An Online Compendium of News & Clinical Science January 16, 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

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.
Performance of European Test of Olfactory Capabilities in a clinical setting. Read more.
Odor perception improves in morbidly obese patients following laparoscopic sleeve gastrectomy. Read more.
Variation in olfactory identification patterns in Parkinson's disease patients from different countries. Read more.
Olfactory loss after traumatic brain injury linked to length of amnesia not Glasgow Coma Scale score. Read more.
German researchers develop and validate a Food-Associated Olfactory Test. Read more.
Olfactory training in patients with long-term smell loss alters regional functional connectivity. Read more.
fMRI reveals altered brain connectivity in post-URI anosmia. Read more.
Reduced olfactory function in adults with primary hypothyroidism. Read more.
Links between neuropsychological performance and odor identification scores following traumatic brain injury. Read more.
Comprehensive evaluation of olfaction in Down syndrome reveals significant impairment. Read more.
Rhinitis-induced anosmia responsible for disappearance of odor-triggered migraine attacks. Read more.
Brain fMRI odor responses reveal regional attempts at compensation in hyposmic patients. Read more.
Benefits seen after 16- and 56-weeks of olfactory training in patients with post-infectious smell loss. Read more.
Smell deficits reversed in subclinical hypothyroidism after treatment with levothyroxine. Read more.
Validation of Portugeuse version of widely used smell test. Read more.
Korean population study finds olfactory deficits associated with metabolic syndrome in women but not men. Read more.
Physical features of surgery for unruptured aneurysm predict resulting post-op olfactory dysfuction. Read more.
Reduced odor identification performance in euthymic bipolar patients. Read more.
Pilot fMRI study links childhood manganese exposure to reductions in odor sensitivity, olfactory bulb volume, and limbic system BOLD response. Read more.
Nostril asymmetry in odor perception distinguishes patients with mild cognitive impairment from healthy controls. Read more.
Small subset of odor identification test items separates Alzheimer disease patients from healthy controls. Read more.
Obese patients with impaired smell and taste show improvement following bariatric surgery. Read more.
Opacification of olfactory cleft linked to reduced olfactory performance. Read more.
Odor identification deficits higher in people homozygous for Alzheimer's disease-related ApoE4 allele. Read more.
No correlation between olfactory bulb volume and mild cognitive impairment or Alzheimer's diease. Read more.
Study of chronic pain patients links extended use of analgesics with reduced olfactory and trigeminal function. Read more.
2012 update of U.S. NHANES population survey describes age trends in and risk factors for olfactory dysfunction. Read more.
Researchers develop Turkish-specific variant of an odor identification test. Read more.
Turkish study finds smell and taste dysfunction in patients with myasthenia gravis. Read more.
Lower olfactory performance in stroke patients one year after event. Read more.
Subclinical atherosclerosis as a risk factor for development of olfactory impairment. Read more.
Case study of a teenaged girl with isolated anosmia. Read more.
A case study of reflex epilepsy triggered by smell. Read more.
Nasal "cycle" in conjunction with unilateral smell impairment may present as rapidly fluctuating anosmia. Read more.
Impaired odor identification ability in patients with temperal lobe epilepsy. Read more.
Case study of SCN9A gene mutation linked to anosmia and congenital insensitivity to pain. Read more.
Smell training may improve odor perception in Parkinson's disease patients. Read more.
Odor identification scores correlate with lesion location and cognitive measures in traumatic brain injury patients. Read more.
Large, multicenter study finds odor identification scores to be quick and accurate diagnostic tool for Parkinson's disease. Read more.
Multiple odors are effective in assessing smell after functional endoscopic sinus surgery for nasal polyps. Read more.
Improvement in odor perception after endoscopic removal of nasal polyps. Read more.
Odor perception deficits found in patients with alcohol dependence and Korsakoff Syndrome. Read more.
Mayo Clinic Study of Aging links reduction in odor identification to amnestic mild cognitive impairment and progression to Alzheimer's dementia. Read more.
Chemotherapy is associated with olfactory impairment, with patients >50 years old more susceptible than younger patients. Read more.
Smell and taste impairment not significantly related to eating pleasure and appetite in older, independently living Italian adults. Read more.
Large-scale population study in South Korea links olfactory dysfunction to elevated risk of depressed mood and suicidal ideation. Read more.
Odor identification scores trend lower with lead exposure in elderly men. Read more.
Children with autism spectrum disorder fail to modulate sniff response to pleasant versus unpleasant odors. Read more.
Patients with impaired odor perception are more likely to be overweight or obese than controls. Read more.
Age-related macular degeneration is associated with impaired odor perception. Read more.
Volume of olfactory bulbs/tracts based on MRI, combined with olfactory measures, can distinguish Parkinson's disease from related disorders. Read more.
State and trait anxiety (but not smoking) linked to reduced olfactory ability. Read more.
Self-assessment of olfactory loss correlates with actual performance only at the level of total anosmia. Read more.
Parkinson's disease patients who smoke show less olfactory dysfunction than patients who never smoked or who no longer smoke. Read more.
Genome-wide analysis of older adults suggests SNPs at tau protein locus may link olfactory dysfunction to neurodegenerative diseases. Read more.
Mutation in TENMI gene linked to congenital general anosmia. Read more.
Large-scale study in Italy suggests sense of smell does not decrease linearly with age but forms 'juvenile,' 'mature,' and 'elder' phenotypes. Read more.
Olfactory performance scores can help discriminate Alzheimer's disease from dementia with Lewy bodies in patients with mild cognitive impairment. Read more.
Changes in olfactory sensitivity with age may be odor-specific. Read more.
Algorithm predicts extent of post-traumatic olfactory loss based on pattern of brain lesions. Read more.
Olfactory dysfunction in Parkinson's disease is associated with faster disease progression. Read more.
Hormone replacement therapy in postmenopausal women positively influences a limited number of olfactory and cognitive measures. Read more.
Smell dysfunction in first-degree relatives of patients with cleft lip or palate linked to morphology of upper nasal region. Read more.
Olfactory impairment reduces physical but not mental quality of life measures, with combined sensory impairments worsening the effect of a single-sense deficit. Read more.
Only three smells are necessary for an odor identification test with sufficient sensitivity and specificity. Read more.
Neuroticism scores are higher in patients with olfactory dysfunction. Read more.
Lingering post-smell activation in orbitofrontal cortex observed in patients with multiple chemical sensitivity. Read more.
Consultation with ENT physician improves quality of life and olfactory measures in chronic rhinosinusitis patients. Read more.
Reduced olfactory function in obese women linked to higher levels of circulating endocannabinoids. Read more.
Comparison of two smell tests finds performance difference when used with children five to six years of age. Read more.
Radiation treatment for nasopharyngeal cancer associated with impaired smell and taste function. Read more.
Study suggests normosmic Parkinson's disease patients are a unique clinical phenotype with more benign course. Read more.
Olfactory bulb volume in Parkinson's disease not associated with disease severity or smell function. Read more.
Olfactory bulb volume increases and odor sensitivity improves after functional endoscopic sinus surgery for nasal polyps. Read more.
Five-year followup confirms African-Americans more likely than other groups to experience initial decline in olfactory function. Read more.
Atrophy in primary olfactory cortex and hippocampus correlates with smell loss in mild cognitive impairment and Alzheimer's dieseas. Read more.
Manganese exposure in teenagers linked to reduced odor perception and to changes in brain response and morphology. Read more.
New self-administered, computerized olfactory threshold test validated on patients with anosmia and hyposmia. Read more.
New test of odor identification and intensity validated for Taiwanese population. Read more.
Odor identification test shows correlations with age and Alzheimer's disease in Japanese population. Read more.
Plasma oxytocin levels may predict odor identification ability and negativity of odor response in patients with schizophrenia. Read more.
MRI confirms reduced/absent olfactory bulbs and hypoplastic olfactory sulci in congenital anosmics. Read more.
MRI study finds age, laterality, and task-specific effects of smell loss on olfactory bulb volume and olfactory sulcus depth. Read more.
Rapid maxillary expansion improves olfactory sensitivity in children. Read more.
Age-related trends in odor perception confirmed in large, cumulative ad hoc dataset. Read more.
Odor identification scores fail to predict transition from ultra-high risk status to schizophrenia but may predict poor functional outcome. Read more.
Study compares MRI results with chemosensory event-related potentials in patients with post-traumatic anosmia. Read more.
No specific histomorphological changes found in peripheral olfactory epithelium of schizophrenic patients relative to controls. Read more.
Olfactory event-related potentials are absent or reduced in young patients with multiple sclerosis. Read more.
Extended 32-item version of a commercial odor identification test shows high validity and test-retest reliability. Read more.

Parosmia, Dysosmia, Cacosmia & Phantosmia

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 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.

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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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