Introduction: Reports of a link between deep brain stimulation (DBS) and autonomic function exist in the literature1. Questionnaires have shown a subgroup of patients with subthalamic (STN) stimulation had increased dyspnoea3 post operatively, compared to control DBS patients4. It has been shown that subthalamic(STN) stimulation for Parkinson’s disease changes ventilatory function, namely improving PEFR, but not volumetric measures of lung function2. This was not explained by improvement in skeletal muscle function alone. The question arises as to whether the dyspnoea reported is a subjective or objective phenomenon.
Methods: We conducted measurements of electrocardiography, spirometry, oscillometry and capnography of patients with DBS of various nuclei, at different stimulator settings, to further investigate this. Stimulation was either at normal frequency (approximately 150Hz), low (30Hz) or off. Of the patients recruited, there were a range of nuclei being stimulated, including the STN and Gpi for movement disorder and anterior cingulate for chronic pain. Questionnaires were also conducted, including the St George’s Respiratory Questionniare, Dyspnoea-12 and SF36. Ethics was obtained for this study.
Results: There was an interesting constellation of findings, with the STN being associated with subjective dyspnoea in a subset of patients. There are differences in the spirometric and oscillometric measurements within subjects when at different stimulation frequencies. This is keeping with understanding of the neuronal and systems level effect that it is thought to have, namely that low frequency stimulation is excitatory and high frequency stimulation mimics lesioning and thus is inhibitory.
Conclusions: Neuromodulation at different central targets has differing effects on the sensation of breathlessness and the objective parameters of breathing.
Patient Care: Understanding the effects that neuromodulation have on the autonomic system gives greater depth of appreciation for central neural control of objective parameters of breathing, and its perception. Respiratory disease is a major cause of worldwide morbidity and this research opens up avenues for future therapeutic interventions to be developed.
Learning Objectives: Neuromodulation at different central targets has differing effects on the sensation of breathlessness and the objective parameters of breathing.
References: 1 Hyam JA, Kringelbach ML, Silburn PA, et al. The autonomic effects of deep brain stimulation--a therapeutic opportunity. Nat Rev Neurol 2012; 8:391-400
2 Hyam JA, Brittain JS, Paterson DJ, et al. Controlling the lungs via the brain: a novel neurosurgical method to improve lung function in humans. Neurosurgery 2012; 70:469-477; discussion 477-468
3 Herigstad M, Hayen A, Wiech K, et al. Dyspnoea and the brain. Respir Med 2011; 105:809-817
4 Chalif JI, Sitsapesan HA, Pattinson KT, et al. Dyspnea as a side effect of subthalamic nucleus deep brain stimulation for Parkinson's disease. Respir Physiol Neurobiol 2014; 192:128-133