Table 2.
Participants’ demographics, single-nucleotide polymorphisms, neuropsychological tests, and baseline neurophysiological measures.
| All (N = 21) | Group 1 (n = 12) | Group 2 (n = 9) | p | |
|---|---|---|---|---|
| Age (yr, mean ± SD) | 36.9 ± 15.2 | 36.8 ± 15.8 | 37.0 ± 15.3 | 0.98 |
| Sex (M : F) | 19 : 2 | 10 : 2 | 9 : 0 | 0.49 |
| Race (White : non-White) | 10 : 11 | 5 : 7 | 5 : 4 | 0.67 |
| Ethnicity (Hispanic : non-Hispanic) | 5 : 16 | 3 : 9 | 2 : 7 | 1.00 |
| Education (yr, mean ± SD)* | 16.8 ± 2.5 | 16.0 ± 2.4 | 18.1 ± 2.2 | – |
| BDNF (Met− : Met+)† | 12 : 6 | 4 : 5 | 8 : 1 | – |
| APOE (ε4− : ε4+)† | 10 : 8 | 5 : 4 | 5 : 4 | – |
| Handedness (Right : Left) | 21 : 0 | 12 : 0 | 9 : 0 | 1.00 |
| MMSE score (mean ± SD) | 29.9 ± 0.5 | 29.8 ± 0.6 | 29.9 ± 0.3 | 0.80 |
| Abbreviated Stanford-Binet IQ (mean ± SD) | 108.1 ± 12.4 | 104.5 ± 13.4 | 113.0 ± 9.7 | 0.12 |
| Verbal KN score (mean ± SD) | 11.7 ± 2.9 | 10.8 ± 2.6 | 12.9 ± 3.1 | 0.10 |
| Nonverbal FR score (mean ± SD) | 11.0 ± 2.2 | 10.8 ± 2.6 | 11.4 ± 1.4 | 0.47 |
| RMT (% MSO, mean ± SD) | 36.1 ± 7.7 | 36.8 ± 6.6 | 35.1 ± 9.4 | 0.63 |
| AMT (% MSO, mean ± SD) | 26.1 ± 5.2 | 25.8 ± 5.0 | 26.4 ± 5.8 | 0.80 |
| Baseline MEP amplitude (mV, mean ± SD) | 1.4 ± 1.2 | 1.2 ± 1.0 | 1.6 ± 1.3 | 0.50 |
AMT, active motor threshold; APOE, apolipoprotein E; APOE ε4+, ε2/ε4 or ε3/ε4 genotype; APOE ε4−, ε2/ε3 or ε3/ε3; BDNF, brain-derived neurotrophic factor; BDNF Met−, Val66Val; BDNF Met+, Val66Met; FR, fluid reasoning; IQ, intelligence quotient; KN, knowledge; MEP, motor evoked potential; MMSE, Mini-Mental State Examination; MSO, maximum stimulator output; RMT, resting motor threshold; SD, standard deviation. Racial and ethnic categories were defined based on the National Institutes of Health policy and guidelines on the inclusion of women and minorities as subjects in clinical research (NIH Office of Extramural Research, 2001). Groups 1 and 2 were identified by complete-linkage cluster analysis of natural log-transformed, baseline-corrected MEP amplitudes at 5 to 50 minutes post-cTBS. Comparisons of proportions were conducted with Fisher’s exact test. p values were not adjusted for multiple comparisons. Education and single-nucleotide polymorphisms were not statistically compared between the two groups because the data were not available for the total sample.
Education data were available for 12 participants in Group 1 and eight participants in Group 2.
BDNF and APOE results were available for 18 participants.