Researchers from research institute Brainclinics will present new data at the Brain Stimulation conference in Barcelona. Tabitha Iseger will present data that validate the proof-of-concept behind the new Neuro-Cardiac-Guided TMS (Heart-Brain Coupling) approach. This method could potentially become a new way to more reliably identify the right cortical locations for rTMS stimulation in the treatment of depression. Lana Donse will present some first clinical results on rTMS treatment in Obsessive Compulsive Disorder (OCD), association with sleep problems and predictors for treatment response to rTMS.

Neuro-Cardiac Guided TMS (NCG TMS)

Autonomic regulation is disturbed in depressed patients. Depressed patients express a higher heart rate and a lower heart rate variability (HRV), which is more pronounced in patients with severe MDD. HRV is the variability in heart rate due to external cues, as, for example, respiration. This indicates that the heart is connected to the brain network that is implicated in MDD. Indeed, several studies show connectivity between the brain structures involved in this network (DLPFC, sgACC, vagal nerve) and the heart. Moreover, some research indicates that rTMS treatment leads to heart rate decreases, thus a normalization of heart rate after treatment.

This connectivity can thus be used to validate whether the network is correctly targeted with rTMS. Since the heart is involved, correct targeting of, for example, the DLPFC, should lead to heart rate decreases. If it’s not, the DLPFC might not be targeted accurately. In common rTMS practice, the DLPFC is found according to the 5 (or 6) cm rule (5cm anterior from the place where thumb movement is found), or using the BEAM-F3 method. This is adequate on the group level, but individually there might be substantial variation. Ten healthy subjects received  3 X 5sec. trains of 10Hz TMS on 3 different scalp locations on the left (F3, FC3 and C3), and 3 locations right (F4, FC4 and C4), while their ECG was recorded. The ECG was converted into R-R interval data. As expected, on the group level, the largest HR decrease was observed for both F3 and F4. This is where, in theory, the DLPFC is located. However, substantial inter-individual variability was observed. For some subjects, the location that showed the largest HR decrease was FC3 or FC4. This indicates that for those subjects, the DLPFC might be located more towards FC3 or FC4. The DLPFC is the rTMS target for depression, and targeting it more accurately, could improve clinical response rates in depression. Moreover, the stimulation output might be lowered due to the higher specificity, and rTMS treatment will be better tolerable.  This study thus confirms the earlier proposed concept of Neuro-Cardiac Guided TMS (NCG TMS).

Download the poster by Tabitha Iseger here (Neuro-Cardiac Guided TMS, NCG TMS)

Sleep disturbances in OCD: Association with non-response to rTMS

A group of 22 patients received at least 10 sessions of rTMS. Firstly, rTMS treatment was successful in more than half of the patients, with a response rate of 55%. Responders showed a strong reduction in both OCD and depression symptoms. Secondly, responders and non-responders showed differences in symptoms of sleep disorders, with a larger severity in non-responders. More specifically, symptoms of circadian rhythm sleep disorder could accurately discriminate non-responders from responders. These symptoms could therefore indicate differences in underlying mechanisms, and may be used as a predictor of non-response to rTMS in OCD.

Download the poster by Lana Donse here (Sleep, rTMS and OCD)