Subtle Extrapyramidal Signs and Incident Dementia: A Follow-up Analysis

We previously reported [1] that the presence of mild extrapyramidal signs (EPS) significantly predicts Alzheimer's disease (AD) in elderly individuals, independent of age, education, or gender. We now report a confirmation of our data after accrual of more cases and additional follow-up assessments

Verhaltensmodell für Softwareagenten im Public Goods Game

Gegenstand der vorliegenden Arbeit ist das Verhaltensmodell von Softwareagenten in einem Public Goods Game. Agenten im Sinne der Arbeit besitzen jeweils eigene, individuelle Ziele und müssen sich im Hinblick auf ein übergeordnetes Gesamtziel im Multiagentensystem koordinieren. Dabei hängen die individuell und kollektiv erzielbaren Ergebnisse von der Wahl der Verhaltensmodelle der Agenten ab. Die Wahl eines rein eigennützigen Verhaltens kann zu Nutzeneinbußen führen; die Wahl eines selbstlosen Verhaltens kann die individuell erzielbaren Ergebnisse eines Agenten massiv beeinträchtigen, falls andere Agenten im System eigennützig spielen. Die Auswirkungen verschiedener, aus der sozio-ökonomischen Theorie entlehnter Verhaltensmodelle in unterschiedlich gestalteten Agenten-Gesellschaften wird mittels einer Simulation untersucht. Die vorliegende Arbeit soll somit einen Beitrag liefern, um auf Basis deskriptiver sozio-ökonomischer Verhaltensmodelle Aussagen über das Verhalten von Softwareagenten (präskriptive Modelle) zu erlauben. Die Erkenntnisse helfen Entwicklern von Multiagentensystemen bei der Implementierung eines problemadäquaten Agentenverhaltens

Comparison of Cognitive Changes in Patients with Alzheimer's and Parkinson's Disease

Objective. —To compare cognitive changes in the dementias of Parkinson's disease (PD) and Alzheimer's disease (AD). Design. —Case series, group comparisons. Setting. —Ambulatory care referral center. Patients. —Consecutive sample of 14 patients with PD dementia and 27 with probable AD matched for overall intellectual function using a mental status test, as well as 1 nondemented PD and 12 mild probable AD patients, similarly matched for overall intellectual function. All demented patients met Diagnostic and Statistical Manual, Revised Third Edition, criteria for dementia. Main Outcome Measures. —Performance on a battery of neuropsychological tests assessing verbal and nonverbal memory, verbal fluency, and constructional ability. Results. —Nondemented and demented patients with PD performed worse than their probable AD comparison groups on verbal fluency and visuospatial tasks. Cognitive changes attributable to dementia were similar in PD and probable AD but were not identical. The patients with probable AD demonstrated more marked change in memory performance with delay. Conclusions. —Our findings suggest that when dementia occurs in PD it is overlaid on cognitive changes that already exist in nondemented patients but that the dementing process in PD involves systems other than those responsible for cognitive change in nondemented PD patients. We hypothesize that in most cases, dementia in PD involves changes in a nondopaminergic neurotransmitter system but is not due to concomitant AD

Relationships between Extrapyramidal Signs and Cognitive Function in a Community-Dwelling Cohort of Patients with Parkinson's Disease and Normal Elderly Individuals

The relationship between extrapyramidal sign(DPS) severity and cognitive funcition was investigated in 184 patients with indiopathic Parkinson's disease (PD) and 301 normal elderly individuasls from a community-dwelling cohort in northern Manhattan, New York City. Fifiy-six of the patients with PD met criteria for dementia of the Diagnostic and Statistical Manual of Mental Disorders third edition, revised, and of the National Institute of Neurological and Communicative Disorders and Stroke-Alzbeimer's Disease and Related Disorders Association. EPS were rated according to the Unified Parkinson's Disease Rating Scale. Cognitive function was assessed by neuropsychological rests of memory, orientation, abstract reasoning, language, construcion, and psychomotor speed. Significant associations were found between EPS and neuropsychological performance in PD partients without dementia. Yet EPS severity was unable to account for the pronounced cognitive impairment in PD dementia. Individuals in the normal group with subtle EPS, but withtout overt idiopathic PD, showed widespread cognitive changes, including imparment in most of the tests that differentiated PD patients from normal subjects. Prospective follow-up of these individuals will determine whether this represents a preclinical stage of PD or constitutes an early manifestation of dementia

Relationships between Extrapyramidal Signs and Cognitive Function in a Community-Dwelling Cohort of Patients with Parkinson's Disease and Normal Elderly Individuals

The relationship between extrapyramidal sign(DPS) severity and cognitive funcition was investigated in 184 patients with indiopathic Parkinson's disease (PD) and 301 normal elderly individuasls from a community-dwelling cohort in northern Manhattan, New York City. Fifiy-six of the patients with PD met criteria for dementia of the Diagnostic and Statistical Manual of Mental Disorders third edition, revised, and of the National Institute of Neurological and Communicative Disorders and Stroke-Alzbeimer's Disease and Related Disorders Association. EPS were rated according to the Unified Parkinson's Disease Rating Scale. Cognitive function was assessed by neuropsychological rests of memory, orientation, abstract reasoning, language, construcion, and psychomotor speed. Significant associations were found between EPS and neuropsychological performance in PD partients without dementia. Yet EPS severity was unable to account for the pronounced cognitive impairment in PD dementia. Individuals in the normal group with subtle EPS, but withtout overt idiopathic PD, showed widespread cognitive changes, including imparment in most of the tests that differentiated PD patients from normal subjects. Prospective follow-up of these individuals will determine whether this represents a preclinical stage of PD or constitutes an early manifestation of dementia

Interrater Reliability of Extrapyramidal Signs in a Group Assessed for Dementia

Extrapyramidal signs were rated by three neurologists in 20 patients who had either been diagnosed as having probable Alzheimer's disease or who were being evaluated for dementia. In general, good inter-rater reliability was found for the presence or absence of extrapyramidal signs, although agreement over the presence of some signs was reduced when distinctions between normality and slight departures from normality were required

Quantum Chaos in Open versus Closed Quantum Dots: Signatures of Interacting Particles

This paper reviews recent studies of mesoscopic fluctuations in transport through ballistic quantum dots, emphasizing differences between conduction through open dots and tunneling through nearly isolated dots. Both the open dots and the tunnel-contacted dots show random, repeatable conductance fluctuations with universal statistical proper-ties that are accurately characterized by a variety of theoretical models including random matrix theory, semiclassical methods and nonlinear sigma model calculations. We apply these results in open dots to extract the dephasing rate of electrons within the dot. In the tunneling regime, electron interaction dominates transport since the tunneling of a single electron onto a small dot may be sufficiently energetically costly (due to the small capacitance) that conduction is suppressed altogether. How interactions combine with quantum interference are best seen in this regime.Comment: 15 pages, 11 figures, PDF 2.1 format, to appear in "Chaos, Solitons & Fractals

The Columbia University Scale for Psychopathology in Alzheimer's Disease

The Columbia University Scale for Psychopathology in Alzheimer's disease is a new screening instrument developed for use by clinicians or trained lay interviewers. Interrater reliability was established between a psychiatrist and a lay interviewer in 20 patients. In an independent sample of 91 outpatients with very mild to moderate probable Alzheimer's disease, caregiver informants reported that depressed mood was common (46.2%) but rarely persistent (2.2%), and that sleep disturbance occurred frequently (41.8%) but was never severe (0%). There were significant but weak associations between the presence of specific subtypes of delusions and severity of dementia. Although a variety of delusional symptoms were reported, they were frequently transient and patients often accepted the truth if corrected by the caregiver. As a result, few patients met broad or narrow operational criteria used to define delusions. Prior studies may have overestimated the prevalence of psychotic features in Alzheimer's disease by not employing standard definitional criteria. The findings also indicate that new methodology such as that employed in this instrument needs to be evaluated more widely