This study aims to develop and validate the Italian version of the Motricity Index (MI-Italian), through the following steps:

• translation of the MI into Italian, by using the forward-backward translation approach, to produce a pre-final MI-Italian
• pre-pilot testing of the pre-final MI-Italian in a sample of ten health professionals (physicians and physiotherapists), who will be asked to judge the clarity of each item of the MI, including scoring instructions, to produce a final MI-Italian
• evaluation of the metric properties (internal consistency, inter- and intra-rater reliability, validity and responsiveness) of the final MI-Italian in a sample of subjects admitted to the Don Gnocchi Foundation in Florence for rehabilitation after stroke.

The Motricity Index (MI), developed by Demeurisse et al. in 1980, is an ordinal method for measuring motor impairment in post-stroke hemiparesis, focusing on muscle strength of proximal and distal muscle groups of upper and lower extremity. Since its introduction, it has been widely used. However, despite unofficial versions circulating in clinical settings, there is currently no validated Italian version of the scale. This study aims to develop this version and to evaluate its metric properties in a sample of subjects who had a stroke.

A pre-final MI-Italian will be produced following established international guidelines (forward-backward translation, each step involving two different translators). This version will be tested in a group of health professionals (physicians and physiotherapists) who will be asked to judge the clarity of each item of the scale, including scoring instructions, using a dichotomous response (clear/unclear). Items that are judged unclear by more than 20 percent of the professionals will be revised by the multidisciplinary translation team to produce the final MI-Italian.

The final MI-Italian will then be administered to a sample of at least 100 subjects with stroke to assess its metric properties. Participants will be enrolled among patients admitted to the Don Gnocchi Foundation in Florence for stroke rehabilitation. To assess reliability, upon admission each patient will be independently assessed using the MI-Italian by two examiners, drawn at random from a group of ten physiotherapists. One of the two raters will administer the scale twice on consecutive days. Other evaluators will administer other clinical scales (Fugl-Meyer assessment, FMA; modified Barthel index, mBI; modified Rankin scale, mRS) to assess the validity of the MI-Italian. All raters will be blinded to all other assessments and to their previous assessment, if any. All the scales will be administered again at discharge, when participants will also be asked to indicate the perceived change since admission in their ability to move and use the paretic limbs. For the latter, a 7-points Global Rating of Perceived Change (GRPC) Lickert scale will be used.

The Cronbach's alpha will be used to estimate the internal consistency of the scale. To assess intra-rater and inter-rater reliability, the Intraclass Correlation Coefficient (ICC1,1), Standard Error of the Measurement (SEM) and Minimal Detectable Change with 95% Confidence (MDC95) will be computed. Criterion and construct validity will be assessed by computing the association between the MI-Italian and the FMA, the mBI and the mRS, at both admission and discharge. For responsiveness, the following indices will be calculated: 1) Guyatt Responsiveness Index (GRI); 2) Standardized Response Mean (SMR), both in the whole sample and in subgroups of participants with different outcome (improved, unchanged, worsened) based on the GPRC; 3) Minimal Clinically Important Difference (MCID). The latter will be derived using the ROC curve approach, using the patient's perceived change in his/her ability to move and use the paretic limbs as an anchor.

The study is divided in two phases: A) pilot-testing of the pre-final MI-Italian, and B) verification of the metric properties (reliability, validity and responsiveness) of the final MI-Italian.

A) Pilot-test of the pre-final MI-Italian (verification of clarity of all items)

Inclusion criteria:

• being a physician or a physiotherapist with at least three years of experience in the functional assessment of subjects with stroke
• willingness to participate in the study

Exclusion criteria: none.

B) Study on the metric properties of the final MI-Italian

Participants (subjects who had a stroke): all subject consecutively admitted to the Don Gnocchi Foundation of Florence for rehabilitation after stroke (until the expected sample size is completed) who meet the following criteria.

Inclusion:

• age 18 years or older
• stroke outcomes such that they impact the person's ability to independently perform various basic activities of daily living
• willingness to participate in the study, with informed consent signed (by the support administrator/legal guardian, if necessary)

Exclusion:

• severe visual and/or auditory impairment that cannot be corrected
• cognitive impairment defined by a Mini Mental State Examination (MMSE) score <21;
• severe language impairment such that comprehension and performance of the task is prevented
• presence of signs of clinical instability, defined by a score greater than zero on the Clinical Instability Scale Raters: ten physiotherapists with at least three years of experience in the evaluation and treatment of subjects with stroke outcomes. Pairs of raters, equal in number to the number of patients enrolled, will be randomly drawn from this group, and each pair will be randomly assigned to a patient to be administered the MI-Italian Other examiners, also randomly drawn from the list of ten raters, will administer other clinical scales to participants to assess the validity of the MI-Italian.

A) In the pilot-testing, the pre-final MI-Italian will be tested for clarity on a sample of 10 health professionals (physicians and physiotherapists) working in stroke rehabilitation.

B) The metric properties of the final MI-italian will be tested on a sample of at least 100 patients who had a stroke. Considering a possible dropout rate of 15 percent, 115 subjects are expected to be enrolled.