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

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INTERNATIONAL CONSENSUS ON OLFACTION

Benefit : Establishing baseline cognition and follow ing this over time in older patients with olfactory deficit greater than that expected for age and no other clear eti ology, allows for earlier recognition of MCI, AD, PD, and other forms of dementia. Harm : Relatively low with potential to incite concern or anxiety about the potential of developing dementia in otherwise healthy individuals. Cost : Direct: Low to moderate monetary cost involving addi tional testing. Indirect: Minimal. Benefits-harm assessment : Preponderance of benefit overharm. Value judgments : Olfactory deficits as well as over all cognition should be compared with peer age groups, as some diminution of ability in both respects is expected with the normal aging process. The olfactory sensory neural pathway includes numer ous brain regions implicated in the pathophysiology of a number of developmentally mediated neuropsychiatric disorders. 26,27,851–874 Notably, in the past two decades, the literature concerning psychophysical OF and its associ ated structural brain, physiological, and clinical corre lates has exponentially grown, providing crucial insights into the developmental and clinical aspects of these neu ropsychiatric disorders. Below is a review of four devel opmentally linked psychiatric disorders including: (1) schizophrenia, (2) autism spectrum disorder (ASD), (3) obsessive-compulsive disorder (OCD), and (4) attention deficit/hyperactivity disorder (ADHD), and findings con cerning psychophysical olfactory functioning in each. Schizophrenia Previous research has provided compelling support for the presence of OD in patients with schizophrenia, with dif fuse impairments among a wide variety of olfactory tasks being evident. 856,875,876 Results revealed moderate to large olfactory deficits in patients with schizophrenia, although significant heterogeneity was observed. Deficits among the psychophysical domains of odor: (1) identification (large effect size), (2) detection threshold (small-moderate effect size), (3) discrimination (moderate effect size), (4) hedo nics (moderate effect size), and (5) memory (large effect size) were seen. Of these five olfactory domains, among K Related to other neurotransmitter disease states (eg, depression, schizophrenia, and autism)

individuals with schizophrenia: (1) older age, (2) being male, (3) greater duration of illness, and (4) medication with typical antipsychotics appeared to be associated with greater olfactory deficit. Autism spectrum disorder Atypical sensory processing issues have been specifically highlighted in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition ( DSM-5 ), diagnostic ASD criteria and have been found to contribute to interper sonal, cognitive, and behavioral problems in this disor der. Despite the latter findings, little attention has been given to chemosensory function in ASD. Review of the literature 874,877 concerning olfactory processing in ASD reveals a generally small to moderate, but homogeneous, pattern of deficits among the domains of odor: (1) iden tification (moderate effect size), (2) detection threshold (small effect size), (3) discrimination (small to moderate effect size), (4) intensity (small effect size), and (5) hedo nics (small effect size). Of these five olfactory domains, among individuals with ASD: (1) younger age, (2) being male, and (3) having lower Full Scale IQ appears to be asso ciated with greater olfactory deficit. Obsessive-compulsive disorder Numerous studies have linked emotions such as dis gust with basic OF, and the underlying neuroanatomy of the olfactory system suggests a link to the pre sumed orbitofrontal pathophysiology of OCD. Review of the literature 877 concerning olfactory processing in OCD revealed a generally moderate to large, but homogeneous, pattern of deficits among the domains of odor: (1) identifi cation (moderate to large effect size), (2) detection thresh old (small to moderate effect size), (3) discrimination (large effect size), (4) intensity (moderate to large effect size), and (5) hedonics (moderate to large effect size). While the lit erature on chemosensory dysfunction in OCD is still in its infancy, this review generally supports that patients with OCD who: (1) were younger, (2) were male, (3) had more severe OCD symptoms, and (4) were taking psychotropic medications demonstrated greater olfactory impairment. Attention-deficit/hyperactivity disorder In ADHD, disruption of olfactory processing is thought to be related to dopamine metabolism and OFC function ing, both known to be involved in the neurobiology of this disorder. Review of the literature 877 concerning olfactory