Table 1 Methodological quality assessment checklist

Internal validity

1: Measurements of motor function

Positive if measurement of motor function is effectuated with clinically relevant and validated tests

2: Clear presentation of fMRI parameters

Positive if MRI parameters are clearly described in the methods section

3: Description of additional medical and paramedical interventions

Positive if information on medical and paramedical treatment is reported

4: Mirror movement assessment

Positive if mirror movements during the fMRI session are assessed with e.g., EMG, kinematics, or visual inspection

5: Control of motor task performance

Positive if movement amplitude, frequency or range of motion are either standardized or measured during task execution

Statistical validity

6: Multiple comparisons correction

Positive if a correction for multiple comparisons has been applied to P-values for brain activity

7: Validity of applied statistics within and between subjects

Positive if applied statistical analyses within and between subject analyses are appropriate to the population and the study design

8: Combined fMRI and kinematic analysis

Positive if statistical tests are performed between fMRI and kinematic data

External validity

9: Specification of relevant patient characteristics

Positive if age, type of stroke, location, and number of strokes are specified

Technological validity

10: MRI strength

Positive if the strength of the magnetic field in Tesla is ≥ 3

11: fMRI spatial resolution

Higher scores correspond with higher spatial resolution of the fMRI sequence

12: fMRI temporal resolution

Higher scores correspond with a higher temporal resolution (TR: repetition time) of the fMRI sequence

13: Constraining character of the motion capture device

The lower the impact of the motion capture device on the ecological nature of the movement, the higher the score