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Valentina Ignatova

Clinic of neurology at MHAT “National Cardiology Hospital” , Bulgaria

Title: Application of evoked potentials in classification and management of headache

Abstract

Headache is a common condition in the clinical practice, but often its correct and timely classification is a challenge for the neurologist. We still cannot rely on objective methods for proper headache differentiation, and practically the diagnosis is based on clinical interviews, patient diaries and physical examination. The mechanisms of headache involve pathophysiological abnormalities, so usually no objective findings from classical tests are found. That is why the application of neurophysiological studies such as evoked potentials (EPs) can serve as a biomarker for early typification of headache, monitoring its course and tracking the effect of applied drug and non-drug therapy. 

The present work traces the relationships between the primary headache groups and evoked potential findings. 

Hypersensitivity in the somatosensory and visual cortex in patients with migraine can be assessed by applying somatosensory evoked potentials (SSEP) and visual evoked potentials (VEP). Brainstem dysfunction can be confirmed by brainstem auditory evoked potentials (BAEP) testing. Specific patterns have been proposed to aid in the identification of migraine headache in both the paroxysmal and non-paroxysmal periods. High frequency oscillations (HFOs), superimposed on SSEP, elicited by stimulation of median nerve, could be used as markers for thalamo-cortical activation. The lack of habituation of evoked responses in patients with migraine is also discussed. In tension type headache higher amplitudes of EPs are found during stimulation of pericranial sites. The role of laser-evoked potentials (LEPs) in assessment of headache considering the cortical responses to nociceptive afferents is also presented. 

EPs are a useful, innocuous and extremely helpful test in the diagnosis and follow-up of headache patients given the complexity of differentiation in chronic headache, when the pain characteristics become less specific and the differential diagnosis becomes wider. The dynamics of their changes can also serve to monitor the effect of the ongoing therapy. 

Key words: headache classification, early diagnosis, evoked potentials, follow up

Biography

Valentina Ignatova is a neurologist with 22 years experience. She has a PhD since 2014. Her scientific interests are focused on multiple sclerosis, Parkinson disease, epilepsy, neurophysiology, neuropsychology. She actively participates in many international conferences and has over 35 scientific publications.