| Test | Myoclonus | Chorea | Dystonia | Tremor |
| Typical EMG duration | 25 to 200 ms | 100 to 300 ms | Long: 200 ms to constant | 75 to 150 ms for common tremors |
| Surface EMG pattern | Pulsatile "square wave" with co-contraction between muscles | Constantly changing appearance | Co-contraction between muscles | Sinusoidal oscillatory discharges |
| EEG | May be abnormal in cortical myoclonus | Normal | Normal | Normal |
| Somatosensory evoked potentials | May be abnormal in cortical myoclonus | Normal | Normal | Normal |
| Long latency EMG reflex response | May be abnormal in cortical myoclonus | Usually normal | Usually normal | Usually normal |
