The Relationship Between Psychopathy and Olfactory Tasks Sensitive to Orbitofrontal Cortex Function in a Non-criminal Student Sample

Olfaction and Executive Cognitive Performance: A Systematic Review

Objective tests of olfaction are widely available to aid in the assessment of olfaction. Their clearest role is in the characterization of olfactory changes, either reported by or suspected in a patient. There is a rapidly growing literature concerned with the association of olfactory changes with certain neuropsychiatric conditions and the use of olfactory testing to supplement conventional assessments in clinical and research practice is evolving. Neural pathways important for olfactory processing overlap extensively with pathways important for cognitive functioning, and especially those important for executive functioning, many of which are concentrated in the frontal lobes. Previous work has identified associations between performance on certain olfactory tests (most frequently olfactory identification) and executive functioning and behavioral measures (e.g. of impulsivity). More recently, similar associations have also been identified in non-clinical samples, raising new questions as to the utility of olfactory test scores as proxy measures for non-olfactory phenomena. In this systemic review, we sought to identify studies, both clinical and non-clinical, that investigated the associations of olfaction with performance on tasks sensitive to frontal lobe functioning. Our search criteria led to the identification of 70 studies published in English. We examined in detail and tabulated the data from these studies, highlighted each study's key findings, and critically evaluated these studies. We use the results of this review to reflect on some of the current and future challenges concerning the use of olfactory testing in clinical neuropsychiatric practice and research and speculate on the potential benefits of administering phonemic fluency in combination with olfactory testing to enhance its predictive value.

Olfactory identification impairment in early-and late-onset obsessive-compulsive disorder

BACKGROUND

Early-onset obsessive-compulsive disorder (EOCD) is a comparatively severe subtype of obsessive-compulsive disorder (OCD). Olfactory dysfunction is a common symptom of OCD, but all previous studies have focused on late-onset OCD (LOCD).

METHODS

The current study compared olfactory identification ability in EOCD patients and age-matched and sex-matched LOCD patients and healthy controls. Thirty patients with EOCD, 30 patients with LOCD and 30 healthy controls were included in the study. Olfactory function was measured using the University of Pennsylvania Smell Identification Test. The Logical Memory and Visual Reproduction components of the Revised Wechsler Memory Scale were used to evaluate verbal and visual memory.

RESULTS

There were significant differences in olfactory identification ability between the three groups. EOCD patients were comparable to LOCD patients, while both patients' group showing worse olfactory identification ability than controls. Olfactory identification ability was not significantly correlated with verbal and visual memory or clinical symptoms in the EOCD group or the LOCD group.

CONCLUSIONS

The results of the present study suggest that olfactory identification ability may be a relatively stable indicator of OCD, independent of age, duration of illness, verbal and visual memory, and severity of clinical symptoms.

The role of body odors and olfactory ability in the initiation, maintenance and breakdown of romantic relationships - A review

The aim of this review is to present direct and indirect lines of converging evidence that highlight the many ways our body odors and sense of smell may influence the three broad stages of romantic relationships; initiation, maintenance and breakdown. This emerging area of study requires a multidisciplinary empirical approach. Here we survey research findings that taken together, suggest that body odor perception moderates mate choice, provides a source of comfort in existing relationships and may signal the breakdown of a relationship through disgust processes. In terms of olfactory ability, having a good sense of smell may facilitate identifying a healthy mate, enhance sexual experiences, relationship security and ensure empathic responsivity, predictors of relationship longevity. We therefore conclude that olfaction plays an important - yet understudied - role in romantic relationships.

Decreased olfactory discrimination is associated with impulsivity in healthy volunteers

In clinical populations, olfactory abilities parallel executive function, implicating shared neuroanatomical substrates within the ventral prefrontal cortex. In healthy individuals, the relationship between olfaction and personality traits or certain cognitive and behavioural characteristics remains unexplored. We therefore tested if olfactory function is associated with trait and behavioural impulsivity in nonclinical individuals. Eighty-three healthy volunteers (50 females) underwent quantitative assessment of olfactory function (odour detection threshold, discrimination, and identification). Each participant was rated for trait impulsivity index using the Barratt Impulsiveness Scale and performed a battery of tasks to assess behavioural impulsivity (Stop Signal Task, SST; Information Sampling Task, IST; Delay Discounting). Lower odour discrimination predicted high ratings in non-planning impulsivity (Barratt Non-Planning impulsivity subscale); both, lower odour discrimination and detection threshold predicted low inhibitory control (SST; increased motor impulsivity). These findings extend clinical observations to support the hypothesis that deficits in olfactory ability are linked to impulsive tendencies within the healthy population. In particular, the relationship between olfactory abilities and behavioural inhibitory control (in the SST) reinforces evidence for functional overlap between neural networks involved in both processes. These findings may usefully inform the stratification of people at risk of impulse-control-related problems and support planning early clinical interventions.