Abstracts

Rationale: An electronic nose (eNose) is a non-invasive technology based on analysing exhaled volatile compound patterns and exhaled breath condensate. The eNose is trained by analysing exhaled breath of both patients with a certain disease and control subjects without this disease. Ideally this should result in a ‘breath-print’ representative for a certain disease. Over the last decades eNose measurements have demonstrated to be a potential diagnostic tool in diseases like asthma, tuberculosis and lung cancer, but also e.g. colorectal cancer.Several studies have demonstrated that there is release of prototypical inflammatory cytokines as well as danger signals such as High Mobility Group Box-1 (HMGB1) and their related signalling molecules in epileptogenic brain tissue. Potentially, these increased concentrations could be detected in exhaled breath by an eNose to identify epilepsy breath-prints. We will explore whether an eNose can be used in the clinic to diagnose epilepsy or monitor epilepsy treatment. Methods: Equal numbers of epilepsy patients and control subjects are measured to train the eNose for identifying epilepsy breath-prints. To control for the fact that the patient group is very heterogenous and most epilepsy patients use antiepileptic drugs AEDs, additional groups have been added to the protocol, such as epilepsy patients who, as part of a video/EEG epilepsy surgery protocol (temporarily) taper AEDs, and parameters such as time since the last seizure are added to the model.During the measurement subjects are asked to breathe in and out through the eNose for five minutes. A (disposable) mouthpiece connected to the measuring instrument is placed in the subject’s mouth and the subject’s nose is clipped to avoid entry of non-filtered air. Results: The first analysis of breath patterns of a subset of the epilepsy patients and control subjects shows that the eNose can distinguish between these two groups with 75% sensitivity and 85% specificity. Data from the additional patient groups and the additional parameters are now added to control for potential confounders and fine-tune the epilepsy breath-prints.Breathing for five minutes into the eNose is generally well tolerated by the subjects, but about 5% of the subjects complain about discomfort due to the equipment or experiences shortness of breath. Conclusions: The first results are promising, as the eNose can make a distinction between patients with epilepsy and control subjects. However, before the eNose can be used as a reliable diagnostic tool or as a monitor of treatment effect more patients and various patient groups need to be measured. Funding: N.A.