Olfactory Function and Olfactory Disorders. / Riechen und Riechstörungen.

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.

Factors associated with relevant olfactory recovery after olfactory training: a retrospective study including 601 participants.

BACKGROUND: Olfactory training (OT) represents a therapeutic option for multiple etiologies of olfactory dysfunction (OD) that also benefits normosmic subjects. In this retrospective study, we report the effectiveness of OT and factors associated with relevant changes in olfactory function (OF) in large groups of normosmic participants and patients with OD, including a control group that performed no training. METHODS: This was a retrospective pooled analysis including 2 treatment cohorts of 8 previously published studies. Adult partici- pants that either presented with the major complaint of quantitative OD or normosmic volunteers were recruited at various ENT clinics and received OT or no training. The outcome was based on changes in objective olfactory test scores after OT. RESULTS: A total of 601 patients with OD or normosmic subjects were included. OT was more effective compared to no training. No interaction was found between OT and OF. In multivariate analysis, higher baseline OF (adjusted odds ratio, aOR, 0.93) and posttraumatic (aOR, 0.29) or idiopathic OD (aOR, 0.18) compared to postinfectious causes were significantly associated with lower odds of relevant improvements in patients with OD receiving OT. Subgroup analysis of normosmic participants receiving OT further revealed a significant association of age and baseline olfactory function with improvements of overall OF. CONCLUSIONS: This study demonstrated that OT was more effective than no training in patients with various causes of OD. Additi- onally, baseline olfactory performance and etiology of OD were identified as important factors associated with relevant improve- ments after OT.

Updated Sniffin' Sticks normative data based on an extended sample of 9139 subjects.

PURPOSE: To provide up-to-date and detailed normative data based on a large-scale sample, increasing diagnostic validity by reference to narrow age groups as previous normative values were based upon smaller sample sizes-especially in the group of older subjects. METHOD: Data were obtained from 9139 healthy subjects (4928 females aged 5-96 years and 4211 males aged 5-91 years). The standard "Sniffin' Sticks" test was applied, comprising threshold (T), discrimination (D) and identification (I) subtests, and yielding a TDI sum score. RESULTS: Hyposmia was established at a TDI score of less than 30.75. Age-related changes were found in each domain, most pronounced for thresholds. Individuals aged 20-30 years performed best, whereas children below the age of 10 and adults above the age of 71 scored only half as well. Sex-related differences were in favor of women. CONCLUSIONS: Data provide guidance for assessing individual olfactory performance in relation to specific age groups. Significant gender and age effects were observed, with a most pronounced increase of olfactory test scores between age 5 through 20 years and a dramatic decrease at the age of 60 through 71 years.

[DreKiP - an outpatient treatment program for children and adolescents with headache]. / DreKiP ­ ein ambulantes Therapieprogramm für Kinder und Jugendliche mit Kopfschmerzen.

Headaches are a frequent health problem among children and adolescents. The ocurrence of headaches and the resulting impairments in the quality of life and activities of daily living are modulated by biopsychosocial interactions, which necessitate a complex treatment program. The Dresden Childrens Headache Program (DreKiP) is a multidisciplinary therapy program consisting of eight modules for children and adolescents: education, stress relief, relaxation techniques, physical fitness, climbing therapy, art therapy and sensory training. In addition, there are six modules containing parallel workshops for parents. This outpatient program lasts 2-3 months and is performed parallel to the daily and school routine. Therapy groups consist of 6-8 patients in each age group. In total patients receive 15 h and the parents 7 h of therapy. Concomitant with the program, headache-associated data, such as headache frequency, medication use and school absence are documented. So far 32 children and adolescents in groups of 11, 14-15, 14-16, 17 and 17-18 years old completed the program. Of the 32 patients 19 presented with migraine and tension type headache, 6/32 with migraine and 7/32 with tension type headache only. The median number of headache days was 15 per month and 4 official school absence days per month. Preliminary results 6 months after the end of the therapy program showed reduced frequency of headaches in three quarters of our patients. The headache frequency was reduced from an initial median of 15 days per month to a median of 8 days per month after the program. The multidisciplinary program DreKiP improves the use of therapeutic means in children and adolescents with primary headaches. Children and adolescents with headache-related impairment in activities of daily life in school and leisure times constitute the target group of this therapy.

Olfactory function in patients with hyposmia compared to healthy subjects - An fMRI study.

BACKGROUND: Individuals with hyposmia, or the partial loss of smell, represent a large sector (15 %) of the population that is likely to grow with the current aging population; however, our understanding to how hyposmics centrally process odors is still not clear. One popular non-invasive tool for in vivo imaging of biological activity among human brains has been function magnetic resonance imaging (fMRI) which uses blood-oxygenation level dependent (BOLD) signal as an indirect measurement. Therefore, the aim of this study was to understand differences in olfaction processing between patients with hyposmia and healthy controls using functional magnetic resonance imaging (fMRI). METHODOLOGY: Eleven hyposmic and 12 healthy, normosmic subjects were exposed to two different food-related odors (coffee and peach) during a block-designed fMRI session. Additionally, odor perception qualities were rated for each odor throughout the scanning session. RESULTS: The activations of the normosmic group were localized in typical olfactory areas (insula, orbitofrontal cortex [OFC], limbic system and amygdala). The hyposmic group showed similar regions of activation (insula, OFC, limbic system), however, less activation was found in the amygdala, left anterior cingulate and right OFC, but higher activation was shown in the right parahippocampal and both the left and right posterior cingulate gyrus which are assumed to play an important role in the processing and remembrance of memories. CONCLUSIONS: These results indicate similar central olfactory processing among groups, yet subjects with partial loss may attempt to compensate smell impairment with odor memory or higher motivation to smell.

Source localization of event-related brain activity elicited by food and nonfood odors.

Tastes and odors influence the perception of a meal. Especially food aromas can act as potent signals to modulate our eating behavior with strong dependency on the reward produced by food. In this investigation we aimed to study the electrophysiological response to food- and non-food-related odors in healthy volunteers. Analyses revealed specific scalp potential maps for the two conditions; in particular the source of the map in the "food" condition seemed to be associated with the processing of rewards; the specific map in the "non-food" condition reflects odor characteristics excluding the reward.

Are small olfactory bulbs a risk for olfactory loss following an upper respiratory tract infection?

Considering the correlation between olfactory function and size of the human olfactory bulb (OB), it may be that OB volume is representative of the average number of functional olfactory receptor neurons in the nose. We observed a woman (64-year-old) with a 3-week history of hyposmia following an upper respiratory tract infection. Interestingly, both OB volumes were below the tenth percentile of the general population which seems to be difficult to explain by rapid, adaptive changes in the OB volume. It is hypothesized that small OBs may be a risk factor for acquiring olfactory loss.

Changes of olfactory abilities in relation to age: odor identification in more than 1400 people aged 4 to 80 years.

The currently presented large dataset (n = 1,422) consists of results that have been assembled over the last 8 years at science fairs using the 16-item odor identification part of the "Sniffin' Sticks". In this context, the focus was on olfactory function in children; in addition before testing, we asked participants to rate their olfactory abilities and the patency of the nasal airways. We reinvestigated some simple questions, e.g., differences in olfactory odor identification abilities in relation to age, sex, self-ratings of olfactory function and nasal patency. Three major results evolved: first, consistent with previously published reports, we found that identification scores of the youngest and the oldest participants were lower than the scores obtained by people aged 20-60. Second, we observed an age-related increase in the olfactory abilities of children. Moreover, the self-assessed olfactory abilities were related to actual performance in the smell test, but only in adults, and self-assessed nasal patency was not related to the "Sniffin' Sticks" identification score.

A brain-lesion pattern based algorithm for the diagnosis of posttraumatic olfactory loss.

BACKGROUND: Brain areas processing olfactory information exhibit functionally relevant morphological dynamics. This suggests the exploitation of anatomical information in the diagnosis of an olfactory dysfunction. Following previous identifications of olfactory eloquent areas such as the olfactory bulbs and tracts, we focused at a brain-morphology based algorithm for establishing the diagnosis of olfactory loss following brain injury. METHODOLOGY: Forty-one patients with a history of head trauma dated back 40 ± 39 months, and additional 23 patients without head trauma, were assessed for damages in 11 olfaction-relevant brain areas using magnetic resonance imaging (MRI). Olfactory function was derived from the use of a standardized, reliable and validated olfactory test. An olfactory diagnostic algorithm was derived following classification and regression tree analysis of the brain lesion pattern. RESULTS: Subjects were assigned to olfactory diagnoses of anosmia, hyposmia or normosmia. These diagnoses were predictable at an accuracy of 62.3 % from the degree of damage in the olfactory bulb and in the left temporal lobe pole. The main diagnosis algorithm addressed the presence of anosmia, which could be predicted from the degree of damage in these brain areas at an accuracy of 81.3 %. CONCLUSIONS: We independently reproduced previously identified brain regions in which morphological damage is associated with olfactory loss. Based on this reproduction, an algorithm was developed for the diagnosis of anosmia from central-nervous damage. Thus, we introduce a morphological component to the olfactory diagnosis that specifically addresses clinical cases of olfactory loss following head trauma.

[Olfactory disorders and their therapy]. / Riechstörungen und ihre Therapie.

Among the main causes of olfactory disorders are chronic rhinosinusitis, head trauma, acute infections of the upper respiratory tract and neurodegenerative diseases. Olfactory disorders can impose major restrictions on our lives. Although there are numerous approaches for the therapy of olfactory disorders, double-blind comparison studies are needed to distinguish between the effects of these therapies and spontaneous remission of olfactory disorders. The most significant aspects of treatments seem to be anti-inflammatory measures and the regenerative capabilities of the olfactory neuroepithelium.

Characteristics of taste disorders.

Aim of this retrospective study was to obtain information about the frequency of taste disorders, their most frequent causes, and typical symptoms. A total of 491 out of 4,680 patients (presenting for the first time between 1998 and 2011) exhibited taste disorders (10.5 %). All patients underwent a thorough physical otorhinolaryngological examination including detailed assessment of smell and taste functions. The three most frequent causes of disorders were idiopathic (34 %), posttraumatic (24 %), and postoperative (15 %). Patients with idiopathic and postoperative taste disorders complained mainly about hypogeusia and parageusia; in comparison, patients with posttraumatic taste disorders exhibited a relatively higher degree of partial, local, or complete ageusia. Among patients with phantogeusia and parageusia, 38 % reported salty, and 22 % mixed sensations like bitter-salty or sour-sweet. In approximately 1/3 of this group of patients the cause of dysgeusia is unknown. Twenty-one percent of the patients complained of qualitative rather than quantitative taste problems.

[Olfactory dysfunction in neurodegenerative disorders]. / Riechstörungen bei neurodegenerativen Erkrankungen.

Impairment of olfaction is a characteristic feature of many neurodegenerative diseases. This review summarizes the available information about olfactory function in distinct neurodegenerative conditions and indicates the advantageous use of olfactory testing in the diagnosis of Parkinson's disease and Alzheimer's dementia.

[Olfactory dysfunction in Parkinson's disease: its role as a new cardinal sign in early and differential diagnosis]. / Riechstörungen bei Morbus Parkinson : Ein neues Kardinalsymptom mit Relevanz für die Früh- und Differenzialdiagnose?

Olfactory dysfunction is a prominent symptom in Parkinson's disease (PD) and found in about 70-100% of patients. In earlier studies significant loss of olfactory function seemed to be unrelated to disease duration, did not correlate with motor function, and was uninfluenced by antiparkinsonian medication. We suggest that the increase of dopaminergic cells in the olfactory bulb is responsible for the hyposmia in PD patients. Interestingly, this olfactory dysfunction is not found in progressive supranuclear palsy or corticobasal degeneration. In multiple system atrophy, the deficit is mild and indistinguishable from cerebellar syndromes of other aetiologies. Intact olfaction has also been reported recently in Parkin disease (PARK 2) and vascular parkinsonism. Olfactory tests may significantly enhance the diagnostic armamentarium in the differential diagnosis of parkinsonian syndromes and indeterminate tremors. Furthermore, olfactory testing may also prove to be a useful aid in the early or "preclinical" detection of PD, once effective disease-modifying therapies are found. Braak and coworkers have confirmed the widespread, extranigral pathology in PD and suggested that pathology in the anterior olfactory region may be one of the earliest appearances of neurodegeneration in PD.

[Examination of the sense of smell]. / Die Untersuchung des Riechvermögens.

Olfactory disorders are common. Functional anosmia is present in about 5-6% of the general population, while from the age of about 55 years the olfactory sense is restricted in about 25% of cases. A precise examination is necessary to describe the patient's symptoms and ascertain possible reasons for them. As far as diagnosis and possible treatment of olfactory or gustatory disorders are concerned, the main advantage allowing progress is the availability of standardised methods of testing the chemical senses. In this article procedures for orthonasal and retronasal psychophysical examination of the olfactory sense and the derivation of potentials evoked by olfactory stimuli are described. In addition, possible ways of examining the intranasal sensitivity of the trigeminal nerve and measuring the volume of the olfactory bulb, and also for immunochemical investigation of biopsies from the olfactory region, are discussed as possible means of reaching a diagnosis.