Effekt von Zink auf die Olfaktion und Motorik von Patienten mit Morbus Parkinson

Recently, PD patients have been shown to have a decreased zinc level in cerebrospinal fluid and to suffer from functional zinc deficiency. The lack of this trace metal is usually associated with smell dysfunction. Since the majority of PD patients suffers from hyposmia, we hypothesized that treatment with zinc could reverse olfactory impairment in these patients and investigated its efficiency for the treatment of hyposmia an motor dysfunction in a small-sized study ("proof-of-principle"). In the treatment group, patients were treated with 25 mg zinc per day for three months. Patients in the control group did not receive any additional medication. Olfactory impairment was measured using "sniffing sticks" at baseline and after three months. "Sniffing sticks" are a validated tool for the measurement of the olfactory threshold and of odor discrimination and identification. Primary endpoint was the change in the identification score after three months. Secondary endpoints were the changes in the olfactory threshold, the odor discrimination scores, the UPDRS II and III scores, and the motor function as measured by a three-dimensional ultrasound motion analyser (Zebris Medizintechnik, Germany). Besides the functional zinc status and the serum zinc and copper levels were examined. Other causes of hyposmia were excluded by rhinoscopy before inclusion into this study. 16 PD patients presenting with olfactory impairment have been enrolled in this study. Analysis of the data has shown that the hyposmia neither decreased nor increased significantly in one of the groups. Similar data were obtained for the secondary endpoints. These results indicate that a) zinc is not an efficient treatment for olfactory impairment in PD, b) zinc deficiency in PD is not causally linked to hyposmia in PD and c) zinc is not an efficient treatment for motor dysfunction.