[Cognitive training in Alzheimer's dementia]. / Kognitives Training bei Alzheimer-Demenz. Aktuelle Entwicklungen, Chancen und Grenzen gerontologischer Gedächtnisrehabilitation.

Memory rehabilitation in dementia patients is gaining importance. Among the increasing number of people affected by Alzheimer's dementia (AD), the number detected in early stages of the disease is growing disproportionately quickly. The reasons are obvious: improved clinical assessment in the initial disease stage, increased sensitization of the elderly towards cognitive deficits, and the prescription of drugs retarding cognitive decline. Given the limited success of early training programs in the 1980s, skepticism towards cognitive training in dementia is still common among clinicians. However, recent international studies in the field give reason for cautious optimism. Memory therapy in the early-to-moderate stages of AD can be successful, if it is tailored to patients' individual daily problems and based on their residual cognitive capacities. The present paper gives an overview of recent findings in clinical and cognitive neuroscience which have led to a conceptual change in the memory rehabilitation of patients with dementia. Based on a review of general principles and rehabilitation techniques proven successful in recent research, recommendations are formulated for future studies evaluating cognitive therapy in dementia.

Retrieval of long and short lists from long term memory: a functional magnetic resonance imaging study with human subjects.

Previous studies have shown that reaction time in an item-recognition task with both short and long lists is a quadratic function of list length. This suggests that either different memory retrieval processes are implied for short and long lists or an adaptive process is involved. An event-related functional magnetic resonance imaging study with nine subjects and list lengths varying between 3 and 18 words was conducted to identify the underlying neuronal structures of retrieval from long and short lists. For the retrieval and processing of word-lists a single fronto-parietal network, including premotor, left prefrontal, left precuneal and left parietal regions, was activated. With increasing list length, no additional regions became involved in retrieving information from long-term memory, suggesting that not necessarily different, but highly adaptive retrieval processes are involved.

Differential behaviors toward ultraviolet A and B radiation of fibroblasts and keratinocytes from normal and DNA-repair-deficient patients.

Xeroderma pigmentosum (XP) and trichothiodystrophy (TTD) are rare genodermatoses transmitted as recessive and autosomal traits that result in reduced capacity to repair UV-induced DNA lesions. Although XP, but not TTD, patients are prone to basal and squamous cell carcinomas, to date no comparative studies of the XP and TTD phenotypes have included epidermal keratinocytes. We compared the DNA repair capacity (by unscheduled DNA synthesis) and cell survival (by clonal analysis) of epidermal keratinocytes and dermal fibroblasts grown from normal individuals and patients with xeroderma pigmentosum and trichothiodystrophy following UVA and UVB irradiation. The same dose of UVB (1000 J/m2) induced twice as many DNA lesions in normal fibroblasts as in normal keratinocytes. UV survival rates were always higher in keratinocytes than in fibroblasts. Normal and TTD keratinocytes survived better following UVA and UVB irradiation than XP-C and XP-D keratinocytes. XP-C keratinocytes exhibited exacerbated sensitivity toward UVA radiation. Unscheduled DNA synthesis at UV doses leading to 50% cell survival indicated that the ratio of DNA repair capacity to cell survival is higher in keratinocytes than in fibroblasts. In addition, UVA and UVB irradiation induced a transition from proliferative to abortive keratinocyte colonies. This transition varied between donors and was in part correlated with their cancer susceptibility. Altogether these data provide the first evidence of the differential behaviors of normal, XP, and TTD keratinocytes toward UV radiation.