Long-Term Efficacy of Constant Current Deep Brain Stimulation in Essential Tremor.
OBJECTIVE
Ventralis intermedius deep brain stimulation is an established intervention for medication-refractory essential tremor. Newer constant current stimulation technology offers theoretical advantage over the traditional constant voltage systems in terms of delivering a more biologically stable therapy. There are no previous reports on the outcomes of constant current deep brain stimulation in the treatment of essential tremor. This study aimed to evaluate the long-term efficacy of ventralis intermedius constant current deep brain stimulation in patients diagnosed with essential tremor.


METHODS
Essential tremor patients implanted with constant current deep brain stimulation for a minimum of three years were evaluated. Clinical outcomes were assessed using the Fahn-Tolosa-Marin tremor rating scale at baseline and postoperatively at the time of evaluation. The quality of life in the patients was assessed using the Quality of Life in Essential Tremor questionnaire.


RESULTS
Ten patients were evaluated with a median age at evaluation of 74 years (range 66-79) and a mean follow up time of 49.7 (range 36-78) months since starting stimulation. Constant current ventralis intermedius deep brain stimulation was well tolerated and effective in all patients with a mean score improvement from 50.7 ± 5.9 to 17.4 ± 5.7 (p = 0.0020) in the total Fahn-Tolosa-Marin rating scale score (65.6%). Furthermore, the total combined mean Quality of Life in Essential Tremor score was improved from 56.2 ± 4.9 to 16.8 ± 3.5 (p value = 0.0059) (70.1%).


CONCLUSIONS
This report shows that long-term constant current ventralis intermedius deep brain stimulation is a safe and effective intervention for essential tremor patients.
Department of Neurosurgery, Kings College Hospital, London, UK.|Warwick Medical School, The University of Warwick, Coventry, UK.
Ali
http://orcid.org/0000-0002-3262-6118
A
Rezaei Haddad
Department of Neurology, National Parkinson Foundation International Centre of Excellence, King's College Hospital, King's Health Partners, London, UK.
Michael
M
Samuel
Department of Neurosurgery, Kings College Hospital, London, UK.
Natasha
N
Hulse
Department of Neurosurgery, Kings College Hospital, London, UK.|Department of Neurosurgery, Wan Fang Medical Center, Taipei Medical University, Taipei, Taiwan.
Hsin-Ying
HY
Lin
Department of Neurosurgery, Kings College Hospital, London, UK.
Keyoumars
K
Ashkan
D000368:Aged; D046690:Deep Brain Stimulation / Q000379:methods* / Q000639:trends*; D020329:Essential Tremor / Q000175:diagnosis* / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D011182:Postoperative Care / Q000379:methods* / Q000639:trends*; D011795:Surveys and Questionnaires; D013997:Time Factors; D016896:Treatment Outcome
Constant current stimulation; essential tremor