Sensitivity and specificity of Addenbrooke's Cognitive Examination, Mattis Dementia Rating Scale, Frontal Assessment Battery and Mini Mental State Examination for diagnosing dementia in Parkinson's disease.

INTRODUCTION: Among the non-motor features of Parkinson's disease (PD), cognitive impairment is one of the most troublesome problems. Highly sensitive and specific screening instruments for detecting dementia in PD (PDD) are required in the clinical practice. METHODS: In our study we evaluated the sensitivity and specificity of different neuropsychological tests (Addenbrooke's Cognitive Examination, ACE; Frontal Assessment Battery, FAB and Mattis Dementia Rating Scale, MDRS) in 73 Parkinson's disease patients without depression. By receiver operating characteristic curve analysis, these screening instruments were tested against the recently established clinical diagnostic criteria of PDD. RESULTS: Best cut-off score for ACE to identify PDD was 80 points (sensitivity = 74.0%, specificity = 78.1%). For FAB the most optimal cut-off value was 12 points (sensitivity = 66.3%, specificity = 72.2%); whereas for MDRS it was 125 points (sensitivity = 89.8%, specificity = 98.3%). Among the examined test batteries, MDRS had the best clinicometric profile for detecting PDD. CONCLUSION: Although the types of applied screening instruments might differ from movement disorder clinic to clinic within a country, determination of the most specific and sensitive test for the given population remains to be an important task. Our results demonstrated that the specificity and sensitivity of MDRS was better than those of ACE, FAB and MMSE in Hungary. However, further studies with larger sample size and more uniform criteria for participation are required to determine the most suitable screening instrument for cognitive impairment.

Egocentric mental rotation in Hungarian dyslexic children.

A mental rotation task was given to 27 dyslexic children (mean age 9 years, 2 months) and to 28 non-dyslexic children (mean age 8 years, 8 months). Pictures of right and left hands were shown at angles of 0, 50, 90 and 180 degrees, and the subjects were required to indicate whether what was shown was a right hand or a left hand. It was found that, in this task, the dyslexics did not show the normal pattern of response times at different angles, and also, that they made more errors than the controls. It is argued that this result is compatible with hypothesis that, in typical cases of dyslexia, there is a malfunctioning in the posterior parietal area.

Cognitive subprocesses of mental rotation: why is a good rotator better than a poor one?

The Vanderberg-Kuse Mental Rotation Test is a standard test of mental rotation ability. Recent experiments have demonstrated that mental rotation is a complex cognitive process wherein different subprocesses (focused attention, visual scanning, perceptual decision, visual memory) play important roles in performance. We classified the population as good and poor rotators by performance of mental rotation (ns = 47: 22 men and 25 women, respectively; mean age: 20.7 yr.). To examine differences cognitive subprocesses of mental rotation of these two groups were compared. There were significant differences between poor and good rotators in performance on Raven's test and the Pieron Focused Attention test scores. The good rotators scored better because their perceptual decision-analytical intelligence (Raven) and focused attention scores were higher.

Sex differences on the hand mental rotation task for 9-yr.-old children and young adults.

The Hand Mental Rotation task is assumed to activate an egocentric spatial reference frame to realize mental rotation. This study presents significant sex differences in hand mental rotation performances between men and women (n = 23 and 25, respectively; age: 20.7 yr.). Differences in hand mental rotation in school girls and boys (ns = 48 and 41, respectively; age: 9 yr.) were not significant. Our results suggest that the change in sex differences in egocentric mental rotation may occur with developmental change. This requires further testing with a larger sample so testing can occur at several ages between 9 and 20.7 years.

The indirect verification of minimal two-generator model of homeostatic drinking by complexity examination.

In the course of previous examinations, it has been suggested that minimally two lick pattern generators have to take part in the formation of temporal patterns of homeostatic drinking. The drinking pattern of five rats was investigated, subsequently analysed and compared to simulated data. As the interaction of the two generators changes by the progress of satiation, the dynamics of drinking have to change too. In this experiment we demonstrated this nonlinear dynamical change by the examination of algorithmic complexity which reflects the nature of motivational changes and that the proportion of the change of complexity is in harmony with our model of homeostatic drinking.