characteristics of the included studies.