Cyclic deep brain stimulation for obsessive-compulsive disorder

Deep brain stimulation (DBS) targeted at the ventral anterior limb of the
internal capsule (vALIC) is an effective treatment for refractory
obsessive-compulsive disorder (OCD). However, effective DBS for these patients
requires relative high voltages and therefore frequent replacement of the
implanted pulse generator (IPG) or, in case of a rechargeable IPG, frequent and
long charging sessions. In addition, DBS for OCD comes with a small risk for
adverse effects, such as impulsivity, mood swings, tics or other movement
disorders, and potential negative effects on cognitive performance. Advancing
DBS for psychiatric applications requires optimizing energy efficiency and
minimizing adverse event. For the current study, we will test a new method of
cyclic (non-continuous) stimulation that will make the IPG become twice as
power-efficient, while potentially retaining clinical effects, limiting
side-effects and improving cognitive performance.

Our primary objective is to compare the effects of cyclic DBS with continuous
DBS in OCD patients on 1) symptom severity. Secondary, we will compare the
effects on 1) battery life 2) adverse events 3) cognitive performance 4)
cortical EEG oscillations related to cognitive control 5) quality of life.

16 OCD patients currently treated with DBS at the AMC will be included in an
4-week double blind, randomized crossover study. Patients will be randomized to
2 weeks of cyclic DBS followed by 2 weeks of continuous DBS, or vice versa.
Symptoms, adverse events, and battery power in patients with a non-rechargeable
IPG or battery usage between last 6 charging sessions for patients with a
rechargeable IPG will be measured at baseline, after the first crossover block
(T1) and after the second crossover block (T2). Also, cognitive performance,
EEG and quality of life will be measured at T1 and T2.

Continuous DBS, i.e. the patients regular DBS settings
Cyclic DBS, i.e. the regular DBS settings delivered in a cyclic pattern of 0.1
seconds ON and 0.2 seconds OFF.

Participants could have a direct benefit, as the studied intervention might
lead to more energy-efficient DBS with less side-effects. Participants are
already implanted with a DBS system containing the settings for cyclic
stimulation; therefore there is no additional surgical risk. The main risk is a
potential worsening of clinical symptoms during cyclic DBS, in which case we
will offer an admission to our psychiatric department. Additionally, there will
be a burden in time for the three study-visits at our department and two
telephone calls, which will be a total of 6.5 hours in 4 weeks.