Accuracy of Motor Performance Perception in Multiple Sclerosis

Perceptive Sensitivity

Ratio between participants' reporting frequency and actual variability in motor performance (e.g., gait and sit-to-stand \[STS\]), referred to as the 'Detection-rate.' Number of pinches is divided by the Coefficient of Variability (in %, of speed or smoothness parameter) in the studied time-window.

Detection Accuracy

Accuracy of detecting naturally occurring variations in self-paced gait and sit-to-stand (STS) performance. Objective change points (events) in speed/smoothness are identified using peak detection algorithms with a predefined threshold to extract only perceptually meaningful speed/smoothness fluctuations. Participants indicate perceived changes using a pinch gesture. A response is classified as correct if it occurs within a ±2-second window of a detected event. Responses outside this window or unmatched with any event are incorrect. Perceptive accuracy is modeled as a binary variable (correct/incorrect) and analyzed using mixed-effects logistic regression to account for repeated measures within subjects.

Correspondence Accuracy

Intra-subject correlation between perceived and actual imposed variations in walking speed or seat height, across different difficulty levels. Pearson correlations will study the linear relationship between the exercise difficulty and the reported difficulty. A Fisher Z transformation is carried out on all correlations before further analysis (group level comparisons across participants). -Detailed Picture of Each Phase: Average exercise difficulty and reported difficulty are calculated for every 30 s (or 3 STS repetitions). Multiple mixed model analyses are performed on the phases separately, with exercise difficulty and reported difficulty as dependent variables in separate analyses. Group (patient versus controls) and time are used as independent variables in all analyses. To control for potential baseline differences in any of the outcome variables exercise and reported difficulty in the last 30 s of the baseline phase are added as covariates in the analyses.

Confidence Rating

A short structured interview follows the experimental tasks of Day 1 and Day 2, including the following question: "On a scale from 0 to 100, how certain are you that you have been precise/accurate in detecting ongoing variations in your performance? Please mark your confidence level on the presented visual scale". Higher values representing higher confidence (subjective beliefs on their perceptive accuracy).

Perceptive Awareness

Degree of correspondence between participants' subjective confidence ratings and actual perceptual accuracy in detecting motor performance changes. To obtain a crude measure of perceptive awareness, we use two complementary approaches. First, we calculate a confidence-accuracy gap for each participant by subtracting their objective task accuracy from their retrospective confidence rating (in %). Positive values indicate overconfidence, while negative values indicate underconfidence. Second, to assess metacognitive awareness at the group level, we computed the correlation between participants' confidence ratings and their task accuracy. This group-level analysis provides an estimate of whether individuals who were more accurate also tended to be more confident or if there are specific trends differing between groups.

Interoceptive Sensibility

Participants' self-reported (subjective) beliefs about their interoceptive abilities is assessed using the Multidimensional Assessment of Interoceptive Awareness (MAIA-2). This scale is a self-report questionnaire to measure multiple dimensions of interoception: 8 different subscales, each averaging the items scores ranging from 0-5 (higher scores representing higher reported interoceptive abilities).

Proprioceptive Sensibility

Self-reported awareness of body posture consisting of 12 items, and with a total score ranging from 12 to 84, with higher scores representing higher reported postural awareness.

Visual Analogic Scale for Fatigue

Self-reported fatigue levels assessed using a Visual Analog Scale (VAS) ranging from 0 ('not at all fatigued') to 10 ('extrimely fatigued'), measured before and after each experimental session (eg. 6MWT or STS experiments).

Hospital Anxiety and Depression Scale (HADS)

A two dimension scale (7 items subscale Depression, 7 items subscale Anxiety) developed to identify depression and anxiety among physically ill patients. Total score: 0-42. Higher scores represent higher Anxiety or depression.

Positive and Negative Affect Schedule (PANAS)

Brief scale to administer to assess positive and negative affect with 2 subscales of 10 items each. Range score is 10-50 for each subscale. Higher scores in each subscale represent higher positive (or negative) affect.

Fatigue Scale for Motor and Cognitive Functions (FSMC)

A 20-item questionnaire assessing how fatigue impact on quality of life. Fatigue severity scores range from 1 (Does not apply at all) to 5 (Applies completely), with higher scores indicating more severe fatigue and greater impact on daily activities.