Clinical assessment of patients with smell and taste disorders



The use of clinical tests has been proposed as efficient tools to evaluate olfactory and taste deficiencies. These tests assess the level of alteration of the disorder, being more common the olfactory loss, since 80% of the flavor of a meal is the result of the intervention of the sense of smell. Before performing a direct treatment, a clinical evaluation of the patient’s smell and a physical examination is necessary, following certain guidelines. Nasal endoscopy is especially useful to identify the obstructive causes of olfactory loss, where attention should be paid to the permeability of the olfactory cleft and the middle meatus, or to the presence of polyps or tumors, among other aspects.

The two most common olfactory etiological factors are conductive losses (nasal and sinus obstruction) and sensory losses (head trauma, exposure to toxins, among others). Furthermore, olfaction sensitivity decreases with age, as well as after nasal surgery or due to psychiatric disorders, such as depression and schizophrenia. There are two main olfactory tests to measure its affection and evaluate its capacity, which are each subdivided into various tess; the first includes psychophysical tests. This group includes olfactory threshold tests, odor identification tests (UPSIT) or intercultural odor identification tests (CC-SIT, variant of the UPSIT). The second includes electrophysiological tests, such as the electro-olfaction (EOG) or the odor-related potentials (OERP), which are generally used for research.

On the other hand, different causes coexist that can generate taste disorders, such as viral, bacterial, fungal or parasitic infections of the oral mucosa, among others. To assess these causes, it is necessary to measure the ability of the sense of smell and the quality and intensity of taste. Two types of tests are used: “Magnitude Matching” or spatial test, and electrogustometry. It must be mentioned that the loss of taste is mainly due to the disorders of the sense of smell; therefore, it is essential to make a complete diagnosis, both physical and neurological of the patient, to know what treatments to apply in order to improve their disorder.

As a critical vision, four fields are missing in the work: the clarification of the advantages and disadvantages of each test, a comparison between the most qualified and less convenient tests, the explanation of the reason for the use of different methods in the field of the investigation or of the diagnoses and finally, to expose the positive or negative results in the tests particularly in all the cycles of the life of the man: from childhood to elderly.