xRead - Olfactory Disorders (September 2023)

20426984, 2022, 4, Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/alr.22929, Wiley Online Library on [04/09/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License

338

INTERNATIONAL CONSENSUS ON OLFACTION

depression. 26–28 Because of largely shared neural pathways (eg, amygdala, hippocampus, insula, and orbitofrontal cortex [OFC]), 29 this link is not surprising. Croy and Hummel 26 suggest that possible mechanisms behind this association might include that: (1) dysfunction of the OB (as the initial station of olfactory processing) results in decreased neural signaling into subsequent cortices; or (2) the consequence of depressive behavior (eg, withdrawal) leads to diminished olfactory input and consecutive dimin ished OF. Regardless of the mechanisms involved, nega tive feelings such as anhedonia, sadness, fear, or frustration are reported by about one third of patients with olfactory loss, 25,30,31 with varying prevalence attributable to individ ual patient characteristics. For example, higher prevalence has been reported in patients with hyposmia versus those with anosmia, 32 while evidence regarding sex effects is mixed, 32,33 but with women reporting particular effects in social domains. 31 The latter may be explained by the gen erally higher value placed on the sense of smell and impor tance of olfaction in women, in particular young women, compared with other demographic groups. 34 Individuals with reduced self-esteem have been shown to be prone to the emergence of depressive symptoms from olfactory losses. 35 Single reports disclose disturbances in a wide array of life areas, including hygiene behavior, domes tic life, 31 or the enjoyment of simple pleasures, such as the smell of flowers, perfumes, or nature. 20 In view of these reports, the low general QOL measured in these populations is not surprising. However, not every patient with an olfactory disorder is bothered to a substantial degree. It has to be considered that most reported data are obtained from patients seeking help, thus suggesting selection bias. 25,36 In contrast, Oleszkiewicz et al 37 revealed that people with unnoticed olfactory loss do not differ from controls in terms of their well-being. However, within the group of patients disturbed by their sensory loss, concomi tant psychological burden should be carefully assessed and diagnosed. Practitioners should be especially aware of the demographic groups most affected. 38 For such predisposed populations, suitable interventions, eg, consultation with a psychologist or psychiatrist, should be provided in order to prevent manifestation and exacerbation of long-term side effects such as social isolation or anxiety. Interpersonal relationships Human chemosensory signals, such as those released from body odor, convey various data points of informa tion about the individual, which inform sensory social communication. This information reflects hormonal 39 or emotional states, 40–42 personality traits, 43 and the genetic constitution 44 of the releaser. Familiar body odors can sig nal comfort, 45,46 and may be associated with affectionate

B Parosmia Parosmia is defined as a qualitative dysfunction from a distorted perception of smell in the presence of an odor object. 14 These distorted smells are frequently reported to be disgusting or disagreeable and only very rarely would be considered pleasant. Common descriptors include “burned,” “foul,” “disgusting,” and “fecal.” 18–22 Patients often report difficulty in characterizing these odors, and, therefore, these terms should be considered as shorthand for their unpleasantness, rather than definitively accurate descriptions. Parosmic experiences can range from simply “strange” to inducing powerful feelings, such as nausea, and preventing normal food intake. C Phantosmia Phantosmia is defined as a qualitative dysfunction of smell in the absence of an odor object. 14 Here, percep tion of an odor occurs without an external stimulus. Descriptors for phantom odors may be similar in some ways to those used for parosmia: “burned,” “chemical,” and “like cigarette smoke.” 18,20,21,23 It is often difficult for the individual to accept that there is no external source for these perceptions, and they often search their homes or work environments exhaustively seeking the source. Unlike the qualitative changes experienced with parosmia, phantosmic perceptions can occur at any time. Sometimes, both parosmia and phantosmia can occur together in the same patient. 20,23 IV INDIVIDUAL BURDEN OF OD A Psychological sequelae: Potential effects on interpersonal relationships and emotional state The sense of smell serves three core purposes: preven tion of close encounters with environmental hazards, monitoring and guidance of nutrition, and mediation of interpersonal communication. 24 OD hence disturbs functioning of all of those domains. As a consequence, a substantial number of affected individuals state that they experience a poorer overall quality of life (QOL), 25 which particularly affects emotional well-being and interpersonal relationships. Evidence of the costs of smell impairment are summarized below with regard to both aspects (Table IV.1 and Tables IV.2-IV.4). Emotional state Previous research has repeatedly demonstrated associ ations between decreased olfaction and anhedonia or