Table 1.
Comparison of Demographic Characteristics and Motor Features of ET→PD, ET, and PD Patients
| ET→PD (n = 18) | ET (n = 20) | PD (n = 30) | Significance (p) | |
| Demographic characteristics | ||||
| Age at last visit (mean±SD years) | 74.4±8.2 | 72.8±8.1 | 71.0±7.3 | 0.341 |
| Gender (males: n; %) | 13; 72.2% | 11; 55.0% | 21; 70.0% | 0.453 |
| ET→PD vs. ET | ||||
| Age at onset of ET (mean±SD years) | 49.8±18.6 | 47.6±24.8 | – | 0.752 |
| Duration of ET (mean±SD years) | 24.0±15.6 | 25.4±21.6 | – | 0.822 |
| Duration of ET prior to PD onset (mean±SD years) | 19.3±15.7 | – | – | – |
| Family history of ET (n; %) | 9/17; 52.9% | 11/20; 55.0% | – | 0.903 |
| Family history of PD (n; %) | 3/17; 17.6% | 2/20; 10.0% | – | 0.503 |
| Rest tremor (n; %) | 13/16, 81.2% | 5/19; 26.3% | – | <0.0013 |
| Bradykinesia (n; %) | 11/12, 91.7% | 3/18; 16.7% | – | <0.00013 |
| Rigidity (n; %) | 11/12, 91.7% | 5/19; 26.3% | – | <0.00013 |
| Postural instability (n; %) | 4/16; 25.0% | 1/17; 5.9% | – | 0.133 |
| Cerebellar signs (n; %) | 1/15, 6.7% | 6/18, 33.3% | – | 0.063 |
| Widespread postural and/or action tremor (n; %) | 2/17; 11.8% | 11/17; 64.7% | – | 0.0013 |
| Lower limb tremor (n; %) | 1/17; 5.9% | 4/17; 23.5% | 0.153 | |
| Head tremor (n,%) | 1/17; 5.9% | 7/17; 41.2% | 0.023 | |
| Voice tremor (n, %) | 2/17; 11.8% | 4/17; 23.5% | 0.373 | |
| Need >1 medication for ET at most recent visit (n; %) | 2/17; 11.8% | 12/18; 66.7% | – | 0.0013 |
| ET→PD vs. PD | ||||
| Age at onset of PD (mean±SD years) | 71.4±10.1 | – | 67.7±7.0 | 0.142 |
| Duration of PD (mean±SD years) | 4.8±7.6 | – | 3.8±4.2 | 0.562 |
| Family History of ET (n, %) | 9/17; 52.9% | – | 2/24; 8.3% | <0.00013 |
| Family history of PD (n; %) | 5/17; 29.4% | – | 7/29; 24.1% | 0.803 |
| First symptom of PD | ||||
| Rest tremor (n; %) | 8/15; 53.3% | – | 19/27; 70.4% | 0.183 |
| Bradykinesia (n; %) | 7/15; 46.7% | – | 6/27; 22.2% | |
| Rigidity (n; %) | 0/15; 0% | – | 2/27; 7.4% | |
| UPDRS – rest tremor upper limb (mean±SD)2 | 1.3±1.04 | – | 1.0±1.04 | 0.252 |
| UPDRS – finger tapping (mean±SD)5 | 1.1±0.74 | – | 1.5±0.74 | 0.102 |
| UPDRS – rigidity upper limb (mean±SD)5 | 1.1±0.54 | – | 1.4±0.64 | 0.102 |
| UPDRS – pull test (mean±SD) | 0.5±0.64 | – | 0.2±0.44 | 0.252 |
| UPDRS total (mean±SD) | 22.4±14.84 | – | 30.4±17.64 | 0.142 |
| Hoehn and Yahr score (mean±SD) | 2.2±0.7 | – | 2.0±0.4 | 0.222 |
| Schwab and England score (mean±SD) | 91.8±7.24 | – | 87.9±8.74 | 0.152 |