Abstract
Introduction: Neurexan®, a medicinal product sold over the counter (OTC), is composed of four plant and mineral ingredients; passionflower, oats, coffee and zinc valerianate. Neurexan® has been investigated in patients with symptoms related to acute stress, nervousness/restlessness, and insomnia. The previous research suggested an attenuated neuroendocrine stress response in healthy volunteers induced by Neurexan® (Doering et al. 2016). This study further explores the effects of Neurexan® on cognitive performance and attention. It is generally recognized that stress is associated with cognitive impairments. Expecting that Neurexan® reduces the stress level, we hypothesized that the subjects in the placebo group would be more susceptible to distraction compared to treatment group.
Material and Methods: In a randomized, placebo-controlled, double-blind, two-period crossover trial, brain responses of 39 healthy, moderate stressed males were measured during an unattended auditory oddball paradigm via 64-channel electroencephalogram (EEG) after intake of Neurexan® and placebo. The paradigm consisted of 80 standard tones and two types of deviant tones (10 frequency deviant; 10 duration deviant), presented in a pseudo-randomized order. The standard tone was composed of eight equally loud sinusoidal tones (fundamental frequency 330 Hz and seven harmonic partials) and had a duration of 100 ms. The deviants were either 40 ms shorter (duration deviant) or 1.25 semitones higher (frequency deviant).
Results: Here we present the results about the effect of Neurexan treatment on both mismatch negativity (MMN) and latency of the peaks when assessing EEG responses (ERPs) to deviant tones (frequency and duration deviant) compared to placebo.
Discussion: Our findings suggest that Neurexan® also leads to subtle primary processing changes additionally to its postulated top down effects.
