TABLE 1.
Demographics and pathological features of patients with ET and control cases
| Variables | Controls | ET Cases | P Value |
|---|---|---|---|
| n | 15 | 15 | |
| Age at death (yr) | 83.9 ± 10.0 | 87.5 ± 5.2 | 0.750a |
| Median = 87.0 | Median = 88.0 | ||
| Age of tremor onset (yr) | NA | 38.5 ± 23.9 | |
| Duration of tremor (yr) | NA | 48.7 ± 25.1 | |
| Sex | 0.273b | ||
| Men | 9 (60.0%) | 6 (40.0%) | |
| Women | 6 (40.0%) | 9 (60.0%) | |
| Postmortem intervals (hr) | 14.1 ± 9.1 | 29.9 ± 14.5 | <0.001a |
| Median = 10.96 | Median = 31.4 | ||
| Braak AD stagec | 0.248b | ||
| 0 | 2 (14.3%) | 0 (0.0%) | |
| 1 | 1 (7.1%) | 0 (0.0%) | |
| 2 | 5 (35.7%) | 4 (26.7%) | |
| 3 | 4 (28.6%) | 5 (33.3%) | |
| 4 | 1 (7.1%) | 5 (33.3%) | |
| 5 | 1 (7.1%) | 0 (0.0%) | |
| 6 | 0 (0.0%) | 1 (7.1%) | |
| CERAD scores | 0.736b | ||
| 0 | 7 (46.7%) | 9 (60.0%) | |
| A | 4 (26.7%) | 3 (20.0%) | |
| B | 4 (26.7%) | 2 (13.3%) | |
| C | 0 (0.0%) | 1 (6.7%) | |
| Braak PD stage | 0.0 ± 0.0 | 0.1 ± 0.5d | 1.000e |
| PC counts | 11.9 ± 1.7 | 8.8 ± 1.5 | <0.001e |
| Torpedo counts | 6.9 ± 7.0 | 15.2 ± 12.9 | 0.041e |
| Percentage of CFs extending into PF territory | 17.5 ± 9.0 | 30.0 ± 6.1 | <0.001e |
| Number of PC somas that a single CF crosses (mm−1) | 8.8 ± 1.9 | 10.5 ± 1.9 | 0.023e |
| Number of PC dendrites that a single CF crosses (mm−1) | 10.7 ± 3.5 | 14.9 ± 5.1 | 0.014e |
Values represent mean ± standard deviation or number (percentage), and for variables with a nonnormal distribution, the median is reported as well. Postmortem intervals indicate the time from death to the time of brain placed in −80°C. Mean number of PC counts per 100× microscopic field, among 15 sampled fields in a section, and normalized to the PC layer length. The number of PC axonal torpedoes was quantified throughout each cerebellar section and normalized to the PC layer length.
Abbreviations: ET, essential tremor; NA, not applicable; AD, Alzheimer’s disease; CERAD, consortium to establish a registry for Alzheimer’s disease; PD, Parkinson’s disease; PC, Purkinje cell; CF, climbing fiber; PF, parallel fiber.
Independent samples Mann–Whitney U test.
Fisher’s exact test.
One Braak AD stage value in control group is a missing value.
One ET case has incidental Lewy body with Braak PD stage of 2.
Independent samples t test.