Figure 1
Diagnostic Stratification of the LOTS Cohort.
(A) Etiological classification of orthostatic tremor (OT) cases, showing the distribution of primary OT and secondary OT (B) Frequency-based classification of OT using a 13 Hz cutoff, showing the distribution of high-frequency (≥13 Hz) and low-frequency (<13 Hz) OT.
Table 1
Demographic Characteristics of the LOTS Cohort Stratified by Diagnostic Domains.
| BASED ON OT/OM STRATIFICATION | BASED ON PRIMARY OT/SECONDARY OT STRATIFICATION | BASED ON FREQUENCY STRATIFICATION | |||||||
|---|---|---|---|---|---|---|---|---|---|
| VARIABLE | OM | OT | P-VALUE | SOT | POT | P-VALUE | HF | LF | P-VALUE |
| Age | 72.3 ± 8.2 | 69.7 ± 9.2 | 0.481 | 70.9 ± 8.3 | 67.9 ± 10.6 | 0.295 | 66.3 ± 10.1 | 73.8 ± 5.5 | 0.002 |
| Height | 157.8 ± 11.0 | 154.7 ± 7.4 | 0.529 | 155.4 ± 8.8 | 154.4 ± 5.2 | 0.593 | 154.3 ± 8.2 | 155.9 ± 5.8 | 0.441 |
| Weight | 75.4 ± 10.6 | 70.7 ± 9.0 | 0.343 | 71.2 ± 10.4 | 71.4 ± 6.2 | 0.926 | 72.0 ± 9.1 | 71.3 ± 7.4 | 0.778 |
| BMI | 30.3 ± 2.9 | 29.6 ± 3.8 | 0.635 | 29.5 ± 4.1 | 30.0 ± 2.8 | 0.611 | 30.3 ± 3.9 | 29.3 ± 2.4 | 0.284 |
| Females | 3 (50%) | 29 (56%) | 1.000 | 20 (51%) | 12 (63%) | 0.567 | 19 (66%) | 10 (56%) | 0.264 |
| Males | 3 (50%) | 23 (44%) | 19 (49%) | 7 (37%) | 10 (34%) | 8 (44%) | |||
| Marital Status | 6 (100%) | 52 (100%) | – | 39 (100%) | 19 (100%) | – | 29 (100%) | 18 (100%) | – |
| Mixed-Vegetarian Diet | 4 (67%) | 46 (88%) | 0.400 | 31 (79%) | 19 (100%) | 0.085 | 25 (86%) | 16 (89%) | 1.000 |
| Non-vegetarian Diet | 2 (33%) | 6 (12%) | 8 (21%) | 0 (0) | 4 (14%) | 2 (11%) | |||
| Positive Family History | 1 (17%) | 2 (4%) | 0.712 | 3 (8%) | 0 (0%) | 0.542 | 0 (0%) | 2 (11%) | 0.275 |
Table 2
Phenomenological Features Stratified by Diagnostic Domains.
| PHENOMENOLOGICAL FEATURE | BASED ON OT/OM STRATIFICATION | BASED ON PRIMARY OT/SECONDARY OT STRATIFICATION | BASED ON FREQUENCY STRATIFICATION | ||||||
|---|---|---|---|---|---|---|---|---|---|
| OM | OT | P-VALUE | SOT | POT | P-VALUE | HF | LF | P-VALUE | |
| Twitching | 4 (67%) | 36 (69%) | 1.000 | 29 (74%) | 11 (58%) | 0.332 | 20 (69%) | 13 (72%) | 1.000 |
| Bent Knees | 3 (50%) | 26 (50%) | 1.000 | 19 (49%) | 10 (53%) | 1.000 | 13 (45%) | 11 (61%) | 0.432 |
| Toe Clawing | 3 (50%) | 33 (63%) | 0.842 | 26 (67%) | 10 (53%) | 0.456 | 17 (59%) | 11 (61%) | 1.000 |
| Broad base support | 5 (83%) | 22 (42%) | 0.140 | 18 (46%) | 9 (47%) | 1.000 | 13 (45%) | 7 (39%) | 0.923 |
| Tandem Walk | 1 (17%) | 29 (56%) | 0.167 | 21 (54%) | 9 (47%) | 0.854 | 17 (59%) | 9 (50%) | 0.782 |
| Gait | 4 (67%) | 27 (52%) | 0.800 | 27 (69%) | 4 (21%) | 0.002 | 14 (48%) | 10 (56%) | 0.853 |
| Leg Tremulousness | 1 (17%) | 24 (46%) | 0.344 | 18 (46%) | 7 (37%) | 0.697 | 13 (45%) | 10 (56%) | 0.678 |
| Disequilibrium | 4 (67%) | 19 (37%) | 0.323 | 16 (41%) | 7 (37%) | 0.984 | 11 (38%) | 5 (28%) | 0.691 |
| Falls | 1 (17%) | 8 (15%) | 1.000 | 6 (15%) | 3 (16%) | 1.000 | 6 (21%) | 2 (11%) | 0.653 |
| Numbness of Feet | 0 (0%) | 5 (10%) | 0.979 | 3 (8%) | 2 (11%) | 1.000 | 4 (14%) | 1 (6%) | 0.686 |
| Unable to stand static | 1 (17%) | 8 (15%) | 1.000 | 3 (8%) | 6 (32%) | 0.049 | 6 (21%) | 0 (0%) | 0.106 |
| Pain in legs | 0 (0%) | 11 (21%) | 0.483 | 7 (18%) | 4 (21%) | 1.000 | 5 (17%) | 5 (28%) | 0.623 |
| Disappears on leaning | 2 (33%) | 14 (27%) | 1.000 | 14 (36%) | 2 (11%) | 0.086 | 7 (24%) | 6 (33%) | 0.727 |
| Use of Assistive devices | 1 (17%) | 8 (15%) | 1.000 | 7 (18%) | 2 (11%) | 0.729 | 5 (17%) | 2 (11%) | 0.879 |
Table 3
Distribution of Comorbidities Across Diagnostic Domains.
| VARIABLE | BASED ON OT/OM STRATIFICATION | BASED ON PRIMARY OT/SECONDARY OT STRATIFICATION | BASED ON FREQUENCY STRATIFICATION | ||||||
|---|---|---|---|---|---|---|---|---|---|
| OM(%) | OT(%) | P-VALUE | SOT(%) | POT(%) | P-VALUE | HF(%) | LF(%) | P-VALUE | |
| Diabetes | 66.7% | 34.6% | 0.277 | 48.7% | 15.8% | 0.033 | 34.5% | 38.9% | 1.000 |
| Hypertension | 66.7% | 38.5% | 0.373 | 51.3% | 21.1% | 0.056 | 41.4% | 33.3% | 0.808 |
| CKD | 0.0% | 5.8% | 1.000 | 2.6% | 10.5% | 0.513 | 3.4% | 11.1% | 0.667 |
| Hypothyroidism | 0.0% | 7.7% | 1.000 | 10.3% | 0.0% | 0.371 | 10.3% | 5.6% | 0.973 |
| COPD | 0.0% | 1.9% | 1.000 | 2.6% | 0.0% | 1.000 | 0.0% | 5.6% | 0.808 |
| Bipolar disorder | 0.0% | 3.8% | 1.000 | 5.1% | 0.0% | 0.812 | 3.4% | 5.6% | 1.000 |
| Breast Cancer | 0.0% | 1.9% | 1.000 | 2.6% | 0.0% | 1.000 | 0.0% | 5.6% | 0.808 |
| Arrythmia | 0.0% | 3.8% | 1.000 | 5.1% | 0.0% | 0.812 | 0.0% | 5.6% | 0.808 |
| IHD | 0.0% | 5.8% | 1.000 | 7.7% | 0.0% | 0.542 | 10.3% | 0.0% | 0.426 |
| Depression | 0.0% | 3.8% | 1.000 | 5.1% | 0.0% | 0.812 | 3.4% | 5.6% | 1.000 |
| BPH | 0.0% | 3.8% | 1.000 | 5.1% | 0.0% | 0.812 | 3.4% | 5.6% | 1.000 |
| AVN | 0.0% | 0.0% | – | 0.0% | 0.0% | – | 0.0% | 0.0% | – |
| Vertigo | 16.7% | 3.8% | 0.712 | 5.1% | 5.3% | 1.000 | 6.9% | 0.0% | 0.693 |
| PIVD | 0.0% | 11.5% | 0.864 | 15.4% | 0.0% | 0.178 | 10.3% | 16.7% | 0.856 |
| ET | 0.0% | 9.6% | 0.979 | 12.8% | 0.0% | 0.257 | 3.4% | 22.2% | 0.123 |
| OA | 0.0% | 11.5% | 0.864 | 15.4% | 0.0% | 0.178 | 13.8% | 11.1% | 1.000 |
| Polyneuropathy | 50.0% | 19.2% | 0.232 | 33.3% | 0.0% | 0.012 | 27.6% | 11.1% | 0.330 |
| Cervical myelopathy | 0.0% | 0.0% | – | 0.0% | 0.0% | – | 0.0% | 0.0% | – |
| Dementia | 16.7% | 15.4% | 1.000 | 23.1% | 0.0% | 0.059 | 10.3% | 16.7% | 0.856 |
| Medication induced Myoclonus | 0.0% | 1.9% | 1.000 | 2.6% | 0.0% | 1.000 | 3.4% | 0.0% | 1.000 |
| Auto-immune encephalitis | 0.0% | 1.9% | 1.000 | 2.6% | 0.0% | 1.000 | 3.4% | 0.0% | 1.000 |
| IPD | 0.0% | 5.8% | 1.000 | 7.7% | 0.0% | 0.542 | 0.0% | 11.1% | 0.275 |
| PSP | 0.0% | 1.9% | 1.000 | 2.6% | 0.0% | 1.000 | 0.0% | 0.0% | – |
| DLBD | 0.0% | 1.9% | 1.000 | 2.6% | 0.0% | 1.000 | 0.0% | 0.0% | – |
| MSA-P | 0.0% | 1.9% | 1.000 | 2.6% | 0.0% | 1.000 | 0.0% | 0.0% | – |
| Canal stenosis | 0.0% | 3.8% | 1.000 | 5.1% | 0.0% | 0.812 | 3.4% | 5.6% | 1.000 |
| Spondylosis | 0.0% | 1.9% | 1.000 | 2.6% | 0.0% | 1.000 | 0.0% | 5.6% | 0.808 |
[i] All comparisons are presented for descriptive purposes only. Given small subgroup sizes and multiple comparisons, P-values should be interpreted cautiously and are provided solely to indicate the absence of strong discriminatory signals rather than to support confirmatory inference.
OT, orthostatic tremor; OM, orthostatic myoclonus; POT, primary orthostatic tremor; SOT, secondary orthostatic tremor; HF, high-frequency; LF, low-frequency; CKD, chronic kidney disease; COPD, chronic obstructive pulmonary disease; IHD, ischemic heart disease; BPH, benign prostatic hyperplasia; AVN, avascular necrosis; ET, essential tremor; OA, osteoarthritis; PIVD, prolapsed intervertebral disc; IPD, idiopathic Parkinson’s disease; PSP, progressive supranuclear palsy; DLBD, dementia with Lewy bodies; MSA-P, multiple system atrophy–parkinsonian type.
Table 4
Functional Outcomes Stratified by Diagnostic Domains.
| OUTCOME | BASED ON OT/ OM STRATIFICATION | BASED ON PRIMARY OT/ SECONDARY OT STRATIFICATION | BASED ON FREQUENCY STRATIFICATION | ||||||
|---|---|---|---|---|---|---|---|---|---|
| OM (MEAN ± SD) | OT (MEAN ± SD) | ANOVA P-VALUE | SOT (MEAN ± SD) | POT (MEAN ± SD) | ANOVA P-VALUE | HF (MEAN ± SD) | LF (MEAN ± SD) | ANOVA P-VALUE | |
| OT-10 | 26.17 ± 7.68 | 26.90 ± 11.40 | 0.878 | 28.46 ± 10.54 | 23.47 ± 11.50 | 0.106 | 27.21 ± 12.05 | 24.17 ± 10.89 | 0.388 |
| OTIP | 71.17 ± 28.84 | 71.87 ± 34.53 | 0.962 | 75.38 ± 33.57 | 64.42 ± 33.84 | 0.249 | 75.45 ± 40.24 | 65.00 ± 26.12 | 0.333 |
| SF36 (1) | 42.50 ± 27.16 | 35.48 ± 19.31 | 0.422 | 33.72 ± 18.70 | 41.32 ± 22.29 | 0.178 | 32.07 ± 20.94 | 40.00 ± 16.54 | 0.180 |
| SF36 (2) | 54.17 ± 45.87 | 46.15 ± 36.84 | 0.624 | 41.03 ± 36.49 | 59.21 ± 37.46 | 0.083 | 41.38 ± 37.37 | 51.39 ± 37.84 | 0.379 |
| SF36 (3) | 55.56 ± 45.54 | 58.98 ± 36.52 | 0.833 | 52.14 ± 38.08 | 71.93 ± 31.94 | 0.056 | 58.62 ± 37.43 | 61.11 ± 38.35 | 0.827 |
| SF36 (4) | 63.33 ± 11.69 | 56.83 ± 19.07 | 0.419 | 56.54 ± 19.37 | 59.47 ± 16.82 | 0.575 | 54.83 ± 21.48 | 58.89 ± 16.50 | 0.497 |
| SF36 (5) | 80.00 ± 11.87 | 68.69 ± 20.86 | 0.200 | 67.90 ± 21.51 | 73.89 ± 17.56 | 0.296 | 66.90 ± 22.60 | 72.00 ± 20.44 | 0.440 |
| SF36 (6) | 81.25 ± 13.11 | 62.02 ± 25.24 | 0.073 | 60.90 ± 22.79 | 70.39 ± 28.32 | 0.175 | 59.48 ± 29.63 | 65.28 ± 20.81 | 0.472 |
| SF36 (7) | 73.75 ± 20.96 | 75.53 ± 24.44 | 0.865 | 66.22 ± 22.69 | 94.08 ± 13.31 | 0.000 | 78.71 ± 25.18 | 72.22 ± 26.46 | 0.404 |
| SF36 (8) | 75.00 ± 18.71 | 57.21 ± 25.87 | 0.109 | 55.00 ± 26.11 | 67.37 ± 23.24 | 0.085 | 53.28 ± 29.53 | 60.56 ± 21.62 | 0.370 |
Table 5
Treatments Stratified by Diagnostic Domains
| VARIABLE | BASED ON OT/OM STRATIFICATION | BASED ON PRIMARY OT/SECONDARY OT STRATIFICATION | BASED ON FREQUENCY STRATIFICATION | ||||||
|---|---|---|---|---|---|---|---|---|---|
| OM(%) | OT(%) | P-VALUE | SOT(%) | POT(%) | P-VALUE | HF(%) | LF(%) | P-VALUE | |
| Clonazepam | 100.0% | 78.8% | 0.483 | 76.9% | 89.5% | 0.431 | 82.8% | 77.8% | 0.968 |
| Levetiracetam | 33.3% | 5.8% | 0.131 | 12.8% | 0.0% | 0.257 | 0.0% | 16.7% | 0.097 |
| Gabapentin | 0.0% | 17.3% | 0.608 | 15.4% | 15.8% | 1.000 | 17.2% | 22.2% | 0.968 |
| Beta blocker | 33.3% | 57.7% | 0.482 | 59.0% | 47.4% | 0.580 | 62.1% | 44.4% | 0.379 |