Figure 1
Histogram Analysis Showing the Distribution of Dominant Tremor Frequencies.
Table 1
Neurophysiologic Features
| <10 Hz (n = 8) | 10–13 Hz (n = 6) | >13 Hz (n = 14) | |
|---|---|---|---|
| Phase relationship1 | |||
| Mixed | 3 | 1 | 9 |
| Alternating | 2 | 3 | 2 |
| Co-contraction | 3 | 2 | 3 |
| Mean inter-muscular coherence (95% CI)2 | 0.53 (0.43–0.63) | 0.74 (0.60–0.89) | 0.91 (0.88–0.94) |
| Mean width in Hz of dominant frequency peak at half peak amplitude (95% CI) | 1.51 (1.24–1.79) | 1.00 (0.65–1.35) | 0.66 (0.59–0.72) |
| Arm tremor leaning3 | 3/3 (all <10 Hz) | 1/1 (12.45 Hz) | 8/8 (all 13–19Hz) |
| Arm tremor with postural activation (n, %) | 6 (75) | 2 (33.3) | 9 (64.2) |
| Arm tremor discharges 13–18 Hz | 0 | 0 | 5 |
| Arm tremor discharges 10–13 Hz | 2 | 2 | 0 |
| Arm tremor discharges <10 Hz | 4 | 0 | 4 |
Figure 2
Surface Electromyography Tracings and Spectral Analysis in Patients with High-, Intermediate-, and Low-Frequency Orthostatic Tremor.
Figure 3
Dominant Tremor Frequency vs. Spectral Peak Width at Half Peak Amplitude for Each Patient (blue <10 Hz; green 10–13 Hz; red 13–19 Hz)..
Table 2
Demographic and Clinical Information
| <10 Hz (n = 8) | 10–13 Hz (n = 6) | >13 Hz (n = 14) | p-value | |
|---|---|---|---|---|
| Mean age (years) | 75 | 69.5 | 71.21 | 0.690 |
| Gender female/male (% female) | 7/1 (87.5) | 2/4 (33.3) | 8/6 (57.1) | 0.122 |
| Mean disease duration (years) | 2.00 | 7.96 | 11.43 | 0.002 |
| Mean age at disease onset (years) | 72.88 | 61.3 | 59.71 | 0.093 |
| Symptoms1 | ||||
| Feeling of tremor | 4 (50) | 6 (100) | 13 (92.8) | 0.032 |
| Unsteadiness with standing | 8 (100) | 6 (100) | 14 (100) | |
| Unsteadiness with walking | 6/7 (85.7) | 4 (66.6) | 3 (21.4) | 0.016 |
| Documented falls | 3 (37.5) | 3 (50) | 0 (0.00) | 0.010 |
| Examination | ||||
| Leg tremor | 5 (62.5) | 5 (83.3) | 12 (85.7) | 0.493 |
| Abnormal gait | 5/7 (71.4) | 4 (66) | 2 (14.3) | 0.017 |
| Family history of tremor | 3 (37.5) | 0 (0) | 3 (21.4) | 0.145 |