Research into smoking or nicotine and human cognitive performance: does the source of funding make a difference?

AIMS: To establish whether there is a relationship between tobacco industry support of basic research and the conclusions drawn by the authors of that research. DESIGN: A sample of 91 papers investigating the effects of tobacco or nicotine use upon cognitive performance was analyzed to see if the pattern of conclusions drawn by researchers acknowledging tobacco industry support differed from the pattern of conclusions drawn by researchers not acknowledging tobacco industry support. FINDINGS: Scientists acknowledging tobacco industry support reported typically that nicotine or smoking improved cognitive performance while researchers not reporting the financial support of the tobacco industry were more nearly split on their conclusions. CONCLUSIONS: While it is only possible to speculate on the possible reasons, the existence of a possible bias in the published literature according to funding source must be given serious consideration.

Pyritinol treatment of SDAT patients: evaluation by psychiatric and neurological examination, psychometric testing and rCBF measurements.

A group of 26 patients with the diagnosis of Senile Dementia of Alzheimer type (SDAT) was included by random assignment in a double-blind, cross-over trial of pyritinol versus placebo. The patients had a mild to moderate degree of dementia. Psychiatric and neurological examination, psychometric testing, and measurement of the regional cerebral blood flow (rCBF) at rest and during mental activation were used to assess treatment effects. The results of the study showed that pyritinol was associated with a significant improvement in cognitive performance. RCBF data showed that treatment with pyritinol normalized the pattern of blood flow increase during activation and improved the score on the test used for activation.

Effects of occupational exposure to organic solvents upon cognitive performance.

Twenty-three individuals exposed to mixed organic solvents were compared with 23 nonexposed controls on a number of cognitive performance tasks. Solvent exposure resulted in a significantly poorer performance on the forward digit span test, copying of a complex figure, and on semantic memory tests which also measure individual's ability to integrate linguistic information into cohesive units. These tasks rely heavily upon short-term memory and its integrative operations in higher cognitive function. Acute exposure effect was also observed for the linguistic integrative task.

Implications of cognitive change for gerontological pedagogical practice.

The focus of this paper is the problem of designing educational systems for the aged so as to maximize their potential for success. Relevant geropsychological literature is briefly summarized. It is proposed that complex changes in working memory occur with advanced age; and that by understanding the nature of these changes, educational materials can be designed which properly bring to the fore concepts, refresh memory, and guide the comprehension process. In this way, the aged are more likely to maintain their performance and to acquire new skills, to the benefit of society.

Contextual effects upon text memory for young, aged-normal, and aged memory-impaired individuals.

The purpose of the study was to assess contextual effects upon text memory for young, aged-normal, and aged memory-impaired individuals. Subjects read short passages which differed in their contextual relatedness to target sentences, and then recalled those target sentences. It was found that large differences distinguished the performance of the young from the elderly on the free recall task; that cueing aided the performance of the young and the elderly-normal more than the aged-impaired; and lastly, that no differences were found in recognition performance between young and aged normals whereas the performance of the aged-impaireds was significantly poorer than either the young or the aged-normal group. The results were interpreted in light of two hypothetical mechanisms; the first is labeled "normal" aging and the second, "pathological" aging.

Some important methodological issues in the study of aging and cognition.

Despite extensive geropsychological research into cognitive change with advanced age, there is conflicting evidence regarding the nature of this change and even well developed arguments that no decrement with advanced age exists. A review of the field suggests that researchers have neglected certain important parameters which might greatly affect results Specifically, the following topics are examined: (1) determination as to what constitutes "young" and "old", (2) the source of the subjects in aging research, (3) methods of matching subject groups and (4) considerations of group heterogeneity. It was concluded that these issues are often confounded within research designs, that controlling them would help clarify theoretical issues, and that these parameters, when controlled, are themselves worthy of interest.

Contextual effects upon text memory for young, aged-normal, and aged memory-impaired individuals.

The purpose of the study was to assess contextual effects upon text memory for young, aged-normal, and aged memory-impaired individuals. Subjects read short passages which differed in their contextual relatedness to target sentences, and then recalled those target sentences. It was found that large differences distinguished the performance of the young from the elderly on the free recall task; that cueing aided the performance of the young and the elderly-normal more than the aged-impaired; and lastly, that no differences were found in recognition performance between young and aged normals whereas the performance of the aged-impaireds was significantly poorer than either the young or the aged-normal group. The results were interpreted in light of two hypothetical mechanisms; the first is labeled "normal" aging and the second, "pathological" aging.

Cigarette smoking and cognitive performance.

While some investigations into the relationship between smoking and cognitive performance have reported that smoking facilitates performance, other research has come to the opposite conclusion. A review of the literature suggests that this variance in results may be due to differences among studies in design (comparing smokers only with deprived smokers rather than with non-smokers) and also to differences in task demands. Therefore, performance of smokers having just smoked, matched smokers deprived for a brief period, and also non-smokers was contrasted on a series of tasks which ranged from repetitive and perceptually-bound tasks to complex, dynamic tasks dependent upon long-term memory. It was found that while cigarette smoking had no negative effect upon performance for simple perceptual tasks, smoking was found to exert measurable negative effects upon performance for more complex information processing tasks.

Changes in short-term memory processes in patients with multiple sclerosis.

In this study we compared the performance of 39 multiple sclerosis (MS) patients with 28 age-, sex- and education-matched controls on both the Mini-Mental State Examination, a global cognitive assessment tool, and the Sternberg Short-Term memory scanning task, a standardized test of short-term memory (STM) processes. While the STM span of our MS patients did not differ from that of our controls, STM scanning time of the MS group was reliably slower than that of the controls and a significant correlation was observed between STM scanning time and duration but not severity of illness. Our results suggest that processing stages other than the manipulation of data within the STM buffer are also affected by MS.