Assessment of reliability and validity of the mental chronometry task based on the box and block test in multiple sclerosis patients

Objectives:  Motor imagery (MI) is the visualization of action without its overt performance.  One of the measures of explicit MI is mental chronometry which  has  been  applied  to  multiple sclerosis (MS)  patients; nonetheless,   the  reliability  and  validity of this tool  has    been  never confirmed.  Therefore,  the present study aimed to assess the reliability and validity of mental chronometry in  MS  patients. Methods: A number of 60 MS patients who met the inclusion criteria were included in the present study via the census method. Thereafter, 20  MS  patients  were tested  via  mental  chronometry  based  on  the  box  and  block  test, as well as kinesthetic  and  visual  imagery  questionnaire-20 (KVIQ-20) in  two  sessions  with  a  10-day  interval.  Intra-class  correlation  coefficients  (ICCs)  were  calculated to determine  the  test-retest  reliability  of  mental  chronometry.  Pearson’s correlation analysis  was  used  to  evaluate  criterion  validity  with  the  KVIQ-20. Results:   The  test-retest  reliability  for  the  mental  chronometry  was  good  (ICCs: visual  analogue  scale=0.88, mean  execution  and  motor  imagery  absolute  difference= 0.75, imagery  duration=0.91, and execution  duration=0.97).  Moreover, the concurrent validity  between  the  visual  analogue  scale  of  mental  chronometry  and  KVIQ-20 was  good. Conclusion:  As evidenced by the results  of  the  present  study,  the  mental  chronometry based on box and block is  a  reliable  and  valid  tool  for the  assessment  of  motor imagery  in  MS patients.