Alzheimer Disease: Lehrner J

Lehrner J, Gufler R, Guttmann G, Maly J, Gleiss A, Auff E, Dal-Bianco P. · University Clinic of Neurology, Medical University of Vienna, Vienna, Austria. · Wien Klin Wochenschr. · Pubmed #16416345 No free full text.

Abstract: OBJECTIVE: The goals of this study were to determine the annual conversion rate to Alzheimer disease (AD) among patients reporting memory problems, including a subgroup with amnestic mild cognitive impairment (aMCI), and to investigate the predictive value of neurocognitive testing for future dementia. METHODS: A prospective study was carried out in an outpatient memory clinic. One hundred and seven patients underwent a clinical examination and completed a battery of standard cognitive tests at study entry and two years later. The conversion rate to clinically manifested AD two years later was investigated and sensitivity, specificity, receiver operating characteristics (AUC), positive predictive value and negative predictive value for each neuropsychological test were determined. RESULTS: We found an annual rate of conversion to AD of 6.5% among patients reporting memory decline in the setting of our clinic. Specifically, patients with aMCI had an annual conversion rate of approximately 20%. The annual conversion rate for patients reporting memory problems but showing no memory deficit at memory testing was approximately 3%. Receiver operating characteristics (AUC) of the neuropsychological tests ranged from 0.60 to 0.94. CONCLUSIONS: Patients with aMCI have 8.6-fold higher odds of developing AD compared with patients without evident memory impairment on neuropsychological testing. Although the risk of developing AD among patients without objective memory decline is small, some patients in this group still convert to AD and therefore close clinical monitoring of patients is necessary.

Walla P, Püregger E, Lehrner J, Mayer D, Deecke L, Dal Bianco P. · Department of Clinical Neurology, University Hospital, Medical University Vienna, Austria. · J Neural Transm. · Pubmed #15480853 No free full text.

Abstract: Effects related to depth of verbal information processing were investigated in probable Alzheimer's disease patients (AD) and age matched controls. During word encoding sessions 10 patients and 10 controls had either to decide whether the letter "s" appeared in visually presented words (alphabetical decision, shallow encoding), or whether the meaning of each presented word was animate or inanimate (lexical decision, deep encoding). These encoding sessions were followed by test sessions during which all previously encoded words were presented again together with the same number of new words. The task was then to discriminate between repeated and new words. Magnetic field changes related to brain activity were recorded with a whole cortex MEG.5 probable AD patients showed recognition performances above chance level related to both depths of information processing. Those patients and 5 age matched controls were then further analysed. Recognition performance was poorer in probable AD patients compared to controls for both levels of processing. However, in both groups deep encoding led to a higher recognition performance than shallow encoding. We therefore conclude that the performance reduction in the patient group was independent of depth of processing. Reaction times related to false alarms differed between patients and controls after deep encoding which perhaps could already be used for supporting an early diagnosis.The analysis of the physiological data revealed significant differences between correctly recognised repetitions and correctly classified new words (old/new-effect) in the control group which were missing in the patient group after deep encoding. The lack of such an effect in the patient group is interpreted as being due to the respective neuropathology related to probable AD. The present results demonstrate that magnetic field recordings represent a useful tool to physiologically distinguish between probable AD and age matched controls.