Table 3.
Percentages of error types arising from stimulation to each brain region
| Error code | IFG | STG/MTG | Other | No stimulation | p (F ≠ T) | p (F ≠ N) |
|---|---|---|---|---|---|---|
| Syntactic error (%) | 10 | 2 | 0 | 0 | 0.0022* | 0.0006* |
| Semantic paraphasia (%) | 2 | 0 | 2 | 0 | N/A | N/A |
| Phonemic paraphasia (%) | 1 | 2 | 2 | 1 | N/A | N/A |
| Perserveration (%) | 7 | 2 | 2 | 2 | 0.040* | 0.17 |
| Pause (%) | 21 | 21 | 12 | 16 | 0.89 | 0.35 |
| Retracing (%) | 16 | 7 | 9 | 6 | 0.030* | 0.024* |
| False start (%) | 7 | 5 | 5 | 5 | 0.50 | 0.61 |
| Abandoned utterance (%) | 1 | 2 | 0 | 0 | N/A | N/A |
| Speech arrest (%) | 10 | 4 | 8 | 0 | 0.064 | 0.0006* |
| Total number of trials | 233 | 121 | 65 | 85 |
IFG = inferior frontal gyrus; STG/MTG = superior temporal gyrus/middle temporal gyrus. Error frequencies were compared between trials with frontal (F) and temporal (T) stimulation, and between frontal (F) and no (N) stimulation, for error types that occurred at least 10 times, using a series of Fisher’s exact tests (2-tailed).
*
= Significant after correction for multiple comparisons using positive false discovery rate (Storey, 2002) as implemented in the MATLAB function mafdr.