The sense of smell significantly contributes to quality of life. In recent years much progress has been made in understanding the biochemistry, physiology and pathology of the human olfactory system. Olfactory disorders may arise not only from upper airway phlogosis but also from neurodegenerative disease. Hyposmia may precede motor signs in Parkinson's disease and cognitive deficit in Alzheimer's disease. These findings suggest the complementary role of olfactory tests in the diagnosis and management of neurodegenerative diseases. In this report we present a review of modern olfactory tests and their clinical applications. Although rarely employed in routine clinical practice, the olfactory test evaluates the ability of odour identification and is a useful diagnostic tool for olfaction evaluation. Olfactory screening tests are also available. In this work we strongly recommend the importance of an ENT evaluation before the test administration and dissuade from a self-administration of an olfactory test.

Mild cognitive impairment (MCI) is a transient status between physiologic ageing and dementia. Each year more than 12% of subjects with MCI develop Alzheimer's disease. This study evaluated the presence of an olfactory deficit in amnesic MCI (aMCI) patients. Twenty-nine patients diagnosed with aMCI and a homogeneous control group of 29 subjects were enrolled in the study. Olfactory function was assessed by the Sniffin' Sticks Screening Test (SSST) and the Mini Mental State Examination, the Clinical Dementia Rating, the Geriatric Depression Scale and the Mental Deterioration Battery were used to evaluate the neurocognitive status. aMCI patients showed a significant impairment of their olfactory identification compared to controls (SSST score: 8.3+/-2.1 vs. 10.8+/-0.9; p<0.001). These results suggest that olfactory tests should be part of the diagnostic armamentarium of pre-clinical dementia. A long-term follow up might confirm the olfactory identification function as an early and reliable marker in the diagnosis of pre-clinical dementia.

Patients with tinnitus are heterogeneous and several factors influence the impact of this symptom on the quality of life. The aim of the study is to evaluate the relationship between age, gender, sleep disorders, hyperacusis and tinnitus annoyance and to demonstrate the utility of tinnitus questionnaires as screening tools for sleep disorders and hyperacusis in patients with tinnitus. 37 consecutive patients (18 males and 19 females) with subjective tinnitus lasting over 3 months were evaluated with a complete interview, otological examination, pure tone audiometry, Italian version of tinnitus sample case history (TSCH) and tinnitus handicap inventory (THI). Statistical analysis was performed with the Wilcoxon's rank sum test, the Spearman's rho non-parametric correlation and the logistic regression analysis. THI grades were slight (16%), mild (32%), moderate (30%), severe (19%) and catastrophic (3%). Based on the answers to TSCH 20 patients reported sleep disorders (54%) and 20 patients reported hyperacusis (54%). 11 patients (30%) reported sleep disorders and hyperacusis. No significant correlation was found between the severity of tinnitus and patients' age and gender. Significant correlation was found between sleep disorders (P = 0.0009) and tinnitus annoyance and between hyperacusis (P = 0.03) and tinnitus annoyance. TSCH and THI may be considered as screening tools in the clinical practice to evidence sleep disorders and hyperacusis in patients with tinnitus.

Our findings suggest the potential utility of olfactory test and hippocampal volume loss for early detection of AD.

Tinnitus is a perception of sound in absence of sound stimulation. Tinnitus in many cases cannot be eliminated by conventional medical treatment with drugs or surgery. Some people who begin to notice tinnitus, whether spontaneous or induced by noise, trauma or other insult, will experience spontaneous resolution, but many patients will have persistent tinnitus. For some of them, tinnitus sensation will be joined by tinnitus suffering, with many adverse effects like anxiety, depression and sleep disorders. For these tinnitus sufferers the psychological and acoustic approach proposed by the Tinnitus Retraining Therapy and Acoustic Desensitization Protocol may be helpful. Periodically new treatments are suggested like low-frequency repetitive transcranial magnetic stimulation and sequential phase shift sound cancellation treatment based on the frequency and loudness matching of the tinnitus. The aim of this work is to review modern considerations for the treatment of tinnitus.