Phantom Smells: Prevalence and Correlates in a Population-Based Sample of Older Adults

Acute phantosmia as the first manifestaton of brain metastases in a patient with breast cancer. Case report

Phantosmia belongs to the group of olfactory dysfunctions. It is more commonly described in psychiatric conditions and some cases of viral infections, but it has been also rarely described in cancer patients who develop primary or metastatic central nervous system tumors; the early identification of this symptom in this population is crucial, as it could lead to timely diagnosis and treatment through a multidisciplinary approach. With the current report we present the case of a 60-year-old lady with metastatic breast cancer and without known preexisting brain metastases, who developed acute phantosmia without other neurological deficits; computed tomography of the brain revealed multiple brain metastases, which were attributed to the malignancy, and for which she was effectively treated with whole brain irradiation and antipsychotic as well as anticonvulsant medications. Furthermore, we underline the value of cooperation between the various specialties that could aid in diagnosis and management of this symptomatology. Phantosmia is an extremely rare symptom in cancer patients, and its appearance should alarm physicians to rapidly investigate a possible progression of disease in the central nervous system. Multidisciplinary approach is needed for the optimal management of these patients.

Giving a Voice to Patients With Smell Disorders Associated With COVID-19: Cross-Sectional Longitudinal Analysis Using Natural Language Processing of Self-Reports

BACKGROUND

Smell disorders are commonly reported with COVID-19 infection. The smell-related issues associated with COVID-19 may be prolonged, even after the respiratory symptoms are resolved. These smell dysfunctions can range from anosmia (complete loss of smell) or hyposmia (reduced sense of smell) to parosmia (smells perceived differently) or phantosmia (smells perceived without an odor source being present). Similar to the difficulty that people experience when talking about their smell experiences, patients find it difficult to express or label the symptoms they experience, thereby complicating diagnosis. The complexity of these symptoms can be an additional burden for patients and health care providers and thus needs further investigation.

OBJECTIVE

This study aims to explore the smell disorder concerns of patients and to provide an overview for each specific smell disorder by using the longitudinal survey conducted in 2020 by the Global Consortium for Chemosensory Research, an international research group that has been created ad hoc for studying chemosensory dysfunctions. We aimed to extend the existing knowledge on smell disorders related to COVID-19 by analyzing a large data set of self-reported descriptive comments by using methods from natural language processing.

METHODS

We included self-reported data on the description of changes in smell provided by 1560 participants at 2 timepoints (second survey completed between 23 and 291 days). Text data from participants who still had smell disorders at the second timepoint (long-haulers) were compared with the text data of those who did not (non-long-haulers). Specifically, 3 aims were pursued in this study. The first aim was to classify smell disorders based on the participants' self-reports. The second aim was to classify the sentiment of each self-report by using a machine learning approach, and the third aim was to find particular food and nonfood keywords that were more salient among long-haulers than those among non-long-haulers.

RESULTS

We found that parosmia (odds ratio [OR] 1.78, 95% CI 1.35-2.37; P<.001) as well as hyposmia (OR 1.74, 95% CI 1.34-2.26; P<.001) were more frequently reported in long-haulers than in non-long-haulers. Furthermore, a significant relationship was found between long-hauler status and sentiment of self-report (P<.001). Finally, we found specific keywords that were more typical for long-haulers than those for non-long-haulers, for example, fire, gas, wine, and vinegar.

CONCLUSIONS

Our work shows consistent findings with those of previous studies, which indicate that self-reports, which can easily be extracted online, may offer valuable information to health care and understanding of smell disorders. At the same time, our study on self-reports provides new insights for future studies investigating smell disorders.

Olfactory Dysfunction in Healthcare Workers with COVID-19: Prevalence and Associated Factors

BACKGROUND

The COVID-19 pandemic is a real global health crisis. Its clinical presentation has evolved over time with an increasing number of symptoms. Olfactory dysfunction (OD) has recently been recognized as a frequent symptom relevant to screening for COVID-19, especially in pauci-asymptomatic forms. However, the underlying mechanisms of OD are not yet fully understood.

AIM

To determine the prevalence of OD in healthcare workers with SARS-CoV-2 and to identify its associated factors.

METHODS

This is a cross-sectional, analytical study, carried out during a period of six months and including all healthcare workers at Farhat Hached Academic Hospital (Tunisia) who were diagnosed with SARS-CoV-2 by PCR, RAT, or chest CT scan.

RESULTS

A total of 474 healthcare workers were included, representing a participation rate of 85.4%. The mean age was 41.02±10.67 years with a sex ratio of 0.2. The distribution of this population by department noted that it was mainly maternity (13.9%). The most presented workstation was nursing (31.4%). OD represented 39.2% of the reasons for consultation. Hospitalization was indicated in 16 patients (3.4%). The average duration of hospitalization was 8.87 ± 7.8 days. The average time off work was 17.04 ± 11.6 days. OD persisted for more than 90 days in 35 patients (7.4%). After multiple binary logistic regression, OD was statistically associated with female gender (p =0.001; OR 95% CI: 2.46 [1.4-4.2]) and blue-collar occupational category (p =0.002; OR IC95%:3.1 [1.5-6.5]). A significant association was also noted between OD and professional seniority and absence from work duration (p =0.019; OR 95% CI: 0.97 [0.95-0.99] and p =0.03; OR 95% CI: 0.97 [0.95-0.99]) respectively.

CONCLUSION

OD is common in COVID-19 patients. The identification of its associated factors may contribute to enhancing the understanding of its mechanism and drive therapeutic options.

Clinical features of chronic fungal rhinosinusitis in Korean geriatric and non-geriatric patients

PURPOSE

Worldwide, the incidence of chronic fungal rhinosinusitis (CFRS) has increased. Although ageing leads to weakening of the immune system, which increases susceptibility to CFRS, the CFRS characteristics in geriatric patients are unclear. Therefore, we comparatively analysed the clinical characteristics of CFRS in geriatric and non-geriatric patients.

METHODS

This retrospective analysis compared the demographics, rhinologic symptoms, multiple allergen simultaneous tests, olfactory function tests, paranasal sinus computed tomography findings, and outcomes of 131 patients with CFRS who underwent functional endoscopic sinus surgery and 131 enrolled patients were divided in geriatric (> 65 years) and non-geriatric (≤ 65 years) groups.

RESULTS

Among the geriatric and non-geriatric participants (n = 65, 49.6% and n = 66, 50.4%, respectively), hypertension and diabetes mellitus were more common in the geriatric group. Demographics, including symptoms, showed no significant intergroup differences. Normosmia and hyposmia were significantly less prevalent, whereas phantosmia and parosmia were more prevalent in the geriatric group than in the non-geriatric group (p = 0.03 and p = 0.01, respectively). Sphenoidal sinus involvement was significantly higher in geriatric patients than in non-geriatric patients (p = 0.02).

CONCLUSION

Based on greater sphenoidal sinus involvement, a deeper anatomical area is more vulnerable to fungal infection in the geriatric group than in the non-geriatric group. Increasing clinicians' awareness of CFRS in geriatric patients with olfactory dysfunction, including phantosmia and parosmia, is important for early intervention.

Comparable responses to a wide range of olfactory stimulation in women and men

The evidence for differences between women and men in terms of olfactory abilities is contradictory. We analyzed women and men's performance and reactions to a wider range of odour exposure outcomes than usually studied, to assess possible differences and similarities between sexes. Measures of sensitivity and sensory decision rule were established in 37 women and 39 men. Perceptual, cognitive, symptom-related and autonomic nervous system (skin conductance level and heart-rate variability) reactions were also assessed during extended ambient odour exposure, as well as participants' self-rated chemical intolerance. Bayesian analyses consistently revealed greater support for sex-related similarities than differences, suggesting that women and men perform and react comparably not only in terms of basic olfactory measures, but also to environmental odour exposure mimicking everyday situations.

Olfactory Function and Olfactory Disorders

The sense of smell is important. This became especially clear to patients with infection-related olfactory loss during the SARS-CoV-2 pandemic. We react, for example, to the body odors of other humans. The sense of smell warns us of danger, and it allows us to perceive flavors when eating and drinking. In essence, this means quality of life. Therefore, anosmia must be taken seriously. Although olfactory receptor neurons are characterized by regenerative capacity, anosmia is relatively common with about 5 % of anosmic people in the general population. Olfactory disorders are classified according to their causes (e. g., infections of the upper respiratory tract, traumatic brain injury, chronic rhinosinusitis, age) with the resulting different therapeutic options and prognoses. Thorough history taking is therefore important. A wide variety of tools are available for diagnosis, ranging from short screening tests and detailed multidimensional test procedures to electrophysiological and imaging methods. Thus, quantitative olfactory disorders are easily assessable and traceable. For qualitative olfactory disorders such as parosmia, however, no objectifying diagnostic procedures are currently available. Therapeutic options for olfactory disorders are limited. Nevertheless, there are effective options consisting of olfactory training as well as various additive drug therapies. The consultation and the competent discussion with the patients are of major importance.

The Role of BDNF as a Biomarker in Cognitive and Sensory Neurodegeneration

Brain-derived neurotrophic factor (BDNF) has a crucial function in the central nervous system and in sensory structures including olfactory and auditory systems. Many studies have highlighted the protective effects of BDNF in the brain, showing how it can promote neuronal growth and survival and modulate synaptic plasticity. On the other hand, conflicting data about BDNF expression and functions in the cochlear and in olfactory structures have been reported. Several clinical and experimental research studies showed alterations in BDNF levels in neurodegenerative diseases affecting the central and peripheral nervous system, suggesting that BDNF can be a promising biomarker in most neurodegenerative conditions, including Alzheimer's disease, shearing loss, or olfactory impairment. Here, we summarize current research concerning BDNF functions in brain and in sensory domains (olfaction and hearing), focusing on the effects of the BDNF/TrkB signalling pathway activation in both physiological and pathological conditions. Finally, we review significant studies highlighting the possibility to target BDNF as a biomarker in early diagnosis of sensory and cognitive neurodegeneration, opening new opportunities to develop effective therapeutic strategies aimed to counteract neurodegeneration.

Phantosmia: A neglected symptom after Dacryocystorhinostomy with intubation (A case report)

A 62-year-old female presented with complaints of persistent phantosmia (foul smell) for the last 4 months. She has a past history of right-sided dacryocystorhinostomy (DCR) 18 months back and left-sided DCR 12 months back. In the initial follow-up period, the patient had frequent visits to her otolaryngologist and ophthalmologist. She experienced phantosmia often but was reassured. The patient presented to us and was examined in an operation theater. It was discovered that the foul-smelling foreign body was present in her right nasal cavity above the middle turbinate. It was removed. A retained gauze piece was revealed to be a cause of phantosmia. The purpose of reporting is to create awareness among ophthalmologists and otolaryngologists. Retained gauze piece following DCR surgery presenting as phantosmia is a new symptom after DCR surgery previously not reported in the literature. Repeated complaints of a postoperative patient, should be dealt with vigilantly and timely.

Parosmia and Phantosmia: Managing Quality Disorders

Purpose of Review

The purpose of this review was to summarize the current knowledge on parosmia and phantosmia and introduce support and treatment algorithms for the two qualitative olfactory disorders.

Recent Findings

Recent literature regarding parosmia has revealed that patients with the disorder are mainly triggered by certain substances, including thiols and pyrazines. In 2015, the existing "olfactory training" regimen was improved to more effectively treat post-infectious olfactory loss and was named "modified olfactory training" (MOT). It was also found in 2022 that MOT is also effective against COVID-19-induced parosmia.

Summary

Parosmia, the distortion of smells, is a symptom in qualitative olfactory disorders that severely affects patients' mental well-being and enjoyment of their everyday lives. The condition was first documented in 1895 and can affect up to 5% of the general population. Etiologies of parosmia include sinonasal diseases, viruses, surgeries, traumatic brain injury, neurological and psychiatric conditions, toxic chemicals, and medications. Parosmia has seen a surge in cases since the onset of the COVID-19 pandemic and is linked to changes in brain structure following an infection. The evaluation of the symptom is done using surveys, smell identification tests, fMRI, MRI, PET/CT, and gas chromatography. Treatment for parosmia can vary in duration, which makes it essential to focus not only on helping the patients regain normosmia, but also on supporting the patient through the recovery journey. Parosmia should not be confused with phantosmia, in which the distortion of smells occurs in the absence of olfactory stimuli. The etiology of phantosmia can vary from infections and traumatic brain injury to psychiatric disorders like schizophrenia. Unlike parosmia, the treatment of phantosmia is less straightforward, with an emphasis on determining the etiology and providing symptomatic relief.

Disgust-Eliciting Pathogen Threats and Salivary Immune Responses

Abstract. This study aimed to examine the effects of different sensory modality presentations of disgusting stimuli on aspects of immunity (behavioral and physiological) and affect in men and women. Sixty-four college students participated, and all participants were randomly assigned to one of four groups based on sensory modality stimuli type (visual or olfactory) and manipulation (experimental or control). Results indicated that olfactory stimuli were rated as more disgusting than visual stimuli. When collapsed across sensory modality, females tended to self-report greater disgust sensitivity than males. Overall, there was a significant negative association between disgust ratings and changes in resting heart rate (HR). Baseline salivary immunoglobulin A (SIgA) concentration was significantly positively correlated with disgust ratings in men. Our findings suggest that the behavioral and physiological immune systems are indeed coordinated, but future studies are needed to examine the extent to which multisensory disgusting cues influence immune system responses as a function of gender.

Occurrence and phenomenology of hallucinations in the general population: A large online survey

Although epidemiological studies report that hallucinations occur in 6–15% of the general population, little is known about their phenomenology. To overcome this paucity, this study investigates the phenomenological characteristics of hallucinations in the general population, by using a nationally promoted online survey to assess hallucination phenomenology in four sensory modalities, through a self-report version of the Questionnaire for Psychotic Experiences (QPE), in 10,448 participants (aged 14–88 years). The phenomenology of hallucinations was assessed if hallucinations reportedly occurred in the past month. In the past month, auditory hallucinations were reported most frequently (29.5%), followed by visual (21.5%), tactile (19.9%), and olfactory hallucinations (17.3%); hallucinations in two or more modalities were reported by 47.6%. Substantial numbers of participants rated their hallucinations as severe, due to negative content (16.0–31.6%), previous bothersome experiences (14.8–20.2%), ensuing distress (10.5–16.8%), and/or ensuing disfunctioning (12.7–17.3%). Decreased insight was found in 10.2–11.4%. Hypnagogia was reported by 9.0–10.6%, and bereavement hallucinations by 2.8%. Despite a low prevalence of delusions (7.0%), these phenomena were significantly associated with recent hallucinations, observed in up to 13.4% of the participants with hallucinations during the past week (p < 0.001). Our results indicate a wide variety of the phenomenology of hallucinations in the general population and support the existence of a phenomenological continuum.

Various presentations of the olfactory hallucination in two patients with migraine disease: Case report

OBJECTIVES

To report two different presentations of migraine with the olfactory hallucinations. A case with the typical hallucinatory olfactory symptoms preceding migraine headaches and another case with longstanding olfactory hallucinations.

BACKGROUND

Migraine prevails in about 12% of the general population, with the migraine aura accountable for at least one-third of these cases. The most common aura is the visual aura, followed by the sensory aura, speech, and motor auras. Olfactory hallucinations preceding the headache phase of migraine are rare. To date, the International Classification of Headache Disorders (ICHD) has not recognized them as a subset of migraine aura.

RESULTS

This report presents a patient with a typical Phantosmia (PO) aura before her migraine headache and a patient who experiences a longstanding PO aura.

CONCLUSION

The olfactory hallucination may present differently in patients with migraine disease. Based on the clinical significance of migraine with olfactory hallucinations, we propose that the ICHD classify this phenomenon as a subtype of aura in the future. However, larger studies are still required to better assess the pathophysiology of this phenomenon.

Phantom smells: a prevalent COVID-19 symptom that progressively sets in

PURPOSE

One of the long-term symptoms of COVID-19 is phantosmia, a type of Olfactory Disorder (OD) that has deleterious impacts on patients' quality of life. The aim of this article was to study how this poorly understood qualitative OD manifests itself in the COVID-19.

METHODS

4691 patients with COVID-19 responded to our online questionnaire focusing on COVID-19-related OD. We first analyzed the prevalence of phantosmia in this population. Then, with the help of Natural Language Processing techniques, we investigated the qualitative descriptions of phantom smells by the 1723 respondents who reported phantosmia.

RESULTS

The prevalence of phantosmia was of 37%. Women were more likely to report phantosmia than men, as well as respondents for whom OD was described as fluctuating rather than permanent, lasted longer, was partial rather than total and appeared progressively rather than suddenly. The relationship between OD duration and phantosmia followed a logarithmic function, with a prevalence of phantosmia increasing strongly during the first 2 months of the disease before reaching a plateau and no decrease over the 15 months considered in this study. Qualitative analyses of phantosmia descriptions with a sentiment analysis revealed that the descriptions were negatively valenced for 78% of the respondents. Reference to "tobacco" was more frequent in non-smokers. Source names and odor characteristics were used differently according to age and OD duration.

CONCLUSION

The results of this descriptive study of phantosmia contribute to the current efforts of the medical community to better understand and treat this rapidly increasing COVID-19-related OD.

Headache-Associated Phantosmia as a Harbinger of Lewy Body Dementia

Olfactory hallucinations, or phantosmias, can occur in many neurological, psychiatric, and medical conditions, but no widely used standardized approach exists to comprehensively assess qualitative olfactory dysfunction in the clinical setting. Additionally, medical professionals, patients, and their family members may not recognize phantosmia as a potentially neurological problem. Given the many possible etiologies for symptomatic phantosmia, it is important to recognize this unusual presentation and elicit a meaningful history to explore the potential underlying cause. We describe a 77-year-old gentleman with a two-year history of headaches accompanied by smelling a foul odor and discuss the differential diagnosis for new onset and persistent phantosmia. This unusual case ultimately manifested features consistent with Lewy body dementia, highlighting the varied clinical presentations that are possible with this neurodegenerative disorder. We discuss the possible pathophysiology of phantosmia in Lewy body disorders, including a proposed mechanism for olfactory hallucinations arising prior to the typical well-formed hallucinations in Lewy body dementia.

Olfactory Bulb Integrity in Frontotemporal Dementia and Alzheimer’s Disease

Background: Olfactory dysfunction is highly prevalent in dementia syndromes, including Alzheimer’s disease (AD) and frontotemporal dementia (FTD). The structural integrity of the olfactory bulb (OB) is thought to play a critical role in odor detection and identification, but no MRI study has measured OB volume in FTD, or measured OB volume longitudinally in AD. Objective: To measure OB volume in FTD and AD patients longitudinally using MRI. Methods: This study measured OB volumes using MRI in patients diagnosed with behavioral-variant FTD (n = 55), semantic dementia (n = 34), progressive non-fluent aphasia (n = 30), AD (n = 50), and healthy age-matched controls (n = 55) at their first visit to a dementia research clinic (‘baseline’). Imaging data in patients 12-months later were analyzed where available (n = 84) for longitudinal assessment. Volumes of subcortical and cortical olfactory regions (‘olfactory network’) were obtained via surface-based morphometry. Results: Results revealed that in AD and FTD at baseline, OB volumes were similar to controls, whereas volumes of olfactory network regions were significantly reduced in all patient groups except in progressive non-fluent aphasia. Longitudinal data revealed that OB volume became significantly reduced (10–25% volume reduction) in all dementia groups with disease progression. Conclusion: Olfactory dysfunction is common in patients diagnosed with AD or FTD, but our results indicate that there is no detectable volume loss to the OBs upon first presentation to the clinic. Our findings indicate that the OBs become detectably atrophied later in the disease process. OB atrophy indicates the potential usefulness for OBs to be targeted in interventions to improve olfactory function.

Olfactory distortions in the general population

Parosmia, distorted smell sensations, is a common consequence of respiratory virus infections. The phenomenon is not well understood in terms of its impact and long-term outcomes. We examined self-reported experiences of parosmia in a population-based sample from the Betula study that was conducted in Umeå in northern Sweden (baseline data collected in 1998–2000). We used a baseline sample of 2168 individuals aged 35–90 years and with no cognitive impairment at baseline. We investigated the prevalence of parosmia experiences and, using regression analyses, its relationship to other olfactory and cognitive variables and quality of life. Benefitting from the longitudinal study design, we also assessed the persistence of parosmia over 5 and 10 years prospectively. Parosmia experiences were prevalent in 4.8% of the population and it often co-occurred with phantosmia (“olfactory hallucinations”), but was not associated with lower self-rated overall quality of life or poor performance on olfactory or cognitive tests. For some individuals, parosmia was retained 5 years (17.0%) or even 10 years later (10.3%). Thus, parosmia experiences are commonly reported in the population, and can be persistent for some individuals, but might be mostly benign in nature. Our work complements research on clinical-level parosmia, which is typically more severe, and recent parosmia reports during the COVID-19 pandemic, where long-term outcomes are still unknown.

International consensus statement on allergy and rhinology: Olfaction

BACKGROUND

The literature regarding clinical olfaction, olfactory loss, and olfactory dysfunction has expanded rapidly over the past two decades, with an exponential rise in the past year. There is substantial variability in the quality of this literature and a need to consolidate and critically review the evidence. It is with that aim that we have gathered experts from around the world to produce this International Consensus on Allergy and Rhinology: Olfaction (ICAR:O).

METHODS

Using previously described methodology, specific topics were developed relating to olfaction. Each topic was assigned a literature review, evidence-based review, or evidence-based review with recommendations format as dictated by available evidence and scope within the ICAR:O document. Following iterative reviews of each topic, the ICAR:O document was integrated and reviewed by all authors for final consensus.

RESULTS

The ICAR:O document reviews nearly 100 separate topics within the realm of olfaction, including diagnosis, epidemiology, disease burden, diagnosis, testing, etiology, treatment, and associated pathologies.

CONCLUSION

This critical review of the existing clinical olfaction literature provides much needed insight and clarity into the evaluation, diagnosis, and treatment of patients with olfactory dysfunction, while also clearly delineating gaps in our knowledge and evidence base that we should investigate further.

Short duration phantosmia changes in a post-COVID-19 patient in Bangladesh

Phantosmia is a condition in perceived odors that do not exist. Given the high outlook and swift recovery of COVID-19-induced olfactory dysfunction, the emphasis should be on patients presenting with a poor prognosis who might receive from early management to avoid sequelae such as olfactory dysfunction-related phantosmia.

First-episode olfactory hallucination in a patient with anxiety disorder: A case report

BACKGROUND

Olfactory hallucination refers to olfactory perception in the absence of chemical stimuli. Although it has been associated with many neurological and psychotic disorders, it has rarely been reported as the first and only symptom in patients with anxiety disorder, and its treatment remains inadequate.

CASE SUMMARY

A 66-year-old woman who had been experiencing gradually worsening olfactory hallucinations for almost 4 years was diagnosed with generalized anxiety disorder. Olfactory hallucination disappeared after treatment with anti-anxiety drugs.

CONCLUSION

Olfactory hallucination can be the first and only symptom in patients with anxiety disorder and may be effectively treated with anti-anxiety medication. In fact, it can precede the diagnosis of anxiety disorder by several years.

Olfaction in COPD

BACKGROUND

Olfaction is poorly characterized in COPD. To test the hypothesis that olfaction is reduced in COPD, we assessed olfaction with the "Sniffin' Sticks" test and a questionnaire addressing olfaction in COPD and a corresponding control group in respect to age and sex. We also explored whether there is an association between COPD, chronic rhinosinusitis without nasal polyps (CRSsNP), and other predefined covariates with olfactory function.

METHODOLOGY

Olfactory function was assessed by the score for threshold (T), discrimination (D) and identification (I), and the composite TDI score in the "Sniffin' Sticks" test and by self-reported evaluation of impaired olfaction and of "decreased sense of smell and taste" in the 22-item Sino-Nasal Outcome Test (SNOT-22) in 90 COPD patients and 93 controls. A clinical interview and ENT-examination with nasal endoscopy, skin prick test and spirometry with reversibility were performed.

RESULTS

The TDI, D and I scores were significantly lower in the COPD group than in the control group. The T score was not significantly different between the two groups. Hyposmia and anosmia were present in up to 79% of patients with COPD. The prevalence of self-reported impaired olfactory function and for "decreased sense of smell and taste&quot; - was more than two-fold greater in the COPD than in the control group. COPD, higher age, male sex and allergy were associated with a lower TDI score, while CRSsNP was not associated with the TDI score.

CONCLUSIONS

COPD is associated with olfactory dysfunction and the underlying mechanisms for this dysfunction should be elucidated.

Olfactory hallucinations in a population-based sample

Olfactory hallucinations referring to olfactory perceptions in the absence of chemical stimuli, occur in non-clinical and clinical populations. Few studies have investigated their prevalence in the general population and little is known about factors triggering and maintaining them such as substance use, severe life events, and mood. We analyzed self-report data from 2500 community dwelling Norwegians, aged 18-96 years, for occurrence of olfactory hallucinations and co-occurring hallucinations in other modalities (auditory, visual, tactile). Analyses included age, sex, self-reported symptoms of depression and anxiety, mental health status, and experience of severe life-events. The results show that 4.2% (95% CI 3.5-5.1%) reported having experienced olfactory hallucinations, and 56% of individuals experiencing olfactory hallucinations also reported these in combination with hallucinations in other modalities. Prevalence varied significantly in terms of age and sex, in that olfactory hallucinations were most frequently reported by young individuals and females. Self-reported symptoms of anxiety and experience of stressful life events were significantly associated with olfactory hallucinations, suggesting that experiencing olfactory hallucinations may negatively affect functioning and may increase the likelihood of developing psychopathology. Findings underline the need to continue to examine olfactory hallucinations albeit with a more comprehensive assessment in order to increase knowledge on this experience.

Frequency and Determinants of Olfactory Hallucinations in Parkinson's Disease Patients

Background: Olfactory dysfunctions and hallucinations are considered common nonmotor symptoms in Parkinson’s disease (PD). Visual and auditory hallucinations are well-known; however, olfactory hallucinations (OHs) are not fully investigated. The aim of this study was to evaluate OHs in PD patients, and their correlation to motor impairment, cognitive abilities, visual and auditory hallucinations, and olfactory and gustatory function. Methods: A sample of 273 patients was enrolled: 141 PD patients (mean age ± SD: 70.1 ± 9.5 years) and 132 healthy controls (mean age ± SD: 69.4 ± 9.6 years). In all patients, the following parameters were evaluated: motor symptoms (UPDRS-III), olfactory function, cognitive abilities, and occurrence of OH, gustatory hallucinations (GHs), and visual/auditory hallucinations. Results: OHs were found only in PD patients with a percentage of 11.3%. Among PD patients with OHs, 2.8% also presented GHs. High significant frequencies of females, the presence of visual/auditory hallucinations, and a high mean UPDRS-III score were found in patients with OHs related to patients without them. Binary logistic regression evidenced the presence of visual/auditory hallucinations and sex as main variables predicting the presence of OHs. Conclusions: Our data indicated that OHs occur frequently in PD patients, especially in women, and often concomitant with visual and auditory hallucinations, without any association with olfactory impairment.

Consequences of gaining olfactory function after lifelong anosmia

We present a rare case in which a patient has gained her smell after lifelong anosmia. The patient was objectively tested and diagnosed with functional anosmia at age 13 and reported they were experiencing a new sensation of smell at age 22. Our results show an electrophysiological signal for two unimodal odorants. The patient had a retronasal score in the hyposmic range and self-reported the ability to smell non-trigeminal odors, but reported being disturbed by the presence of the new sense and co-occurrence of phantosmia. We discuss our case in routes of neurogenesis and non-forming memory association with odors.

Phantosmia with COVID-19 Related Olfactory Dysfunction: Report of Nine Case

Phantosmia has been described as a sense of smell without a true stimulating odor and not been reported with COVID-19 disease. Nine patients admitted to Ear Nose Throat (ENT) Clinic with complaints of a phantom smell sense after an average of 33.5 ± 9.5 days after the initial PCR diagnosis. According to the Sniffin 'Sticks test, phantosmia was associated with objective hyposmia in three patients with the persistent phantom smell, and other six patients were detected normosmic. Phantosmia or olfactory hallucinations have not been previously associated with COVID-19 disease. Additionally, COVID-19 related phantosmia showed different characteristics according to described in the literature.

Chemosensory Dysfunctions Induced by COVID-19 Can Persist up to 7 Months: A Study of Over 700 Healthcare Workers

Several studies have revealed either self-reported chemosensory alterations in large groups or objective quantified chemosensory impairments in smaller populations of patients diagnosed with COVID-19. However, due to the great variability in published results regarding COVID-19-induced chemosensory impairments and their follow-up, prognosis for chemosensory functions in patients with such complaints remains unclear. Our objective is to describe the various chemosensory alterations associated with COVID-19 and their prevalence and evolution after infection. A cross-sectional study of 704 healthcare workers with a RT–PCR-confirmed SARS-CoV-2 infection between 2020 February 28 and 2020 June 14 was conducted 3–7 months after onset of symptoms. Data were collected with an online questionnaire. Outcomes included differences in reported chemosensory self-assessment of olfactory, gustatory, and trigeminal functions across time points and Chemosensory Perception Test scores from an easy-to-use at-home self-administered chemosensory test. Among the 704 participants, 593 (84.2%) were women, the mean (SD) age was 42 (12) years, and the questionnaire was answered on average 4.8 (0.8) months after COVID-19. During COVID-19, a decrease in olfactory, gustatory, and trigeminal sensitivities was reported by 81.3%, 81.5%, and 48.0%, respectively. Three to 7 months later, reduced sensitivity was still reported by 52.0%, 41.9%, and 23.3%, respectively. Chemosensory Perception Test scores indicate that 19.5% of participants had objective olfactory impairment. These data suggest a significant proportion of COVID-19 cases have persistent chemosensory impairments at 3–7 months after their infection, but the majority of those who had completely lost their olfactory, gustatory, and trigeminal sensitivities have improved.

Prevalence and correlates of parosmia and phantosmia among smell disorders

Among those many individuals who experience a reduced odor sensitivity (hyposmia/anosmia), some individuals also have disorders that lead to odor distortion, such as parosmia (i.e. distorted odor with a known source), or odor phantoms (i.e. odor sensation without an odor source). We surveyed a large population with at least one olfactory disorder (N = 2031) and found that odor distortions were common (46%), with respondents reporting either parosmia (19%), phantosmia (11%), or both (16%). In comparison to respondents with hyposmia or anosmia, respondents with parosmia were more likely to be female, young, and suffering from post-viral olfactory loss (P < 0.001), while respondents with phantosmia were more likely to be middle-aged (P < 0.01) and experiencing symptoms caused by head trauma (P < 0.01). In addition, parosmia, compared to phantosmia or anosmia/hyposmia, was most prevalent 3 months to a year after olfactory symptom onset (P < 0.001), which coincides with the timeline of physiological recovery. Finally, we observed that the frequency and duration of distortions negatively affects the quality of life, with parosmia showing a higher range of severity than phantosmia (P < 0.001). Previous research often grouped these distortions together, but our results show that they have distinct patterns of demographics, medical history, and loss in quality of life.

The association of frailty with olfactory and gustatory dysfunction in older adults: a nationally representative sample

BACKGROUND

Olfaction and gustation are associated with age-related decline. Deficits in these chemosenses have been associated with significant comorbidities. Meanwhile, frailty, defined as a reduced physiological reserve, is well correlated with mortality and worse health outcomes. We sought to analyze a nationally representative patient population to determine the association between chemosensory dysfunction and frailty.

METHODS

Cross-sectional analysis of U.S. National Health and Nutrition Examination Survey (NHANES) 2013-2014 was performed, using multivariate logistic regression to examine the association between chemosensory dysfunction and frailty in adults aged ≥40 years (n = 3547). Self-reported olfactory dysfunction (sOD) and gustatory dysfunction (sGD), and measured olfactory dysfunction (mOD) and gustatory dysfunction (mGD) were assessed for all participants. Frailty was operationalized using a 39-item frailty index (FI) and stratified into 4 groups using validated cutoffs.

RESULTS

Participants with sOD and mOD had significantly higher mean FI scores (sOD: 0.18 vs 0.13, p < 0.001; mOD: 0.20 vs 0.14, p < 0.001), whereas subjects with sGD, but not mGD, had higher mean FI scores (sGD: 0.21 vs 0.13, p < 0.001; mGD: 0.14 vs 0.14, p = 0.953). Multivariate logistic regression demonstrated frail participants had significantly greater odds of sGD (odds ratio [OR] 4.11; 95% confidence interval [CI], 3.46 to 4.88), sOD (OR 2.35; 95% CI, 1.98 to 2.78), and mOD (OR 1.58; 95% CI, 1.22 to 2.05), but not mGD (OR 1.21; 95% CI, 0.91 to 1.61). This association was strongest in the frailest group.

CONCLUSION

Self-reported chemosensory dysfunction and mOD are independently associated with measures of frailty, suggesting a novel method to assess or predict frailty.

Assessment of odor hedonic perception: the Sniffin' sticks parosmia test (SSParoT)

Qualitative olfactory dysfunction is characterized as distorted odor perception and can have a profound effect on quality of life of affected individuals. Parosmia and phantosmia represent the two main subgroups of qualitative impairment and are currently diagnosed based on patient history only. We have developed a test method which measures qualitative olfactory function based on the odors of the Sniffin' Sticks Identification subtest. The newly developed test is called Sniffin' Sticks Parosmia Test (SSParoT). SSParoT uses hedonic estimates of two oppositely valenced odors (pleasant and unpleasant) to assess hedonic range (HR) and hedonic direction (HD), which represent qualitative olfactory perception. HR is defined as the perceivable hedonic distance between two oppositely valenced odors, while HD serves as an indicator for overall hedonic perception of odors. This multicenter study enrolled a total of 162 normosmic subjects in four consecutive experiments. Cluster analysis was used to group odors from the 16-item Sniffin' Sticks Identification test and 24-additional odors into clusters with distinct hedonic properties. Eleven odor pairs were found to be suitable for estimation of HR and HD. Analysis showed agreement between test-retest sessions for all odor pairs. SSparoT might emerge as a valuable tool to assess qualitative olfactory function in health and disease.

Prescription Medication Use and Phantom Odor Perception Among US Adults

INTRODUCTION

Prescription medication use may be associated with phantom odor perception. We evaluated associations between number of prescription medications and their therapeutic class and phantom odor perception among U.S. adults.

METHODS

Data were collected between 2011-2014 as part of the National Health and Nutrition Examination Survey (NHANES). A complex sampling design resulted in a nationally representative sample of 7,417 adults aged 40 years and older. During an in-home interview, participants were asked whether they had experienced an unpleasant, bad, or burning odor when nothing is there. Prescription medication use was assessed using validation with prescription bottles, when possible.

RESULTS

Almost one quarter (23.3%) of adults uses ≥5 prescription medications. Use of five or more prescription medications is associated with 70% greater odds of phantom odor perception (OR 1.69 (1.09, 2.63)). Among adults 60 years and older, antidiabetic medications, antihyperlipidemic agents, and proton pump inhibitors are associated with 74-88% greater odds of report of phantom odor [OR=1.74 (1.09, 2.77), OR=1.85 (1.22. 2.80), and OR=1.88 (1.15, 3.07)], respectively.

CONCLUSIONS

Phantom odor perception may be a side effect of antidiabetic or antihyperlipidemic agents. Among people taking proton pump inhibitors, phantom odors may also be a consequence of gastric gas reflux.

IMPLICATIONS

Common prescription medications may be providing an olfactory stimulus.

Olfactory dysfunction in frontotemporal dementia and psychiatric disorders: A systematic review

Frontotemporal dementia (FTD) is a progressive neurodegenerative disease. Diagnosis of FTD, especially the behavioural variant, is challenging because of symptomatic overlap with psychiatric disorders (depression, schizophrenia, bipolar disorder). Olfactory dysfunction is common in both FTD and psychiatric disorders, and often appears years before symptom onset. This systematic review analysed 74 studies on olfactory function in FTD, depression, schizophrenia and bipolar disorder to identify differences in olfactory dysfunction profiles, focusing on the most common smell measures: odour identification and discrimination. Results revealed that FTD patients were severely impaired in odour identification but not discrimination; in contrast, patients diagnosed with schizophrenia showed impairments in both measures, while those diagnosed with depression showed no olfactory impairments. Findings in bipolar disorder were mixed. Therefore, testing odour identification and discrimination differentiates FTD from depression and schizophrenia, but not from bipolar disorder. Given the high prevalence of odour identification impairments in FTD, and that smell dysfunction predicts neurodegeneration in other diseases, olfactory testing seems a promising avenue towards improving diagnosis between FTD and psychiatric disorders.

Hallucinations in Older Adults: A Practical Review

Older adults experience hallucinations in a variety of social, physical, and mental health contexts. Not everyone is open about these experiences, as hallucinations are surrounded with stigma. Hence, hallucinatory experiences in older individuals are often under-recognized. They are also commonly misunderstood by service providers, suggesting that there is significant scope for improvement in the training and practice of professionals working with this age group. The aim of the present article is to increase knowledge about hallucinations in older adults and provide a practical resource for the health and aged-care workforce. Specifically, we provide a concise narrative review and critique of (1) workforce competency and training issues, (2) assessment tools, and (3) current treatments and management guidelines. We conclude with a brief summary including suggestions for service and training providers and future research.

Associations between Cadmium Exposure and Taste and Smell Dysfunction: Results from the National Health and Nutrition Examination Survey (NHANES), 2011-2014

Background: Cadmium is a ubiquitous environmental pollutant and has been associated with many adverse health outcomes. However, little is known about the effect of cadmium exposure on taste and smell dysfunction. Methods: We used the National Health and Nutrition Examination Survey (NHANES) 2011–2014 to investigate the associations between blood cadmium and taste and smell dysfunction among 5038 adults aged 40–80 years old. Taste and smell dysfunction were defined by questionnaires, examinations, or both criteria. Results: In survey weighted logistic regression models adjusting for age, gender, race/ethnicity, income-to-poverty ratio (IPR), and education, individuals with a blood cadmium level in the highest tertiles had significantly higher odds of having perceived smell dysfunction (odds ratio (OR) = 1.41, 95% confidence interval (CI): 1.08, 1.84), perceived taste dysfunction (OR = 1.48, 95% CI: 1.16, 1.89), and taste dysfunction defined by both self-reported and objectively measured data (OR = 1.46, 95% CI: 1.03, 2.07). After further adjusting for body mass index (BMI), cigarette smoking, and alcohol drinking, consistent results were observed for perceived taste dysfunction (OR = 1.49, 95% CI: 1.10, 2.00), and no significant associations were found between cadmium exposure and other outcomes. Conclusions: Our findings suggest that cadmium exposure is associated with perceived taste dysfunction.

Factors Associated With Phantom Odor Perception Among US Adults: Findings From the National Health and Nutrition Examination Survey

Importance

Phantom odor perception can be a debilitating condition. Factors associated with phantom odor perception have not been reported using population-based epidemiologic data.

Objective

To estimate the prevalence of phantom odor perception among US adults 40 years and older and identify factors associated with this condition.

Design, Setting, and Participants

In this cross-sectional study with complex sampling design, 7417 adults 40 years and older made up a nationally representative sample from data collected in 2011 through 2014 as part of the National Health and Nutrition Examination Survey.

Exposures

Sociodemographic characteristics, cigarette and alcohol use, head injury, persistent dry mouth, smell function, and general health status.

Main Outcomes and Measures

Phantom odor perception ascertained as report of unpleasant, bad, or burning odor when no actual odor exists.

Results

Of the 7417 participants in the study, 52.8% (3862) were women, the mean (SD) age was 58 (12) years, and the prevalence of phantom odor perception occurred in 534 participants, which was 6.5% of the population (95% CI, 5.7%-7.5%). Phantom odor prevalence varied considerably by age and sex. Women 60 years and older reported phantom odors less commonly (7.5% [n = 935] and 5.5% [n = 937] among women aged 60-69 years and 70 years and older, respectively) than younger women (9.6% [n = 1028] and 10.1% [n = 962] among those aged 40-49 years and 50-59 years, respectively). The prevalence among men varied from 2.5% (n = 846) among men 70 years and older to 5.3% (n = 913) among men 60 to 69 years old. Phantom odor perception was 60% (n = 1602) to 65% (n = 2521) more likely among those with an income-to-poverty ratio of less than 3 compared with those in the highest income-to-poverty ratio group (odds ratio [OR], 1.65; 95% CI, 1.06-2.56; and OR, 1.60; 95% CI, 1.01-2.54 for income-to-poverty ratio <1.5 and 1.5-2.9, respectively). Health conditions associated with phantom odor perception included persistent dry mouth (OR, 3.03; 95% CI, 2.17-4.24) and history of head injury (OR, 1.74; 95% CI, 1.20-2.51).

Conclusions and Relevance

An age-related decline in the prevalence of phantom odor perception is observed in women but not in men. Only 11% (n = 64) of people who report phantom odor perception have discussed a taste or smell problem with a clinician. Associations of phantom odor perception with poorer health and persistent dry mouth point to medication use as a potential explanation. Prevention of serious head injuries could have the added benefit of reducing phantom odor perception.

Phantom odor perception and vascular conditions among adults in the United States: National Health and Nutrition Examination Survey 2011-2014

OBJECTIVES/HYPOTHESIS

Phantom odor perception has been correlated with burden of vascular risk among older adults. We evaluated associations between vascular conditions and phantom odor perception among adults in the United States.

STUDY DESIGN

Cross-sectional analysis.

METHODS

Cross-sectional data were collected as part of the 2011 to 2014 National Health and Nutrition Examination Survey, yielding a nationally representative sample of 7,417 adults aged 40 years and older. Phantom odor perception was defined as report of an unpleasant, bad, or burning odor when nothing is there. Participants reported on vascular conditions including history of stroke. Total cholesterol and glycated hemoglobinwere measured. High blood pressure was ascertained during an examination.

RESULTS

Stroke was associated with a 76% greater likelihood of phantom odor perception. Congestive heart failure and angina were associated with three times and 2.8 times the odds of phantom odor perception among adults 40 to 59 years and 60 years and older, respectively. Adults with diagnosed, but controlled, high cholesterol reported phantom odors more frequently than those without high cholesterol. Adults with diagnosed, but controlled, high blood pressure reported phantom odors more frequently than those without high blood pressure. We observed a threefold greater odds of phantom odor perception among adults aged 60 years and older with diabetes, but only among those who use both insulin and oral medications.

CONCLUSIONS

Stroke, angina, congestive heart failure, well-managed high blood pressure, and well-managed high cholesterol are associated with phantom odor perception. Vascular or metabolic conditions or their treatments may contribute to reporting of phantom odor perception.

LEVEL OF EVIDENCE

NA Laryngoscope, 130:332-337, 2020.

Heightened olfactory dysfunction and oral irritation among chronic smokers and heightened propylthiouracil (PROP) bitterness among menthol smokers

Chronic cigarette smoking may influence chemosensory function, which in turn, may affect cigarette usage. Because menthol in cigarettes can attenuate nicotine bitterness, choice of menthol/nonmenthol cigarettes may be influenced by ability to perceive bitterness. We examined chemosensory function of chronic smokers, hypothesizing they would show altered function in comparison to non-smokers and by menthol cigarette preference. In laboratory-based measures, chronic smokers (N = 135; 84 menthol smokers) self-reported their chemosensory function and participated in smell (identification task with perceived intensity) and taste (quinine and NaCl intensity on tongue-tip and whole mouth) testing. A taste genetics probe (propylthiouracil (PROP) bitterness) also was assessed. Self-reported and measured chemosensory function were compared with nationally-representative 2013-2014 National Health and Nutrition Examination Survey (NHANES) data generated with similar measures. The taste measures also were compared between smokers and age- and sex-matched non-smokers from a laboratory database. Frequencies of self-reported smell and taste alterations among smokers exceeded NHANES prevalence estimates for non-smokers. The rate of measured smell dysfunction also exceeded NHANES prevalence for hyposmia. Compared to non-smokers, smokers reported elevated tongue-tip and whole mouth intensities from 1 M NaCl, with no significant differences in whole mouth quinine or 0.32 M NaCl. Inconsistent with previous hypotheses, smokers were not more likely to report depressed PROP bitterness than non-smokers. However, as expected, menthol smokers reported greater PROP bitterness than non-menthol smokers. In conclusion, chemosensory alterations were more frequent among chronic smokers, including hyposmia and heightened intensity from NaCl at an oral-irritant concentration. PROP supertasters were most likely to prefer mentholated cigarettes.