Table 4.
Properties of Hevelius computer mouse task features and models
| Sensor | Feature name | Relationship with SARA (BARS) | Relationship with PROM-Ataxia | Test–retest reliability | Disease versus control | |||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Total | Arm subscore (FNF) | Total | Arm subset | |||||||||
| r | P-value | r | P-value* | r | P-value | r | P-value | ICC | P-value | es | ||
| Hevelius (single features) | Movement time | 0.84 (0.83) | 9.0E-09 | 0.61 (0.73) | (6.0E-06) | 0.67 | 2.0E-04 | 0.68 | 4.0E-05 | 0.99 | 2.0E-03 | 2.0 |
| Movement time (CV) | 0.85 (0.86) | 8.0E-09 | 0.66 (0.73) | (6.0E-06) | 0.71 | 2.0E-04 | 0.73 | 3.0E-05 | 0.94 | 2.0E-03 | 1.7 | |
| Execution time | 0.83 (0.81) | 3.0E-08 | 0.56 (0.69) | (3.0E-05) | 0.67 | 2.0E-04 | 0.68 | 4.0E-05 | 0.99 | 2.0E-03 | 1.9 | |
| Execution time (CV) | 0.82 (0.83) | 2.0E-08 | 0.69 (0.75) | (4.0E-06) | 0.68 | 2.0E-04 | 0.72 | 3.0E-05 | 0.92 | 9.0E-03 | 1.3 | |
| Execution time without pauses | 0.76 (0.74) | 8.0E-07 | 0.46 (0.59) | (6.0E-04) | 0.63 | 3.0E-04 | 0.60 | 5.0E-04 | 0.97 | 2.0E-03 | 1.8 | |
| Execution time without pauses (CV) | 0.79 (0.82) | 9.0E-08 | 0.73 (0.77) | (2.0E-06) | 0.65 | 2.0E-04 | 0.72 | 3.0E-05 | 0.84 | 2.0E-03 | 1.9 | |
| Verification time | 0.45 (0.47) | 9.0E-03 | 0.47 (0.46) | (1.0E-02) | 0.43 | 2.0E-02 | 0.40 | 3.0E-02 | 0.89 | n.s. | - | |
| Verification time (SD) | 0.75 (0.76) | 2.0E-06 | 0.66 (0.73) | (6.0E-06) | 0.59 | 6.0E-04 | 0.58 | 8.0E-04 | 0.96 | 2.0E-03 | 1.7 | |
| Number of pauses | 0.82 (0.82) | 3.0E-08 | 0.69 (0.78) | (2.0E-06) | 0.62 | 4.0E-04 | 0.69 | 4.0E-05 | 0.97 | 2.0E-03 | 2.0 | |
| Duration of longest pause | 0.82 (0.81) | 3.0E-08 | 0.69 (0.78) | (1.0E-06) | 0.61 | 4.0E-04 | 0.68 | 5.0E-05 | 0.97 | 2.0E-03 | 2.0 | |
| Max speed | - | n.s. | - | n.s. | - | n.s. | - | n.s. | 0.95 | n.s. | - | |
| Max speed (CV) | 0.72 (0.76) | 4.0E-06 | 0.54 (0.62) | (3.0E-04) | 0.52 | 3.0E-03 | 0.59 | 7.0E-04 | 0.85 | 2.0E-03 | 1.8 | |
| Max acceleration | - | n.s. | - | n.s. | - | n.s. | - | n.s. | 0.95 | n.s. | - | |
| Max acceleration (CV) | 0.56 (0.60) | 9.0E-04 | 0.44 (0.49) | (6.0E-03) | 0.37 | 4.0E-02 | 0.43 | 2.0E-02 | 0.80 | 5.0E-03 | 1.3 | |
| Normalized jerk | 0.80 (0.80) | 7.0E-08 | 0.56 (0.67) | (5.0E-05) | 0.67 | 2.0E-04 | 0.69 | 3.0E-05 | 0.98 | 3.0E-03 | 1.9 | |
| Normalized jerk without pauses | 0.75 (0.75) | 2.0E-06 | 0.46 (0.59) | (6.0E-04) | 0.61 | 4.0E-04 | 0.62 | 3.0E-04 | 0.97 | 2.0E-03 | 1.9 | |
| Click duration | 0.75 (0.68) | 2.0E-06 | 0.51 (0.64) | (2.0E-04) | 0.53 | 3.0E-03 | 0.47 | 7.0E-03 | 0.96 | 2.0E-03 | 1.6 | |
| Click duration (SD) | 0.67 (0.61) | 3.0E-05 | 0.40 (0.52) | (4.0E-03) | 0.49 | 6.0E-03 | 0.44 | 2.0E-02 | 0.82 | 2.0E-03 | 1.3 | |
| Movement direction changes | 0.45 (0.47) | 9.0E-03 | - | n.s. | 0.37 | 4.0E-02 | 0.44 | 2.0E-02 | 0.93 | 3.0E-03 | 1.8 | |
| Orthogonal direction changes | 0.61 (0.60) | 3.0E-04 | 0.34 (0.48) | (8.0E-03) | 0.50 | 5.0E-03 | 0.56 | 2.0E-03 | 0.95 | 5.0E-03 | 1.4 | |
| Task axis crossings | 0.47 (0.49) | 7.0E-03 | 0.28 (0.38) | (3.0E-02) | 0.42 | 2.0E-02 | 0.48 | 6.0E-03 | 0.89 | 2.0E-03 | 1.7 | |
| Max deviation from task axis | 0.55 (0.55) | 2.0E-03 | 0.28 (0.40) | (3.0E-02) | 0.48 | 6.0E-03 | 0.50 | 4.0E-03 | 0.93 | n.s. | - | |
| Movement error | 0.59 (0.59) | 5.0E-04 | 0.33 (0.43) | (2.0E-02) | 0.54 | 3.0E-03 | 0.56 | 2.0E-03 | 0.94 | n.s. | - | |
| Movement offset | 0.58 (0.58) | 5.0E-04 | 0.31 (0.41) | (3.0E-02) | 0.49 | 5.0E-03 | 0.48 | 6.0E-03 | 0.85 | n.s. | - | |
| Movement variability | 0.56 (0.56) | 1.0E-03 | 0.30 (0.41) | (3.0E-02) | 0.50 | 5.0E-03 | 0.52 | 3.0E-03 | 0.94 | n.s. | - | |
| Distance from target at end of main SM | 0.79 (0.81) | 9.0E-08 | 0.59 (0.69) | (3.0E-05) | 0.66 | 2.0E-04 | 0.69 | 4.0E-05 | 0.95 | 2.0E-03 | 2.2 | |
| Target re-entries | 0.71 (0.73) | 6.0E-06 | 0.55 (0.64) | (2.0E-04) | 0.64 | 3.0E-04 | 0.71 | 3.0E-05 | 0.93 | 2.0E-03 | 1.9 | |
| Click slip | 0.45 (0.42) | 9.0E-03 | - | n.s. | - | n.s. | - | n.s. | 0.86 | 2.0E-02 | 1.2 | |
| Fraction distance covered in main SM | 0.42 (0.48) | 2.0E-02 | - | n.s. | 0.41 | 2.0E-02 | 0.49 | 6.0E-03 | 0.82 | 3.0E-02 | 1.0 | |
| Fraction of main SM spent accelerating | 0.50 (0.48) | 3.0E-03 | 0.39 (0.39) | (3.0E-02) | 0.51 | 4.0E-03 | 0.48 | 6.0E-03 | 0.84 | n.s. | - | |
| Number of submovements | 0.55 (0.58) | 2.0E-03 | 0.53 (0.55) | (2.0E-03) | 0.46 | 8.0E-03 | 0.56 | 2.0E-03 | 0.96 | 2.0E-02 | 1.1 | |
| Main submovement | 0.56 (0.60) | 9.0E-04 | 0.32 (0.39) | (3.0E-02) | 0.51 | 4.0E-03 | 0.60 | 5.0E-04 | 0.83 | n.s. | - | |
| Noise to force ratio | 0.74 (0.73) | 2.0E-06 | 0.53 (0.63) | (2.0E-04) | 0.60 | 5.0E-04 | 0.54 | 2.0E-03 | 0.94 | 2.0E-03 | 1.7 | |
| Hevelius (models) | BARS total prediction model | 0.85 (0.84) | 2.0E-10 | 0.58 (0.71) | (3.0E-06) | 0.67 | 2.0E-05 | 0.70 | 5.0E-06 | 0.98 | 9.0E-05 | 2.2 |
| BARS arm prediction model | 0.87 (0.85) | 4.0E-11 | 0.59 (0.72) | (2.0E-06) | 0.69 | 8.0E-06 | 0.70 | 4.0E-06 | 0.98 | 2.0E-04 | 2.1 | |
| UPDRS total prediction model | 0.88 (0.86) | 5.0E-12 | 0.65 (0.75) | (4.0E-07) | 0.73 | 1.0E-06 | 0.72 | 2.0E-06 | 0.99 | 4.0E-04 | 1.8 | |
| UPDRS arm prediction model | 0.80 (0.79) | 2.0E-08 | 0.62 (0.70) | (4.0E-06) | 0.64 | 5.0E-05 | 0.63 | 6.0E-05 | 0.98 | 3.0E-04 | 1.8 | |
| Pairwise comp total prediction model | 0.83 (0.82) | 2.0E-09 | 0.60 (0.71) | (3.0E-06) | 0.68 | 2.0E-05 | 0.71 | 3.0E-06 | 0.97 | 3.0E-05* | 2.5 | |
| Pairwise comp arm prediction model | 0.81 (0.81) | 5.0E-09 | 0.66 (0.75) | (3.0E-07) | 0.63 | 7.0E-05 | 0.66 | 2.0E-05 | 0.96 | 2.0E-05* | 2.7 | |
| Ataxia versus controls prediction model | 0.73 (0.71) | 2.0E-06 | 0.53 (0.65) | (4.0E-05) | 0.48 | 5.0E-03 | 0.53 | 2.0E-03 | 0.95 | 2.0E-05* | 4.0 | |
Relationships with ataxia rating scales and patient-reported function, test–retest reliability, and disease versus control statistics are provided. Key features/models are bolded. Features that were significantly different between preataxic individuals and controls are marked in the disease versus control P-value column with an (*). Relationships that are not significant are labelled as ‘n.s.’. The P-values reported for the relationships with the ataxia rating scale arm subscore are for the BARS arm subscore as these relationships were stronger than the SARA arm subscore relationships. BARS, Brief Ataxia Rating Scale; CV, coefficient of variation; es, effect size; FNF, finger–nose–finger; ICC, intraclass correlation coefficient; PROM-Ataxia, Patient-Reported Outcome Measure of Ataxia; r, Pearson correlation coefficient; SARA, scale for the assessment and rating of ataxia; SD, standard deviation; SM, submovement; UPDRS, Unified Parkinson’s Disease Rating Scale.