*5.4. Reliability of the Assessments of the System and the Neurologists*

The values for the inter-rater agreement between the neurologists N1 and N2 (ICCN12) and among the neurologists and the system (ICCN12-SY) are shown in Table 10 (ρ values and 95% confidence intervals). According to [3], the ICC values less than 0.5, between 0.5 and 0.75, between 0.75 and 0.9, and greater than 0.90 are indicative of poor, moderate, good, and excellent reliability, respectively. In the evaluation of the ICCN12-SY for PSPIGD, we use the system evaluated PSCOM, stressing both the interpretation of PSCOM as a posture stability score and its good correlation with PSPIGD.

**Table 10.** Intra Class Correlations for the system and the neurologists assessment reliability.


<sup>a</sup> Significance level: *p* < 0.05.

The ICCN12 values, as reported in Table 10, indicate a generally good agreement between the two neurologists, with differences per task compatible with literature results. The results for ICCN12-SY show the system does not degrade significantly the inter-rater agreement between the neurologists, except for PSPIGD. This could be due to the limited number of subjects examined, or to the use of CoM parameters not completely superimposable to PIGD subscale assessments. In fact, CoM parameters are evaluated only in PSCOM task, e.g., during postural adjustments from the quiet stance and not in other more challenging dynamic domains of postural stability characterization [37].
