Table 1. Demographic and Clinical Characteristics of 148 ET Cases.
| All ET Cases (N = 148) | ET Cases with MM (N = 115) | ET Cases without MM (N = 33) | |
| Age (years) | 84.3 ± 5.5 | 83.7 ± 5.4a | 86.5 ± 5.2 |
| range 74–102 | |||
| Gender (female) | 88 (59.5) | 69 (60.0) | 19 (57.6) |
| Educational level | |||
| <High school | 7 (4.7) | 5 (4.3) | 2 (6.1) |
| High school diploma | 46 (31.1) | 38 (33.0) | 8 (24.2) |
| Some college | 14 (9.5) | 12 (10.4) | 2 (6.1) |
| Bachelors degree or higher | 81 (54.7) | 60 (52.2) | 21 (63.6) |
| Total tremor score1 | 24.9 ± 7.3 | 24.6 ± 7.1 | 26.1 ± 7.7 |
| Age of tremor onset (years) | 42.4 ± 22.9 | 42.1 ± 22.2 | 43.2 ± 25.4 |
| Tremor duration (years) | 41.8 ± 22.2 | 41.4 ± 21.9 | 43.2 ± 23.8 |
| Arm tremor at rest | 52 (35.1) | 37 (32.2) | 15 (45.5) |
| FMMSE2 | 26.9 ± 2.7 | 27.1 ± 2.7b | 26.2 ± 2.6 |
| Median 27.0 | Median 28.0 | Median 26.0 | |
| Range 11–30 | Range 11–30 | Range 20–30 | |
| (<24 in 11 (7.4%)) | (<24 in 7 (6.1%)) | (<24 in 4 (12.1%)) | |
| mMMSE3 | 49.1 ± 5.9 | 49.5 ± 5.8c | 47.7 ± 6.0 |
| Median 50.0 | Median 50.0 | Median 49.0 | |
| Range 18–57 | Range 18 – 57 | Range 35–56 | |
| mMMSE executive function score4 | 9.1 ± 1.9 | 9.2 ± 1.9d | 8.6 ± 2.0 |
| Median 10.0 | Median 10.0 | Median 9.0 | |
| Range 3–11 | Range 4–11 | Range 3–11 | |
| MM total score5 | 9.7 ± 9.6 | 12.5 ± 9.1 | 0 ± 0.0 |
| Median 8.0 | Median 10.0 | Median 0.0 | |
| Range 0–50 | Range 3–50 | Range 0–0 | |
Abbreviations: ET, essential tremor; FMMSE, Folstein Mini-Mental State Exam; MM, mirror movements; mMMSE, Modified Mini-Mental Status Examination
Values are either means ± standard deviation or number (percentage).
a
p = 0.01 (Student t test) compared to ET cases without MM.
b
p = 0.03 (Mann–Whitney test) compared to ET cases without MM.
c
p = 0.09 (Mann–Whitney test) compared to ET cases without MM.
d
p = 0.10 (Mann–Whitney test) compared to ET cases without MM.
1
Potential range 0–46.
2
Folstein Mini-Mental State Exam (potential range 0–30 (no impairment)).
3
Modified Mini-Mental Status Examination (potential range 0–57 (no impairment)).
4
Potential range 0–11 (no impairment).
5
Potential range 0–80 (maximum).