The heartbeat-evoked brain potential in patients suffering from diabetic neuropathy and in healthy control persons

Objectives: Neurotransmission from the heart to the brain results in a heartbeat evoked potential (HEP). This potential appears as a positive waveform ranging from 250 to 600 ms after the onset of ventricular contraction. Only limited information exists as to what extent the HEP is sensitive to a dysfunction in cardio-afferent pathways. Thus, the HEP was studied in patients with autonomic diabetic neuropathy. Methods: Twenty-five patients and a healthy control group of equal size participated. The HEP was obtained as the average over 1200 EEG sweeps (18 channels) sampled contingent upon the onset of ventricular contraction. A heartbeat attention task and a distraction task were employed. Patients answered a questionnaire pertaining to the frequency of subjective symptoms related to diabetic neuropathy. Results: The HEP amplitude at frontal, central and temporal locations was significantly diminished in patients in the latency range of 280–330 ms. A significant correlation was found between the questionnaire score of subjective autonomic symptoms and the reduction in the HEP. Conclusions: We conclude that the HEP is sensitive to a comparably moderate abnormality in nerve function. Furthermore, we assume that the processing of subjective symptoms of the disease and the generation of the HEP share some common neuronal pathways.