Sustained reduction of hypertension by deep brain stimulation

Deep brain stimulators were implanted in the left periaqueductal gray matter (PAG) and sensory thalamus for right sided neuropathic facial pain refractory to other treatments in a man aged 58 years. PAG stimulation 8 months later acutely reduced systolic blood pressure by 25 mm Hg during revision surgery. One year post procedure, ambulatory blood pressure monitoring demonstrated significant and sustained reduction in blood pressure with PAG stimulation. Mean systolic blood pressure decreased by 12.6 mm Hg and diastolic by 11.0 mm Hg, alongside reductions in variability of heart rate and pulse pressure. This neurosurgical treatment may prove beneficial for medically refractory hypertension

Regional cerebral perfusion differences between periventricular grey, thalamic and dual target deep brain stimulation for chronic neuropathic pain

Regional cerebral blood flow changes were evaluated in different subcortical brain targets following deep brain stimulation (DBS) for chronic pain. Three patients with intractable neuropathic pain were assessed; one had stimulating electrodes in the ventroposterolateral thalamic nucleus (VPL), one in the periventricular grey (PVG) area, and one had electrodes in both targets. Pain relief was achieved in all patients. Cerebral perfusion was measured by single-photon emission computed tomography to determine the effects of DBS. Comparison was made between individual scans using subtraction analysis. DBS consistently increased perfusion in the posterior subcortical region between VPL and PVG, regardless of the site of stimulation. Furthermore, thalamic and dual target DBS increased thalamic perfusion, yet PVG DBS decreased perfusion in the PVG-containing midbrain region and thalamus. Dual target stimulation decreased anterior cingulate and insular cortex perfusion. The study demonstrates regional differences in cerebral perfusion between three accepted and efficacious targets for analgesic DBS

Ventral periaqueductal grey stimulation alters heart rate variability in humans with chronic pain

Background:the midbrain periaqueductal grey (PAG) area is important for both pain modulation and cardiovascular control via the autonomic nervous system (ANS). While changes in blood pressure dependent upon dorsal or ventral electrode positioning have been described with PAG deep brain stimulation (DBS), little is known mechanistically about the relationships between pain and cardiovascular regulation in humans. Heart rate variability (HRV) is an established measure of cardiovascular regulation, and an index of autonomic function.Methods and results:16 patients undergoing DBS of the rostral PAG for chronic neuropathic pain were investigated post-operatively to determine whether PAG stimulation would alter HRV, and the subjects' perception of pain. Mean heart rate together with HRV, time and frequency domain measures, low frequency (LF) and high frequency (HF) power components of heart rate and the ratio of LF to HF were calculated before and during DBS. Ventral but not dorsal PAG DBS significantly decreased the ratio of LF to HF power (p &lt; 0.05, n = 8) with HF power significantly increased. Changes in LF/HF ratio correlated significantly with subjective reporting of analgesic efficacy using a visual analogue score (VAS; ?2 = 0.36, p = 0.01, n = 16). Diffusion tensor imaging and probabilistic tractography of 17 normal controls' seeding voxels from the mean ventral and dorsal PAG stimulation sites of the 16 patient cohort revealed significant differences between rostral tract projections and separate, adjacent projections to ipsilateral dorsolateral medulla.Conclusions:ventral PAG DBS may increase parasympathetic activity to reduce pain via anatomical connections distinct from dorsal PAG DBS, which may act by sympathetic mechanisms.<br/