Transcranial Stimulation Aids Naming in Poststroke Aphasia
NEW YORK, April 8 (Reuters Health)—Transcranial direct current stimulation (tDCS) appears to improve the accuracy of naming pictures by patients with poststroke aphasia, Italian researchers reported in the April Journal of Neurology, Neurosurgery, and Psychiatry.

Dr. Alberto Priori and colleagues at the University of Milan evaluated the effect of tDCS over the left frontotemporal areas in eight chronic nonfluent poststroke aphasic patients. The procedure involves delivery of a 2 mA current for 10 minutes to two electrodes—one on the cranium, the other above the right shoulder.

The team assessed the accuracy and response time of naming of items shown on a computer screen. Images were selected from prepared lists. This was done before and immediately after anodal or cathodal tDCS and sham stimulation.

The anodal tDCS and sham tDCS failed to induce any changes. However, cathodal tDCS improved the accuracy of the picture naming by a significant 33.6%.

Regardless of the underlying mechanism, the researchers concluded that the approach “is simple, safe and inexpensive and thus it might possibly be useful in the management of poststroke aphasia.”

Dr. Stefano F. Cappa, author of an accompanying editorial, told Reuters Health that “these studies indicate that it is possible to improve performance on a language task by means of external stimulations applied to the damaged brain.”

Nevertheless, Dr. Cappa, of Vita-Salute San Raffaele University, Milan, added that “it is important to underline that there is currently no evidence that the improvements may be persistent or have any impact on real-life communication abilities.”

However, he concluded, “The results provide sufficient background for projects aimed at testing these methodologies in adequate clinical trials.”

J Neurol Neurosurg Psychiatry. 2008;79(4):451-453, 364.

Dementia a Frequent Consequence of Parkinson’s Disease
NEW YORK, April 10 (Reuters Health)—Dementia is a part of Parkinson’s disease for most patients and reduces survival, researchers in Norway reported. The likelihood of developing dementia also increases with age.

“The absolute risk of dementia and how it affects survival in Parkinson’s disease are not known,” according to Dr. Dag Aarsland, of Stavanger University Hospital, and colleagues.

The researchers previously reported the overall incidence and eight-year cumulative prevalence of dementia in Parkinson’s disease. In the current study, the patients were reevaluated at regular intervals after their baseline evaluation. The findings are reported in the March 25 Neurology.

A diagnosis of dementia was made using the DSM-III-R criteria. The authors also used Markov model to assess the time from Parkinson’s disease, to Parkinson’s disease with dementia, to death.

Of 233 Parkinson’s disease patients, 140 (60%) developed dementia by the end of the 12-year prospective study. At age 70, a man with Parkinson’s disease who develops dementia would be expected to live eight more years, according to the authors. Of these eight years, five would be dementia-free and three would be with dementia. For a 70-year-old woman with Parkinson’s disease, the life expectancy would be 11 years. Of these years, 7.2 years would be expected to be dementia-free and 3.8 would be with dementia.

However, for a Parkinson’s disease patient who already has dementia at 70 years of age, the researchers estimated that the life expectancy would be substantially reduced to 4.2 years for men and 5.7 years for women.

The cumulative incidence of dementia also steadily increases with age and duration of Parkinson’s disease, they noted. Conditional on survival, the cumulative incidence of dementia in Parkinson’s disease patients increases to between 80% and 90% by age 90. Neurology. 2008;70(13):1017-1022.

Adolescents Born Preterm Show Deficits in Cognitive Maturation
NEW YORK, April 14 (Reuters Health)—Very preterm (VPT) birth is associated with decrements of intellectual functioning that persist into adulthood, with deficits in cognitive maturation during adolescence, according to findings published in the April Journal of Neurology, Neurosurgery, and Psychiatry.

“Adolescence is a critical period of brain structural reorganization and maturation of cognitive abilities,” said Dr. Matthew Allin, of King’s College, London, and colleagues.

The researchers conducted neuropsychological evaluations in 94 VPT individuals and 44 term-born subjects at a mean age of 15.3 (adolescence) and 19.5 (young adulthood). VPT birth was defined as birth before 33 weeks’ gestation.

The VPT group had significantly lower full scale, verbal, and performance IQ than the term group at both ages. Paired-sample t-tests showed that verbal IQ decreased in males between adolescence and adulthood but did not change in females. Phonological verbal fluency was also significantly lower in the VPT group at both ages. “Paired-sample t-tests showed that semantic verbal fluency increased significantly in the term group over adolescence, but did not increase in the VPT group,” Dr. Allin’s team reported.

The authors noted that it is not yet clear whether the verbal fluency development of VPT subjects will catch up to that of their peers in time.

J Neurol Neurosurg Psychiatry. 2008;79(4):381-386.

Reuters Health Information: May 2008