The recruitment of NHS patients will follow a similar process to the other volunteers. Recruitment leaflets will be put at the reception and waiting areas of each different department. A copy of the information sheet and the consent sheet can be obtained from the receptionists upon request. Participants who wish to take part in this study will have to contact the lead examiner (Marwah Albahrani) through the contact details on the recruitment flyers and the information sheets. Informed consent will obtained following the procedure explained under the subheading "obtaining informed consent".