Brain Neuronal Networks, Chemosensory and Trigeminal Functions in Allo-HSCT

Participants will undergo various tests: * Smell function assessment with Sniffin' Sticks. * Taste function assessment with Taste Strips. * Oral trigeminal function assessment with von Frey filaments . * Salivary assessment with the Summated Xerostomia Inventory-Dutch questionnaire. * Salivary flow will be measured using salivary flow rate - stimulated whole saliva (SWS). * A clinical oral examination will be done to obtain a Clinical Oral Dryness Score. * Qualitative smell, taste and trigeminal dysfunction will be assessed using a questionnaire. * Radiological and clinical examinations will be performed to evaluate dental and oral mucosal status. * Quality of life using questionnaire. * Nutritional status using questionnaire. * Magnetic resonance imaging of the brain will be taken to capture regions-of-interest for the three different networks of interest; (i) the gustatory network reflecting changes in taste perception, (ii) the olfactory network, related to the changes in smell, and (iii) the pain matrix reflecting pain. There will be a comparisons between the patients and healthy controls.