Table 1.
Descriptive statistics for demographic and behavioral measures and ERP responses
| TS group mean (SD) | CAS group mean (SD) | |
|---|---|---|
| Age | 12 y 2 mo (23 mo) | 12 y 7 mo (28 mo) |
| EVT-2 Standard Score | 110.3 (8.5) | 95.5 (18.3) |
| GFTA-2 Standard Score | 101.7 (2.2) | 57.9 (15.6) |
| Number of usable ERP trials (stimulus-locked analysis): | ||
| Simple | 33.1 (13.0) | 30.3 (10.0) |
| Complex | 31.9 (13.6) | 30.4 (12.4) |
| Number of usable ERP trials (stimulus-locked analysis): | ||
| Simple | 43.2 (8.7) | 28.7 (11.8) |
| Complex | 40.8 (7.0) | 31.0 (12.5) |
| Response time (ms) | ||
| Simple | 675.6 (102.2) | 818.7 (80.6) |
| Complex | 679.9 (92.8) | 839.1 (75.6) |
Notes: TS: Typical speech. CAS: Childhood apraxia of speech. ERP: Event-related potentials. EVT-2: Expressive Vocabulary Test-2 (Williams, 2007). GFTA-2: Goldman-Fristoe Test of Articulation-2 (Goldman & Fristoe, 2000). Not that, in a pilot study of 15 typically speaking adults ages 18–35, the average response time was 608 ms (SD 58) for simple items and 617 ms (SD 55) for complex items, suggesting that the TS group of children was approximately 65 ms (or 10%) slower than typically speaking adults.