Quality of life impairment and its assessment in patients with olfactory dysfunction

Olfactory dysfunction (OD) is a frequent medical condition which might determine an important reduction of the patient's quality of life (QoL). The analysis of OD-related QoL may play an important role in clinical practice since the patient's perspectives may influence clinical decisions and could be used to monitor the longitudinal course of individual outcomes. Only a limited number of specific instrument able to evaluate OD-related QoL have been proposed so far and their clinical application is limited. The aim of this review was to analyze the available instruments useful for OD-related QoL measurement in order to increase clinicians' awareness of OD and their ability to evaluate its impact. The Questionnaire of Olfactory Disorders (QOD) is the more widely used but its internal consistency is poor. The Importance of Olfaction Questionnaire demonstrated a good internal consistency but no information regarding its reliability are available. The Self-Administered Odor Questionnaire (SAOQ) demonstrated satisfactory clinical validity and responsiveness to changes but no information regarding its internal consistency and reliability are available. The Scandinavian adaptation of the Multi-Clinic Smell and Taste Questionnaire (MCSTQ-Sc) appears too time consuming. Finally, the Modified Short version of the QOD (MS-QOD) demonstrated satisfactory internal consistency, optimal test re-test reliability and satisfactory discriminant and convergent validity. There is a need for a psychometrically robust, time- and cost-efficient, easy-to-use instrument to be used in everyday clinical practice for the evaluation of the impact of OD on patient's QoL.