ORIGINAL CONTRIBUTION Even cognitively well-functioning adults are unaware of their olfactory dysfunction: Implications for ENT clinicians and researchers* Abstract Background: Past fndings of an impact of cognitive impairment on awareness of olfactory dysfunction, and high prevalence of age-associated cognitive impairment motivated the present study of whether middle-aged and elderly adults are unaware of an olfactory dysfunction despite being carefully screened for cognitive impairment. Methodology: The sample included 203 Norwegian participants, aged 46-79 years, 134 women and 69 men, who underwent comprehensive neuropsychological assessment for screening of cognitive impairment. Subjective assessment of olfactory func- tion (“How would you estimate your sense of smell?”) was compared with outcome on objective assessment of olfactory function with the Scandinavian Odor Identifcation Test, which in the present study was shown to be valid for use on Norwegian populati- ons. Results: We found that 79% of this cognitively healthy sample with objectively assessed olfactory dysfunction reported normal olfactory function (57% of functionally anosmics reported normal function). In contrast, only 9% with objectively assessed normal olfactory function reported olfactory dysfunction. Conclusion: A large proportion of cognitively well-functioning middle-aged and elderly adults with an olfactory dysfunction are unaware of their dysfunction. The ENT physician who suspects that the sense of smell may be compromised should, in addition to an anamnesis, assess the patient’s olfactory function objectively. Key words: aging, olfaction, self-evaluation, unawareness, odour identifcation Eike Wehling 1,2 , Astri J. Lundervold 1,2 , Thomas Espeset 3,4 , Ivar Reinvang 3 , Annika Brämerson 5 , Steven Nordin 6 1 Department of Biological and Medical Psychology, University of Bergen, Norway 2 Kavli Research Centre for Aging and Dementia, Haraldsplass Hospital, Bergen, Norway 3 Department of Psychology, University of Oslo, Norway 4 Norwegian Centre for Mental Disorders Research (NORMENT), and KG Jebsen Centre for Psychosis Research, Division of Mental Health and Addiction, Oslo University Hospital, Norway 5 Department of Otorhinolaryngology, Central Hospital, Skövde, Sweden 6 Department of Psychology, Umeå University, Sweden Rhinology 53: 89-94, 2015 DOI:10.4193/Rhino14.081 *Received for publication: March 23, 2014 Accepted: October 9, 2014 89 Introduction Olfaction can be considered the oldest sensory system from an evolutionary perspective. Therefore, its role and function difers signifcantly from that of the relatively young senses, such as vision and audition. Humans have inherited the basic function of olfaction from very primitive organisms, such that the odour perception from a substance shall either attract us to that subs- tance or make us avoid it, depending on positive or negative as- sociations established at prior interactions with the substance (1) . Since this function was present among very primitive organisms, in which behaviour was largely controlled by instinct, awareness of odour perception is not a prerequisite for olfaction to fulfll its role. Thus, we are typically unconscious of the continuous mo- nitoring we do of the chemical air quality surrounding us, and about the guiding impact that odorous substances have on our behaviour. An advantage of this is that our attention can instead