Table 1:
Baseline demographics, and summary of baseline clinical and volumetric data as a function of CAP group.
| CAP Category | IMAGE | TRACK | PREDICT | Combined data | |
|---|---|---|---|---|---|
| N | 1 | 36 | 155 | 139 | 330 |
| 2 | 5 | 13 | 143 | 161 | |
| 3 | 21 | 69 | 143 | 233 | |
| 4 | 46 | 188 | 124 | 358 | |
| Female (% within category) | 1 | 24 (67%) | 69 (44%) | 86 (62%) | 179 (54%) |
| 2 | 3 (60%) | 4 (31%) | 105 (73%) | 112 (69%) | |
| 3 | 9 (43%) | 32 (46%) | 102 (71%) | 143 (61%) | |
| 4 | 24 (52%) | 85 (45%) | 68 (55%) | 177 (49%) | |
| Age (years) | 1 | 42.67 (13.93) | 45.7 (10.29) | 44.81 (11.79) | 44.39 (12.00) |
| 2 | 38.05 (10.13) | 36.34 (9.96) | 33.19 (8.67) | 35.86 (9.58) | |
| 3 | 41.41 (10.19) | 41.12 (9.08) | 40.95 (10.02) | 41.16 (9.76) | |
| 4 | 50.25 (9.80) | 46.29 (10.16) | 45.24 (10.80) | 47.26 (10.25) | |
| Education (standardized levels) | 1 | 5.18 (0.43) a | 3.98 (1.28) | 4.35 (0.89) | 4.27 (1.13) |
| 2 | 5.58 (0.27) a | 4 (1.03) | 4.3 (0.89) | 4.31 (0.92) | |
| 3 | 5.02 (0.53) a | 4.07 (1.05) | 4.26 (0.87) | 4.27 (0.94) | |
| 4 | 5.04 (0.47) a | 3.68 (1.31) | 4.24 (0.98) | 4.04 (1.21) | |
| TMS | 1 | 0.63 (0.51) b | 1.42 (1.65) | 3.56 (4.18) | 2.48 (3.37) |
| 2 | 1.60 (0.86) | 4.38 (4.56) | 4.18 (6.13) | 4.11 (5.97) | |
| 3 | 1.71 (1.44) | 4.06 (4.71) | 8.11 (8.18) | 6.28 (7.36) | |
| 4 | 15.75 (13.42) | 16.42 (14.12) | 14.68 (13.11) | 15.73 (13.71) | |
| TFC | 1 | - | 12.98 (1.47) | 12.92 (0.51) | 12.95 (1.09) |
| 2 | - | 13.00 (0.00) | 12.74 (1.06) | 12.85 (0.25) | |
| 3 | - | 12.78 (1.46) | 12.37 (1.38) | 12.58 (1.23) | |
| 4 | - | 11.58 (1.46) | 12.16 (1.41) | 11.89 (1.36) | |
| SDMT | 1 | 56.28 (9.94) | 52.46 (9.46) | 53.52 (9.78) | 53.32 (9.72) |
| 2 | 56.00 (10.31) | 49.85 (12.12) | 56.68 (10.81) | 56.11 (11.07) | |
| 3 | 50.80 (8.90) | 52.54 (11.04) | 49.74 (10.79) | 50.66 (10.79) | |
| 4 | 38.88 (12.43) | 39.59 (12.84) | 43.04 (10.61) | 40.70 (12.19) | |
| Stroop (word) | 1 | 109.75 (16.34) | 105.27 (16.92) | 103.23 (17.27) | 104.90 (17.11) |
| 2 | 109.00 (8.15) | 97.00 (11.07) | 105.71 (15.46) | 103.43 (15.61) | |
| 3 | 101.20 (18.90) | 102.06 (17.03) | 95.32 (18.67) | 97.83 (18.49) | |
| 4 | 87.68 (23.16) | 85.84 (21.05) | 86.43 (18.42) | 86.28 (20.65) | |
| Putamen | 1 | 0.006 (0.001) | 0.006 (0.001) | 0.006 (0.001) | 0.006 (0.001) |
| 2 | 0.005 (0.001) | 0.006 (0.001) | 0.006 (0.001) | 0.006 (0.001) | |
| 3 | 0.005 (0.001) | 0.005 (0.001) | 0.005 (0.001) | 0.005 (0.001) | |
| 4 | 0.004 (0.001) | 0.004 (0.001) | 0.004 (0.001) | 0.004 (0.001) | |
| Caudate | 1 | 0.004 (0.001) | 0.004 (0.001) | 0.004 (0.001) | 0.004 (0.001) |
| 2 | 0.004 (0.001) | 0.004 (0.001) | 0.004 (0.001) | 0.004 (0.001) | |
| 3 | 0.004 (0.001) | 0.004 (0.001) | 0.004 (0.001) | 0.004 (0.001) | |
| 4 | 0.003 (0.001) | 0.003 (0.001) | 0.003 (0.001) | 0.003 (0.001) | |
| GM | 1 | 0.438 (0.0221) | 0.437 (0.048) | 0.426 (0.042) | 0.433 (0.044) |
| 2 | 0.430 (0.011) | 0.442 (0.051) | 0.445 (0.033) | 0.444 (0.035) | |
| 3 | 0.438 (0.018) | 0.436 (0.046) | 0.432 (0.037) | 0.434 (0.039) | |
| 4 | 0.408 (0.021) | 0.406 (0.043) | 0.411 (0.036) | 0.408 (0.038) | |
| WM | 1 | 0.310 (0.018) | 0.327 (0.035) | 0.320 (0.041) | 0.322 (0.037) |
| 2 | 0.305 (0.007) | 0.320 (0.039) | 0.316 (0.031) | 0.316 (0.031) | |
| 3 | 0.315 (0.015) | 0.325 (0.035) | 0.316 (0.032) | 0.319 (0.032) | |
| 4 | 0.291 (0.019) | 0.302 (0.030) | 0.314 (0.033) | 0.305 (0.031) |
Data represent mean of the number of participants and the standard deviation at baseline. Standard deviation is replaced with percentages for categorical variables. CAP: product of CAG repeat length and age calculated using CAP = Age × (CAG – 33.66); CAP category is 1 = controls, 2 = far from onset, 3 = medium to onset, 4 = close to onset.
UHDRS-TMS: Unified Huntington’s Disease Rating Scale-Total Motor Score; UHDRS-TFC: Unified Huntington’s Disease Rating Scale-Total Functional Capacity; SDMT: Symbol Digit Modality Test. Volumetric data are recorded as a percentage of Intracranial volume (ICV).
For IMAGE-HD cohort, education level was not recorded; this was estimated by re-scaling the National Adult Reading Test (NART) IQ scores that were acquired as part of the study following [23] where the NART score is found to be inter-related with the years of education.
For controls in IMAGE, UHDRS-TMS was not recorded; this was estimated using tapping task data (see Appendix 2 for details). Comparatively low UHDRS-TMS scores observed for CAP 3 in IMAGE is due to low CAG repeats in the IMAGE population compared to that of TRACK and PREDICT.