Mild Cognitive Impairment and Depressive Symptoms in Patients with Wilson's Disease under Long-Term Therapy

Introduction: Wilson's disease is a rare autosomal recessive disorder of hepatic copper transport leading to a biliary excretion inhibition of copper. Overloading of the metal mainly in the liver and basal ganglia leads not only to hepatic but also to extrapyramidal motor as well as psychiatric clinical symptoms. Cognitive dysfunction is often reported and patients suffer from additional depressive symptoms. Methods: In this study, a cognitive impairment profile with SIDAM (SISCO) including mini-mental state, digit span and the trail making test was performed in 32 patients with Wilson's disease (24 patients with the neurological form, 8 patients with the non-neurological form) undergoing long-term medicamentous therapy. The extent of neurological impairment was assessed in a neurology score. The Beck depression inventory (BDI) was used for the detection of depressive symptoms. Results of cognitive testing and BDI score were correlated with the results of the clinical investigation. Results: Median results of MMSE, SIDAM, part of digit span and trail-making test are significantly worse in patients with the neurological form of Wilson's disease. There is no significant difference in median results of BDI, although the number of patients with a score suggesting a mild depressive disorder is higher in the group with the neurological form. The median result of SIDAM was 52 (45 - 55) in the neurological form and 54 (53 - 55) points in the non-neurological form. There is no statistical significance in the correlation to the severity of the neurological score. Conclusions: Depressive symptoms and cognitive impairment in Wilson's disease are frequently reported by patients who are on long-term treatment. In particular, the ability to concentrate and undertake executive functions are affected in the neurological form of Wilson's disease while functions of memory are less impaired. Since movement disorders often have improved with therapy, additional observation of cognitive function and depressive disorders seems to be useful. However, mild cognitive impairment occurs independently of the severity of the neurological symptoms.