Follow-up study of olfactory deficits, cognitive functions, and volume loss of medial temporal lobe structures in patients with mild cognitive impairment.

BACKGROUND: At 3 years after diagnosis, the risk of Alzheimer disease (AD) for patients with mild cognitive impairment (MCI) is estimated to be 18% to 30%. To improve treatment of patients at high dementia risk there is a need for a better prediction of the risk for transition from MCI to AD. Olfactory deficits are a hypothetical predictor of conversion form MCI to AD. Furthermore, several studies point at volumetric reduction of medial temporal lobe structures as predictors of conversion form MCI to AD. The primary aim of this study was to evaluate whether investigations of odor deficits in MCI combined with neuropsychological tests and MRI examinations can improve prediction of the development of dementia. METHODS: Changes in olfactory functions, cognitive functions, and volume of medial temporal lobe structures (hippocampus, parahippocampal gyrus, and amygdala) were evaluated in a 24-month follow-up study in 49 MCI patients and 33 controls. RESULTS: In the MCI group, a prediction of strong cognitive functions deterioration based on poor performance in Olfactory Identification tests shows sensitivity of 57% and specificity of 88%. The test based on cognitive functions only shows a sensitivity of 44%, and 89%, respectively. Combined tests having a criteria of poor olfactory identification performance AND poor results of neuropsychological tests showed a sensitivity of 100% and specificity of 84%. Furthermore, correlation was found between the results of Olfactory Identification tests at baseline and deterioration of cognitive functions at follow up. Odor identification threshold did not appear to be a dementia predictor. A correlation of progress of cognitive function deterioration, odor identification deterioration, and decrease of volume of the hippocampus was also observed. CONCLUSIONS: Prediction of MCI to dementia conversion can be improved by supplementing the neuropsychological tests with odor identification tests. A follow up study of hippocampus volume reduction, OI performance and cognitive functions deterioration will further increase prediction accuracy.

Post-tonsillectomy dysgeusia with weight loss: possible involvement of soft palate.

OBJECTIVE: To demonstrate the importance of detailed, multidisciplinary examination of patients with post-tonsillectomy taste distortions, and to show that post-tonsillectomy dysgeusia may originate in the caudal part of the soft palate. CASE REPORT: We describe a 29-year-old man who suffered from severe post-tonsillectomy dysgeusia and phantogeusia with secondary weight loss and depression-like symptomatology. The patient had normal electrogustometric thresholds and sensitivity to touch on the posterior tongue. In contrast, elevated taste threshold and reduced sensitivity to touch was found on the caudal part of the soft palate (the palatoglossal arches). More marked elevation of electrogustometric threshold and insensitivity to touch on the right palatoglossal arch correlated with post-operative haemorrhage from the right tonsillar fossa. Psychiatric examination excluded major depression, eating disorders and drug abuse. CONCLUSIONS: Dysgeusia constitutes a rare but significant complication of tonsillectomy. Damage to the lingual branch of the glossopharyngeal nerve innervating the posterior tongue is thought to be a major cause of this complication. However, damage to the tonsillar branches of the glossopharyngeal nerve and the soft palate should also be considered as a cause of post-tonsillectomy dysgeusia. Further studies are needed to assess whether post-operative haemorrhage could indicate heightened risk of dysgeusia.

Taste responses in patients with Parkinson's disease.

OBJECTIVE: Preclinical studies indicate that dopaminergic transmission in the basal ganglia may be involved in processing of both pleasant and unpleasant stimuli. Given this, the aim of the present study was to assess taste responses to sweet, bitter, sour, and salty substances in patients with Parkinson's disease (PD). METHODS: Rated intensity and pleasantness of filter paper discs soaked in sucrose (10-60%), quinine (0.025-0.5%), citric acid (0.25-4.0%), or sodium chloride (1.25-20%) solutions was evaluated in 30 patients with PD and in 33 healthy controls. Paper discs soaked in deionised water served as control stimuli. In addition, reactivity to 100 ml samples of chocolate and vanilla milk was assessed in both groups. Taste detection thresholds were assessed by means of electrogustometry. Sociodemographic and neuropsychiatric data, including cigarette smoking, alcohol consumption, tea and coffee drinking, depressive symptoms, and cognitive functioning were collected. RESULTS: In general, perceived intensity, pleasantness, and identification of the sucrose, quinine, citric acid, or sodium chloride samples did not differ between the PD patients and controls. Intensity ratings of the filter papers soaked in 0.025% quinine were significantly higher in the PD patients compared with the control group. No inter-group differences were found in taste responses to chocolate and vanilla milk. Electrogustometric thresholds were significantly (p = 0.001) more sensitive in the PD patients. CONCLUSIONS: PD is not associated with any major alterations in responses to pleasant or unpleasant taste stimuli. Patients with PD may present enhanced taste acuity in terms of electrogustometric threshold.