Table 2.
Externally-paced tapping: timing metrics for each group, from ARMAX model.
| Control (N=31) | bvFTD (N=20) | svPPA (N=11) | naPPA (N=4) | AD (N=8) | ||
|---|---|---|---|---|---|---|
| Autocorrelation model statistics | ||||||
| Intercept (ms)a | Mean (SD) | 1474 (37.8) | 1480 (40.7) | 1483 (15.0) | 1507 (58.9) | 1490 (53.2) |
| Min, max | 1396, 1583 | 1384, 1570 | 1452, 1500 | 1447, 1567 | 1428, 1605 | |
| Drift (ms)b | N (%) negative drift | 9 (29) | 7 (35) | 4 (36) | 2 (50) | 2 (25) |
| Mean (SD) drift | 19 (32.3) | 10 (98.1) | 5 (25.4) | −86 (161.9) | 6 (40.4) | |
| Mean (SD) absolute drift | 29 (23.4) | 63 (74.5) | 19 (16.1) | 109 (142.3) | 30 (25.2) | |
| Mean (SD) negative drift | −17 (11.7) | −75 (106.5) | −20 (19.1) | −195 (175.7) | −49 (49.4) | |
| Mean (SD) positive drift | 34 (25.5) | 56 (54.6) | 19 (15.7) | 23 (9.8) | 24 (14.6) | |
| Modelled mean IRI (ms) | Mean (SD) | 1494 (9.2) | 1492 (36.3) | 1497 (3.8) | 1415 (157.3) | 1497 (8.8) |
| Min, max | 1455, 1506 | 1389, 1604 | 1490, 1503 | 1179, 1500 | 1485, 1511 | |
| Lag 1 autocorrelation | N (%) between -0.5 and 0 | 24 (77) | 15 (75) | 6 (55) | 2 (50) | 8 (100) |
| Mean (SD) | −0.33 (0.3) | −0.15 (0.20) | −0.45 (0.19) | −0.13 (0.44) | −0.24 (0.13) | |
| Min, max | −0.97, 0.34 | −0.51, 0.21 | −0.71, −0.07 | −0.59, 0.45 | −0.46, −0.08 | |
| Variances | ||||||
| Inter-response interval variance (ms2) | Mean (SD) | 11004 (9749) | 18,573 (20,812) | 5612 (6150) | 35,232 (22,763) | 9628 (6042) |
| Min, max | 600, 41,033 | 1566, 73,334 | 1290, 22,921 | 7946, 56,864 | 2393, 18,054 | |
| Clock variance (ms2) | Mean (SD) | 3403 (10,605) | 16,403 (26,946) | −212 (2338) | 27,710 (47,858) | 5256 (3937) |
| Min, max | −30,825, 40,306 | −160, 104,232 | −5623, 2830 | −10,098, 96,870 | 406, 11,654 | |
| Motor variance (ms2) | Mean (SD) | 3800 (6114) | 1085 (5653) | 2912 (4047) | 3761 (23,130) | 2186 (1716) |
| Min, max | −2470, 31,653 | −15,449, 12,918 | 236, 14,272 | −23,022, 33,481 | 696, 4777 | |
Abbreviations: SD, standard deviation; bvFTD, behavioural variant frontotemporal dementia; naPPA, nonfluent/agrammatic progressive aphasia; svPPA, semantic variant primary progressive aphasia; AD, Alzheimer׳s disease.
a
Note that the intercept for each participant is the first IRI for each participant, derived after having fitted the model across all taps for each participant. Thus the group means presented here are an indication of how well participants in each group, on average, judged the first tap.
b
Drift is the difference between first and last IRI.