Olav is a clinical neuropsychologist and the specialist in the Netherlands in the field of tinnitus and hyperacusis. After his training and research at Erasmus MC (2000–2011), he has treated thousands of patients, both in elderly psychiatry and in neuro-rehabilitation at Rijndam Rehabilitation Centre. He is known as the author of the bestselling book "First Aid for Tinnitus" (EHBO-oorsuizen), in which he clearly explains how tinnitus develops according to the biopsychosocial model and how you can gradually regain control over your symptoms with insights and concrete exercises. It is now in its sixteenth edition and is considered a standard work in that field. Based on his book, he developed the successful e-health module "Control over Tinnitus" (also known as EHBO-oorsuizen), a cognitive-behavioural therapy programme that allows people to gain control over tinnitus independently. This module is offered through platforms such as Therapieland and Gezondeboel. Olav also plays an active role in education and knowledge sharing: he has advised various patient courses such as "Control over Tinnitus", provides guidance as a freelance tinnitus consultant to healthcare professionals, and is co-founder of the Facebook support group 'First Aid for Tinnitus', which now has thousands of members.