An Online Compendium of News & Clinical Science November 20, 2017

Disorders of Odor Perception offers links to the latest science and news about olfactory dysfunction. It is updated frequently. Newest items are at the top of each column.

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Anosmia & Hyposmia

A population-based study in Sweden highlights demographic and genetic factors associated with reduced odor identification ability in 60- to 90-year-olds. Read more.
A large study finds sensory impairments, including smell, are associated with subtle deficits in cognitive function in middle age. Read more.
Large-scale cross-sectional study suggests link between major depressive disorder and olfactory impairment. Read more.
Odor identification scores are reduced in patients with chronic kidney disease and end stage renal disease. Read more.
Olfactory dysfunction is associated with type 1 diabetes, especially in patients with peripheral neuropathy. Read more.
Novel nonsemantic tests based on odor mixtures proposed for evaluation of olfactory sensitivity and resolution. Read more.
Large retrospective case analysis identifies specific elements of work-related head injury that result in smell loss. Read more.
Endoscopic sinus surgery improves odor perception in patients with chronic rhinosinusitis with nasal polyps. Read more.
Decreased olfactory function associated with low levels of plasma tryptophan. Read more.
Community-based studies of older adults indicate markedly higher rates of anosmia in black populations compared to white populations. Read more.
European smell identification test for children is cross-culturally adapted for U.S. children. Read more.
Among patients with amyotrophic lateral sclerosis, olfactory function is significantly worse in those with symptoms of frontotemporal dementia. Read more.
Increased olfactory sensitivity in young women with, and recovering from, anorexia nervosa. Read more.
Three months of nasal CPAP therapy improves smell function in patients with obstructive sleep apnea. Read more.
Longitudinal study reports widespread olfactory dysfunction in patients with multiple sclerosis. Read more.
Different causes of hyposmia linked to specific patterns of loss across tests of olfactory threshold, identification, and discrimination. Read more.
Weekly exercise associated with reduced odds of impaired odor detection in older adults. Read more.
Lack of awareness of smell dysfunction more common in adults with specific age, race, and marital status. Read more.
Odor identification test a useful, inexpensive marker for identifying preclinical Alzheimer's disease. Read more.
Case study of dysguesia and hyposmia as a result of lithium carbonate treatment for cluster headache. Read more.
Olfactory dysfunction more frequent and severe in primary progressive multiple sclerosis than in relapsing-remitting MS. Read more.
Reduced olfactory identification scores associated with biochemical markers of Alzheimer's disease. Read more.
Anterior palatoplasty for snoring improves retronasal olfactory function. Read more.
Laryngopharyngeal reflux raises olfactory thresholds but has no effect on odor identification or discrimination. Read more.
Rhinophototherapy has no effect on olfactory threshold scores in patients with chronic rhinosinusitis without nasal polyps. Read more.
Women on low-dose oral contraceptives have better olfactory performance that those on high-dose versions. Read more.
Odor perception is impaired in laryngopharyngeal reflux disease. Read more.
Post-operative olfactory rehabilitation improves smell and quality of life in patients with total laryngectomy. Read more.
Extended lumbar drainage does not improve odor identification scores in patients with normal pressure hydrocephalus. Read more.
Early odor identification impairment in people with Parkinson's disease-associated MAPT mutations is not reliably smell-specific. Read more.
No lateralized inter-nostril differences in odor sensitivity in multiple sclerosis. Read more.
Questionnaire-based study finds greater olfactory dysfunction in older and more disabled multiple sclerosis patients. Read more.
Heavy and light weight molecules equally effective in smell training therapy for post-viral and post-traumatic olfactory loss. Read more.
Poor odor identification ability linked to increased risk of developing dementia. Read more.
MRI reveals abnormal olfactory bulb volume correlated with smell dysfunction in patients with Bardet-Biedl syndrome. Read more.
Large-scale study in Korea links olfactory dysfunction to reduced intake of dietary fat. Read more.
No difference found between two methods of endonasal steroid application for chronic rhinosinusitis. Read more.
Normal smell and normal cognition at initial diagnosis predict benign 10-year cognitive course in Parkinson's disease. Read more.
Migraineurs with interictal olfactory hypersensitivity are less likely to report osmophobia and odor-triggered headaches. Read more.
Allergic and nonallergic rhinitis not associated with reduced olfactory function in children. Read more.
Opacification of the olfactory cleft correlates with degree of smell impairment in patients with chronic rhinosinusitis. Read more.
Caffeine has no short-term effect on odor perception in patients with hyposmia. Read more.
Osmophobia associated with greater olfactory dysfunction in migraine patients. Read more.
Use of intranasal sodium hyaluronate as adjuvent in treatment of acute rhinosinusitis improves some measures of olfactory function. Read more.
Large study of older U.S. adults links social life to olfactory function and finds a sex difference. Read more.
Loneliness and depression associated with olfactory dysfunction in older adults. Read more.
Case study of snakebite by Pseudechis australis resulting in anosmia and olfactory bulb atrophy. Read more.
Hyposmia and anosmia alter some but not all disgust-related personality traits in men. Read more.
Treatment of hypothyroidism is correlated positively with improvement of smell and taste function. Read more.
Possible association between olfactory function and erectile dysfunction in men. Read more.
Severity of olfactory impairment correlates with CT opacification of sinuses and olfactory cleft in chronic rhinosinusitis. Read more.
One-time application of sodium citrate solution to olfactory cleft improves smell function selectively in post-viral hyposmia. Read more.
Taste and smell alterations confirmed as important symptoms and quality of life predictors in patients treated for head and neck cancer. Read more.
Increase in visceral fat in women associated with reduced performance on multiple measures of odor perception. Read more.
Topical application of corticosteroids maintains improvement in olfactory performance following course of oral steroids. Read more.
Possible increase in self-reported olfactory impairment among workers exposed to phenolic resins. Read more.
Moderate to severe olfactory impairment can result in poor diet quality in people 60 and older. Read more.
Use of bilateral spreader grafts results in improved olfactory function following septorhinoplasty. Read more.
Long-term recovery of smell function is observed in cases of pediatric traumatic brain injury but less often in severe cases. Read more.
Nasal polyps with comorbid allergy linked to poor olfactory-specific quality of life, but may improve with endoscopic sinus surgery. Read more.
Intensity-modulated radiotherapy for nasopharyngeal cancer may result in mild impairment of olfactory function. Read more.
Olfactory bulb volume is lower in patients with multiple sclerosis and associated with higher depression scores. Read more.
Prospective longitudinal study of pediatric traumatic brain injury relates olfactory dysfunction to severity of injury. Read more.
Processing of odor perception is maintained in a majority of vegetative and minimally conscious patients. Read more.
Widely-used odor identification test modified for use in Egypt and Arabic language regions. Read more.
Olfactory ability is associated with less anhedonia but more social fear in patients with schizophrenia. Read more.
Previous occupational exposure to manganese has no effect on olfactory function later in life. Read more.
An olfactory test based on sniff magnitude response correlates well with an established multitest battery. Read more.
Chemotherapy for head and neck malignancies is associated with transient reduction in odor perception. Read more.
Olfactory ability is associated with cognitive status but not nutritional status in geriatric patients. Read more.
Standardized testing finds improved smell function following septorhinoplasty surgery but no evidence in patients of subjective improvement. Read more.
Evidence of impaired odor associations but not identification or discrimination in patients with frontotemporal dementia. Read more.
Cultural modification of existing smell test validated for use in Denmark. Read more.
Clustering of patients with olfactory dysfunction by machine-learning pattern identification finds no clear separation between etiologies. Read more.
Sensory latency to intravenous odor injection predicts recovery of olfactory function following sinus surgery. Read more.
Olfactory function impaired in patients with gastro-esophageal reflux disease. Read more.

Parosmia, Dysosmia, Cacosmia & Phantosmia

Ictal fear associated with olfactory auras in patients with focal epilepsy. Read more.
Phantosmia and somatosensory disturbances in patient with long history of migrainous headaches. Read more.
Olfactory hallucinations occur in almost half of patients with transient epileptic amnesia. Read more.
Two case reports of phantosmia in migraine with and without headache. Read more.
Case study of dysosmia and dysgeusia associated with midodrine taken for orthostatic hypotension. Read more.
Case study of olfactory hallucination in Parkinson's disease successfully treated with donepezil. Read more.
Hypnotic suggestion induces altered odor perception in highly hypnotizable individuals. Read more.
Olfactory changes confirmed as frequent feature of aura preceding migraine. Read more.
ICD-11 working group explains grouping of olfactory reference disorder with obsessive-complusive and related disorders on basis of repetitive unwanted thoughts. Read more.
Internet-based study outlines clinical features of olfactory reference syndrome. Read more.
Olfactory cortex gray matter volume reduced in combat veterans with post traumatic stress disorder and negatively correlated with odor-related trauma memories. Read more.
Central versus peripheral phantosmia and the efficacy of surgical intervention reviewed in five cases. Read more.
Case study from Massachusetts General Hospital of a 32-year-old man with olfactory hallucinations and paresthesias. Read more.
Case report of delayed dysosmia and dysguesia after thalamic infarction. Read more.
Case report suggests usefulness of cognitive-behavioral therapy for psychosis in treatment of olfactory hallucinations. Read more.
Olfactory hallucinations as warning sign in patient with bipolar disorder. Read more.
Case study: olfactory hallucinations as primary symptom for ischemic stroke in the right posterior insula. Read more.
High prevalence of osmophobia in migraine patients makes it a useful tool in primary care diagnosis of migraine. Read more.
Osmophobia more often associated with cutaneous allodynia in chronic rather than episodic migraine. Read more.
Case study of PTSD patient with olfactory hallucinations finds enhanced connectivity in olfactory cortex. Read more.
Olfactory hallucinations found in 3.9% of young migraineurs; typically follow shortly on onset of headache and last 15 to 50 minutes. Read more.
Osmophobia is a significant risk factor for suicidality in migraine patients. Read more.
Case study of patient with abdominal pain, arterial hypertension, and smell disturbances due to adrenocortical adenoma. Read more.
Survey of 269 patients with chemosensory disorders finds dysosmia more frequent in patients taking more than four medications daily. Read more.
Case report of 37-year-old woman with delusions of bad breath discussed with respect to differential diagnoses. Read more.
"Bad smell", nausea and dizziness as symptoms of cerebral aneurysm in a 54-year-old woman. Read more.
Epilepsy Phenome/Genome Project finds no sex difference in olfactory symptoms related to epileptic seizures. Read more.
The use of valproate to manage idiopathic olfactory hallucinations. Read more.
Case study of olfactory hallucinations in a 53-year-old woman with post-traumatic stress disorder. Read more.
Case study finds parosmia in a middle-aged woman associated with vitamin B12 deficiency. Read more.
Self-selected sample of 496 Britains suffering olfactory dysfunction finds parosmia experienced by 19% and phantosmia by 24%. Read more.
Two case studies suggest that olfactory reference syndrome responds to treatment with antipsychotic and SSRI medications. Read more.
Case study of olfactory hallucinations serving as early warning sign in patient with bipolar disorder. Read more.
Report of Charles Bonnet syndrome with olfactory hallucinations. Read more.
Parosmia and phantosmia are enhanced in patients with severe depression. Read more.
Significant prevalence of olfactory hallucinations in Parkinson's disease. Read more.
No long-term benefit to topical cocainization as a treatment for phantosmia. Read more.
Patient complaining of bad body odor suffering from olfactory delusional syndrome rather than phantosmia. Read more.
Odor source localization less accurate in schizophrenic patients with olfactory hallucinations. Read more.
Case study of cacosmia associated with fungal dacryocystitis. Read more.
Halitosis-like phantosmia experienced by two young patients undergoing radiation therapy for brain tumors. Read more.
Case report of unilateral cacosmia associated with maxillary sinus fungal infection. Read more.
Case report of complex olfactory hallucinations during a migraine attack in a 17-year-old patient. Read more.
Despite expense, MRI imaging is cost-effective in the workup of idiopathic dysosmia. Read more.
Schizophrenic patients have altered hedonic responses to the smell of amyl acetate. Read more.
Changes in odor perception during major depressive episode persist after clinical improvement of depression. Read more.
Osmophobia is common in Taiwanese migaineurs and linked to higher anxiety and depression scores. Read more.
Olfactory reference syndrome in a patient with Parkinson's disease. Read more.
A study links olfactory hallucinations in schizophrenia to specific neuropsychological impairments. Read more.
A case report of Olfactory Reference Syndrome discusses proposed changes to the DSM-V classification. Read more.
Olfactory hallucinations may be a significant non-motor symptom in Parkinson's disease. Read more.
Schizophrenic patients with olfactory hallucinations more likely to have olfactory habituation deficits and past episodes of brief unconsciousness. Read more.
Case report of subacute combined degeneration of the spinal cord and a novel dysosmia. Read more.
An unusual case of migraine headache associated with olfactory hallucinations in a patient with post-traumatic anosmia. Read more.
Activation of subdural electrodes implanted near the olfactory bulb in epileptic children produce olfactory hallucinations. Read more.
A case report of long lasting phantosmia that disappeared under anti-depressive treatment with venlafaxine. Read more.
Case report of headaches in a migraine patient induced by a Valsalva manoeuvre she used to relieve persistent cacosmia. Read more.
Large Chinese study characterizes olfactory and trigeminal event-related potentials in hyposmic and anosmic patients. Read more.
Olfactory hallucinations in headache typically last 5 to 60 minutes, occur shortly before or with the onset of head pain, and consist of a highly specific unpleasant odor. Read more.
A review of the current clinical understanding of olfactory distortions and how to evaluate them. Read more.
A case report from Ceylon of a soldier in his early thirties diagnosed with Olfactory Reference Syndrome, on the basis of an imagined smell of urine in the absence of actual urinary incontinence. Read more.
Australian psychologist R.J. Stevenson examines the evidence for olfactory illusions and the reasons they may escape awareness. Read more.
The body locations that most frequently preoccupy patients with Olfactory Reference Syndrome are mouth (75%), armpits (60%) and genitals (35%). Read more.
A review of all 84 case studies of Olfactory Reference Syndrome published since 1891 reveals that a majority of patients are male with an age of onset <20 years. Read more.
Brain areas involved in odor quality discrimination and odor memory are reduced in size in parosmic patients. Read more.

News & Reviews

A systematic literature review of olfaction in autism spectrum disorders suggests smell dysfunction may be present in these disorders, and that smell testing might have a role in their clinical assessment. Read more.
A review of 50 articles published in the past 20 years about sinonasal status in aging populations finds that immunosenescence, frequency of rhinorrhea, and perception of nasal obstruction all increase with age, a condition the authors call presbynasalis. Read more.

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A systematic review and meta-analysis of published studies on chronic rhinosinusitis finds that a significant percentage of patients experiences olfactory dysfunction, with test scores that fall into the dysosmic range. Read more.
Case series review confirms recovery from olfactory dysfunction more likely in patients with respiratory tract infection etiology than those with head trauma, and that systemic steroid treatment may be superior to topical applications. Read more.
Researchers theorize that depression could lead via inattention to reduced olfactory bulb size and activity, and that the bulb may be a useful marker for enhanced vulnerability to depression. Read more.
Researcher suggests that smell dysfunction in neurodegenerative diseases such as Alzheimer's and Parkinson's may have in common damage to forebrain neurotransmitter and neuromodulator circuits involving cholinergic transmission. Read more.
An extended version of the clincal update presented at the 2016 AChemS meeting reviews anosmia from the perspective of patients, diagnosticians, and scientific researchers. Read more.
Review of smell and taste in autism spectrum disorders finds 14 studies showing some differences in odor identification but not detection threshold or pleasantness and intensity perception. Read more.

A paper in the American Journal of Rhinology and Allergy reviews differential diagnosis, workup, and current treatment strategies for anosmia and smell disorders. Read more.
A review of 229 studies on olfactory dysfunction associated with radiotherapy for head and neck cancer confirms that odor detection, identification and discrimination are impaired following treatment. Read more.
The current state of the art in olfactory exploration is reviewed from the point of view of ENT specialists. Read more.
A scoping review of the literature on smell function in multiple sclerosis suggests that impairment is significant and may range from 20% to 45% in the MS population while mechanisms and clinical relevance remain poorly understood. Read more.
Review of papers from 1950 to 2015 on ambient air pollution and human olfaction finds that exposure to polluted air may impact the sense of smell and that future studies should use direct measures of exposure rather than proxy variables. Read more.
Review finds need for better awareness and measurement of olfactory function by physicians when undertaking endoscopic skull base surgery. Read more.
Statistical analysis of smell test results from 10,714 people reveals distinct subpathologies and suggests hyposmia may be a separate diagnostic entity from anosmia and normosmia. Read more.
British academic and anosmic John Sutherland's new book Orwell’s Nose: A Pathological Biography highlights the importance of smell as depicted in the literary works of George Orwell, James Joyce, Jonathan Franzen and others. Read more.
A mini-review examines the causes, prevalence, and consequences of olfactory impairment in aging. Read more.
Comprehensive overview of olfactory neuropathology in incipient Alzheimer's disease with suggested strategies for enhancing olfactory function and ameliorating cognitive decline. Read more.
Odor sensitivity predicts size of a person's social network. Read more.
Literature review examines fifteen patient-reported outcome measures for chronic rhinosinusitis, identifies best measures. Read more.
A meta review of 20 years worth of studies on prevention and management of taste and smell alterations in cancer patients concludes that no intervention has proven effective. Read more.
Bringing the link between Alzheimer's disease and smell into sharper focus: a review of AD pathology in olfactory system interneurons. Read more.
A chapter by Richard Doty in the new Handbook of Clinical Neurology covers the neurotoxic consequences on smell of exposure to solvents, metals, and particulate matter. Read more.
In nine studies of endoscopic sinus surgery, some show improvement in olfactory performance with resection (versus preservation) of middle turbinate. Read more.
A review of 36 studies on smell in allergic rhinitis finds likelihood of olfactory dysfunction increases with duration of disorder, reaching frequencies of 20% to 40%, and only limited evidence that treatments improve function. Read more.

In an essay at Mosaic Science, Emma Young describes how life has changed for Nick Johnson following a traumatic brain injury that left him anosmic. Read more.


Meta-analysis of controlled clinical trials of chronic rhinosinusitis with nasal polyposis finds treatment with oral steroids significantly improves objective and subjective measures of olfaction. Read more.
Neuromodulation of olfactory and gustatory processing is produced by a variety of neurotransmitters and neuropeptides, as described in a new review. Read more.
A literature review finds high prevalence of smell and taste alterations in patients undergoing palliative care. Read more.
A German review article for ENTs describes the state of the art in the diagnosis of olfactory disorders. Read more.
A selective review of the literature recommends further research into the utility of smell testing in routine clinical practice as a diagnostic tool for Alzheimer's disease. Read more.
Case review of 100 consecutive patients finds MRI imaging adds little value to patient history and clinical examination findings. Read more.
Human clinical data and animal models suggest a link between olfactory dysfunction and depression. Read more.
Olfaction is among the sensory modalities that display altered processing in migraine. Read more.
Review of the literature suggests that olfactory dysfunction may be useful in differential diagnosis of two common conditions in the elderly: Alzheimer's disease and depression. Read more.
A literature review considers how to use olfactory tests that detect incipient Alzheimer's dementia in clinical trials and screening programs. Read more.
A new review highlights the functional significance of social chemosignals in human reproduction and survival. Read more.
Impaired olfaction is a characteristic feature of Parkinson's disease. A new review summarizes this aspect of PD and the use of smell tests for early and differential diagnosis. Read more.
A cross-cultural comparison of Europeans, Cook Islanders and the Tsimane' of Bolivia finds higher olfactory acuity in the second group, a modern society living amid less air pollution. Read more.
Review of legal cases in the Westlaw database suggests that median settlements and awards for olfactory dysfunction resulting from physician negligence are $300,000 and $412,500 respectively. Read more.
A review of olfactory dysfunction in dementia examines current research and compilation of olfactory assessment tools. Read more.
Systematic literature review finds lack of standardization in quantitative assessment of children's sense of smell. Read more.
Differences in cannabinoid receptor expression in olfactory bulb may account for different sensory effects of cannabis in mice and humans. Read more.
Transient receptor potential (TRP) channels could play a important functional roles in mammalian olfaction. Read more.
A review of olfactory bulb involvement in neurodegenerative diseases, with analysis of large autopsy study of olfactory tract and bulb pathology. Read more.
Literature review finds clear and consistent correlation between general olfactory function and olfactory bulb volume. Read more.
Anatomical features of the anthropoid nose are vestiges of previously functional structures; the vomeronasal organ is absent in adult humans but has a role in olfactory neurogenesis. Read more.
Olfactory event-related potentials now have been recorded successfully from infants between 23 and 41 days old. Read more.
The role of anti-inflammatory therapy and controlled odor exposure in the management of gradual onset smell loss. Read more.
Meta-analysis suggests that olfactory deficits are a useful marker for schizophrenia risk status. Read more.
A review of the anatomy and cellular constituents of the human olfactory mucosa. Read more.
The few studies available suggest that anosmia and olfactory dysfunction are dose-response outcomes of pediatric traumatic brain injury. Read more.
A review of the literature considers how smell impairment impacts quality of life. Read more.
A review of hyposmia in Parkinson's disease and its role as a potential biomarker. Read more.
French review of surgical treatment for nasal polyposis finds improvement in olfactory function. Read more.
How variation in olfactory receptor genes contributes to individual differences in odor perception. Read more.
A review of olfactory deficits and other features of different hypogonadotropic hypogonadal syndromes. Read more.
A review of olfactory neuropathology in Alzheimer's disease. Read more.
Interdisciplinary team speculates about olfactory measures to diagnose and treat infant malnutrition. Read more.
A smell and taste clinic reviews findings from 5,183 patients examined over a 40-year span. Read more.
A review of Machado-Joseph disease notes olfactory dysfunction as one of its nonmotor, extracerebellar features. Read more.
A first-person account of congenital anosmia by a philosopher is included in a special smell issue of The Anatomical Record. Read more.
Humans can discriminate as many as one trillion odors, far more than previously thought. Read more.
A comprehensive review suggests links between smell function and autoimmune disease. Read more.
A systematic review of chemosensation in myasthenia gravis recommends olfactory testing in this disorder. Read more.
A literature review places olfactory dysfunction among the non-cognitive symptoms of Alzheimer's disease. Read more.

Disorders of Odor Perception is updated frequently. Items are entered chronologically with newest items at the top of each column.

Disorders of Odor Perception offers links to the latest science and news about olfactory dysfunction. It does not endorse the material on the linked sites, nor does it offer medical advice. For medical advice about disorders of smell, consult your physician.

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