Clinical assessment of patients with smell and taste disorders

Clinical assessment of the patient who has smell and taste disorders requires understanding of the etiology of the olfactory and gustatory disorders. Available clinical tests of olfactory and gustatory systems allow detecting and measuring the degree of the sensory loss, but are unable to determine the cause and give neither prognostic information nor therapeutic guidance. With physical examination, however, clinical history can help to establish the diagnosis and guide the treatment if available. A clinician evaluating a patient who has smell and taste loss must understand that "taste" complaints usually are symptoms of an olfactory dysfunction. The distinction between true gustatory loss (bitter, sweet, salty, sour, or umami) and olfactory loss, the inability to perceive complex flavors of food, will help clarify the patient's diagnosis. Easy-to-administer tests are available for olfactory (eg, UPSIT) and gustatory testing (eg, spatial tests, taste sticks, tasting tablets). In rare circumstances, imaging studies (eg, MRI, CT) are indicated.     

Clinical characteristics of taste and smell disorders

Chemosensory problems can have major consequences for those patients who develop them. Although more than 200 conditions and 40 medications have been linked to taste and smell disorders, for most patients the cause will fall into one of the following categories: nasal/sinus disease, idiopathic, postviral URI, and head trauma. Careful attention to clinical characteristics will aid immensely in the diagnosis. Parosmias, dysgeusias and the burning mouth syndrome are symptoms that deserve special consideration.     

Initial otolaryngologic assessment of patients with taste and smell disorders

Patients are often referred to otolaryngologists to evaluate dysfunctions of taste or smell. A history and physical examination focused on signs and symptoms of chemosensory disorders, in combination with screening tests for taste and smell function, can quickly and easily delineate the general type and cause of the dysfunction. Several centers for chemosensory disorders referred to in this issue are available for referral to patients who need detailed testing and evaluation. Although treatment options for most taste and smell dysfunctions are limited, by categorizing disorders, we can give the patient an idea of the probable cause and prognosis of the dysfunction.     

Medical management of taste and smell disorders

Chemosensory dysfunction is most often secondary to one of only a few causes: nasal/sinus disease, viral infection, toxic chemical exposure, head trauma, as well as medication-related and idiopathic conditions. Medication-related disorders are corrected by discontinuance of the causative medicine. Our experiences have also shown that only dysfunctions of smell caused by disorders of the nose and/or sinuses are amendable to therapy.     

Office management of taste and smell disorders.

Chemosensory disorders have been receiving increasing clinical attention but remain a difficult diagnostic problem. With the development of several well-standardized testing methods, taste or smell loss can now be verified, and this has added to knowledge concerning the common causes of dysfunction. Diagnosis typically rests upon the history and physical examination, but, except in the case of obstructive nasal and sinus pathologic conditions, therapy usually remains elusive.     

Experiences with smell and taste studies in 798 patients

We present our experiences of olfactometry and gustometry on 798 patients. The results show the necessity of combining tests for both taste and smell. They are essential components of the complete neuro-otological examination and should remain in the otorhinolaryngologist's repertoire.     

Post-traumatic taste and smell disorders: forensic aspects

The impact of anosmia or ageusia may be considerable for some occupations. Expert assessment shows how difficult it is to prove the diagnosis. A specialist is usually needed to demonstrate the asserted disorder. Damage compensation is based on the patient's occupation and coverage.     

Assessment of smell and taste in patients with allergic rhinitis

We examined the senses of smell and taste in 240 patients with verified hypersensitivity reactions of the respiratory tract. Olfactometry was performed according to Elsberg and Levy's method and followed by electrogustometry. The examinations revealed that the incidence of smell and taste disorders in patients with allergic rhinitis is 21.4% and 31.2%, respectively. No significant relationships between smell and taste dysfunction were found. We evaluated statistically positive correlations between the olfactory and gustatory thresholds compared with 78 qualitative and quantitative factors assessed in the study. There was a statistically significant relationship between the olfactory thresholds and levels of eosinophils in blood and in nasal discharge. acid reaction of the nasal mucosa, coexisting nasal polyps and X-ray changes in the ethmoid sinuses. There was a positive influence of pharmacotherapy as well as specific desensitization and surgery on the impairment of the sense of smell in allergic rhinitis.     

Hearing disorders in patients with insulin-dependent diabetes mellitus

The cochlear and retrocochlear hearing function was evaluated in patients with long- and short-term insulin-dependent diabetes mellitus (IDDM) by means of psychoacoustic testing and auditory brain stem responses (ABR). Twenty patients with diabetic microangiopathy (median age 41 years, range 25-66 years) were examined. The median duration of their diabetes was 26 years (range 13-46 years). In addition, 19 patients without microangiopathy (median age 27 years, range 17-42 years) and with a median duration of the diabetes of 2 years (range 0-6 years) were examined. The metabolic control estimated by blood glucose concentration and glycosylated haemoglobin was identical in the two groups of IDDM patients. After correction for age and sex, no significant differences in hearing thresholds or discrimination scores were present between the two diabetic groups, or between the diabetic patients and an age- and sex-matched normal background population. In the patients with long-term IDDM, ABR produced abnormal responses in 40%, indicating the presence of diabetic encephalopathy, whereas ABR were abnormal in only 5% of the patients with short-term IDDM.     

Disorders of smell and taste

This article describes the anatomy and physiology of the gustatory and olfactory organs in man. Dysfunction of these senses is closely examined with respect to etiology, diagnosis, and treatment. Taste and smell are closely interrelated. An influence on the function of one sense often affects the function of the other sense.     

Physiology of smell and taste]

The functional organization of olfaction and taste are briefly discussed in morphological, physiological, biochemical and behavioural terms. Olfaction in animals serves often for long range navigational purposes whereas taste acts as a close up "last moment food checking system". Special attention is given to the coding problems in both systems. In taste, the spatial coding mode is prevalent. In olfaction a very complex coding system exists, which used temporal as well as spatial means and in which a whole set of olfactory nerve fibers is activated during the transmission of any specific odor information, each fiber of the set discharging at a specific impulse pattern. The role of the olfactory bulb is seen as an integrating center with the capabilities for short and long term information storage. The impact of von Békésy's microstimulation experiments on the physiology of taste is discussed. Research on taste modifiers such as gymnemic acid or of the taste modifying protein "miraculin" enrich our present understanding of the interaction between taste stimulants and the chemoreceptor sites in the taste buds.     

Nutrition and taste and smell dysfunction

Food selection plays a pivotal role in maintaining adequate nutrient intake, thus elucidating drivers of food choice is a meaningful strategy to maintain health and manage disease. Taste and smell are key determinants of food choice and warrant careful consideration. In this review, we first discuss how sensory stimulation influences food selection and metabolism. We then review the evidence regarding the relationship between taste and smell dysfunction and food preferences and selection, with attention given to contexts of certain chronic diseases. We conclude with brief recommendations for the management of chemosensory disorders. While sensory abilities influence food selection, the effect of taste and smell dysfunction on long-term consumption patterns and health status must be considered in light of environment, exposure, and culture.     

糖尿病患者前庭功能的改变及其临床意义

目的:探讨糖尿病患者前庭功能的改变及其临床意义.方法:对76例糖尿病患者(糖尿病组)和60例健康成年人(对照组)用跟震电图测试仪进行自发性眼震试验、位置试验、摇头试验、转颈试验、温度试验和视眼动系统检查(凝视试验、扫视试验、平稳跟踪试验),对上述各项试验数据进行相应的定性及定量分析.结果:糖尿病组前庭功能异常为68.4%,对照组为8.3%,两组比较差异有统计学意义(x2=15.472,P＜0.01).结论:糖尿病患者的眩晕症状与前庭功能减退有一定关系,且多为外周性眩晕,眼震电图可提供客观的临床检测.     

震动眼震在单侧前庭外周疾病中的临床意义

目的研究震动眼震（vibration—induced nystagmu，VIN）在前庭外周疾病诊断中的临床意义，并确定震动实验（vibration test，VT）的灵敏度和特异度。方法30例健康成人和眩晕门诊112例单侧外周前庭疾病患者纳入本研究，排除具有自发性眼震患者，采用置于乳突和前额的震动刺激（92Hz）进行震动实验，观察记录VIN的诱发情况，患者和正常受试者同时还进行摇头眼震（headshaking nystagmus，HSN）和前庭双温冷热试验检查，并进行比较。结果112例患者中，有91例（81％）出现VIN，主要是水平眼震，VIN在乳突比在前额更常诱发出，其中76例VIN的方向朝向健侧，然而15例梅尼埃病患者VIN方向朝向患侧。30例健康受试者，均未出现VIN。随着前庭双温冷热试验中半规管轻瘫（canal paresis，CP）值的增加，VIN出现率增加。分别有70例（63％）单侧外周前庭疾病患者和9例健康受试者（30％）出现HSN。前庭双温检查，112例患者中CP值〈25％有10例，25％≤CP值≤40％有32例，40％〈CP值〈70％有48例，cP值≥70％有22例，30例健康受试者CP值均〈25％，VIN出现率随着cP值的增加而增加。结论VIN检查是一项简单、非侵入性的、患者能很好耐受的检测单侧外周前庭功能障碍的临床测试方法，具有比HSN检查更高的灵敏度和特异度。     

Dysfunction of the chemical senses smell and taste

Dysfunction of the senses of taste and smell may strongly affect our lives. During the last years reliable techniques for the standardized investigation of the 2 senses have been introduced to clinical routine. These techniques are highly standardized and can be easily used, for example, for quality control before and after surgery. Although there are proven therapeutic approaches to taste or smell loss, by far not all patients can be helped. New ideas need to tested within rigorous double-blind studies. The regenerative capacity within the chemical senses provides a major basis for hopes on therapeutic success.