Table 2.
Specific neuropsychological tests: digit and letter span forward
| Onset | 6 months | 14 months | 24 months | Controlsa, mean score (SD) | |
|---|---|---|---|---|---|
| Auditory digit span | 6.8 (94) | 6.0 (91) | 6.2 (92) | 7.0 (95) | 5.28 (1.15) |
| Visual digit span | 6.0 (88) | 6.2 (90) | 6.4 (91) | 8.0 (97) | 5.38 (1.34) |
| Auditory letter span | 4.4 (11) | 5.2 (78) | 6.0 (89) | 5.6 (83) | 4.9 (0.74) |
| Visual letter span | 5.4 (74) | 6.2 (90) | 6.2 (90) | 6.0 (89) | 5.2 (1.07) |
| Visual memory span (WMS-R) | 6.0 (90) | 6.5 (96) | 6.5 (96) | 5.5 (74) | 5 (56 percentile)b |
Data are presented as raw score (percentile) unless otherwise indicated.
a
Healthy controls (n = 10) at around the same age were 8 men and 2 women, age range: 51–64 years, mean: 58 years.
b
Based on the Manual for the Wechsler Memory Scale-Revised (WMS-R, Japanese edition), n = 50, age range: 55–64 years.