Primary orthostatic tremor: is deep brain stimulation better than spinal cord stimulation?

Primary orthostatic tremor (POT) is a rare movement disorder characterised by a tremor of 13–18 Hz in the legs with female preponderance. POT typically causes severe unsteadiness on standing which, when severe, may persist during walking. This can greatly impact day-to-day functions, including activities that require prolonged standing, such as showering. The response to medications is often limited. There are few data on medications for POT. Clonazepam and gabapentin are probably the two most efficacious medications to treat POT, whereas other medications such as levodopa may also have a role.1 On the other hand, case studies have shown favourable outcomes in patients treated with ventralis intermedius medialis (VIM) thalamic nucleus deep brain stimulation (DBS). Blahak et al also reported that four patients responded well to chronic spinal cord stimulation (SCS), at the cost of stimulation-induced paraesthesias.2 Here, we report the surgical treatment response and electrophysiology findings of two additional patients with severe POT. ### Case 1 The patient is a 74-year-old woman who developed progressive unsteadiness and tremor in the legs when standing at age 50. The symptoms improved when she leant on something to support and disappeared when she walked. There was also low-amplitude, high-frequency tremor of the outstretched hands. Surface electromyography (sEMG) showed a short duration (<50 ms), ~16 Hz sEMG bursting in all the recording …