Table 1
Features Distinguishing Parkinson's Disease from Psychogenic Parkinsonism
| Feature | Parkinson's Disease | Psychogenic Parkinsonism |
|---|---|---|
| Bradykinesia (repetitive movements) | Progressive slowness with amplitude decrement (sequence effect) | Slowness without amplitude decrement |
| Rigidity | Cogwheeling | Paratonia (active resistance) |
| Effect of reinforcement maneuvers | Rigidity increases | Rigidity diminishes |
| Tremor | Rest, postural, and kinetic | Rest, postural, and kinetic |
| Effect of distraction | Increases in amplitude | Decreases in amplitude or disappears |
| Effect of holding weight | Tremor not transmitted | Tremor may be transmitted to other body segments |
| Effect of entrainment | Tremor may entrain to rate and rhythm of repetitive movements | Tremor is frequently entrained to contralateral repetitive movements |
| Finger tremor | Common | Rare |
| Frequency in different body parts1 | Different frequencies | Same frequencies |
| Walking | Slow, stiff, with retropulsion or propulsion | Slow, stiff, may be painful |
| Arm posture while walking | Partially flexed | Extended in adduction, held stiffly at side (this posture may persist while running) |
| Arm swing | Typically decreased | May be decreased |
| Freezing | Common | Absent |
| Pull test | Variable retropulsion, patient may fall | Normal or exaggerated with flailing of the arms during posterior displacements, reeling back, but almost never falling. |
| l-dopa-induced dyskinesias | Dystonia, chorea, athetosis | Hyperkinetic bizarre movements |
Figure 1
Patient Scans.
(A) Dopamine transporter imaging with photon emission tomography (DaT-SPECT) in a patient with psychogenic parkinsonism shows normal dopaminergic innervation of the basal ganglia. (B) DaT-SPECT in a patient with Parkinson's disease shows bilateral decreased presynaptic dopamine transporter in the basal ganglia.
Table 2
Differential Diagnosis of Conditions with Normal Dopamine Transporter Imaging with Photon Emission Tomography
| Psychogenic Parkinsonism |
|---|
| Vascular parkinsonism |
| Drug-induced parkinsonism |
| Dystonic tremor |
| Essential tremor |
| Orthostatic tremor |
| Dopa-responsive dystonia |
| Healthy subjects |
Table 3
Case Series Studies of Children with Psychogenic Movement Disorders
| Reference | No. of Patients | Female–Male | Mean Age or Range of Onset (years) | Most Common PMDs1 |
|---|---|---|---|---|
| Ferrara and Jankovic68 | 54 | 42:12 | 14.2 | Tremor n = 35, dystonia n = 29, myoclonus n = 20, gait disorders n = 12, other n = 12 |
| Ahmed et al.34 | 11 | 4:7 | 6.11–15.11 | Tics n = 6, tremor n = 4, clonus n = 1 |
| Schwingenschuh et al.74 | 15 | 12:3 | 12.3 | Dystonia n = 7, tremor n = 6, gait disorder n = 2 |
| Dale et al.69 | 12 | 10:2 | 12.7 | Tremor n = 10, myoclonus n = 5, dystonia n = 4, tics n = 1 |
| Faust and Soman36 | 14 | 11:3 | 13.1 | Dystonia n = 6, myoclonus n = 3, tremor n = 3, chorea n = 2 |
| Canavese et al.71 | 14 | 8:6 | 11.5 | Tremor n = 5, myoclonus n = 6, dystonia n = 6, gait disorder n = 2 |