Biomedical subjects

Maria Tsiakas

Publications and source records attributed to Maria Tsiakas.

4 recordsLinked to original sources

PubMed2004

Explicit and objective scoring criteria for the taylor complex figure test.

The Rey and Taylor figures are two constructional and visual memory tests used interchangeably. The purpose of this study was to develop a scoring system for the Taylor figure based on the explicit guidelines established by Meyers and Meyers (1995) for the Rey figure. Younger (n = 97; mean age = 21 years) and older (n = 61; mean age = 72 years) participants' performance on the Taylor figure was scored according to the proposed scoring system and the original scoring system devised by Taylor (1989). Both scoring systems yielded comparable scores on the Taylor figure as well as comparable patterns of validity and good interrater reliabilities (0.85-0.98). Although the present system does not further improve scoring reliability, it renders both tests similar in methodology and simplifies training to evaluate the two figures. The present study also reveals the limitations of the use of the Taylor and the Rey in test-retest situations but suggests that administering the Taylor first would improve the comparability of the two figures in a test-retest situation.

Adult↗

PubMed2004

Addressing the differences in speed of processing of the intervening calculation task on the modified Brown-Peterson task.

The Modified Brown-Peterson task (MBPT) is a task of divided attention and working memory that requires central executive functioning. It is a variant of the Brown-Peterson technique and is useful for studying short-term retention of information. It involves the recall of auditory information under conditions of interference (i.e., counting backwards). Previous research has not addressed the effect of individual differences in processing speed for the intervening calculations. In a sample of 81 young participants, we determined whether the number of correct calculations performed is related to recall performance on the MBPT. Results indicated that the number of calculations performed was not significantly related to the recall performance on the MBPT. Rather, the number of correct calculations performed during the interference task of the MBPT was associated with arithmetic ability as measured by the arithmetic subtest of the Adult Intelligence Scale-III (Wechsler, 1997). These results suggest that the subtractions in the MBPT create interference regardless of mathematical ability or speed at which the subtractions are performed during the interference condition of the MBPT task. This observation suggests that the results on this test are independent of mathematical ability and represent a useful measure of working memory.

Adult↗

PubMed2003

Effect of age and glucoregulation on cognitive performance.

Non-insulin dependent diabetes mellitus (NIDDM) has been associated with a number of physiological consequences including neuropathy, retinopathy and incidence of vascular disease. Recently, several authors reviewed studies that suggested that NIDDM is associated with cognitive impairments leading to a higher incidence of dementia. In the present experiment, we measured cognitive function in 57 healthy male and female non-diabetic older participants who ranged in age from 55 to 84. Various biological measures were obtained including a glucose tolerance test during which glucose and insulin were measured. Participants were separated into better and poorer glucoregulatory groups on the basis of their blood glucose levels during the tolerance test. Participants were evaluated twice, once after drinking a saccharin solution and on another occasion after drinking a glucose solution (50 g). Older participants (72 years and over) with poorer glucoregulation had the worse performance in tests evaluating working memory, verbal declarative memory and executive functions. Glucose administration appeared to only attenuate the decrements observed in the saccharin condition in the older participants for some of the tests. These results suggest that cognitive functions may be impaired before glucoregulatory impairment reaches levels consistent with a type II diabetes diagnosis.

Age Factors↗

PubMed2002

Impact of peripheral glucoregulation on memory.

Impaired glucoregulation is associated with neuropsychological deficits, particularly for tests that measure verbal declarative memory performance in older diabetic patients. The performances of 74 undergraduate students (mean age = 21 years) on several verbal declarative measures, including immediate and delayed paragraph recall, verbal free recall, and order reconstruction tasks, were correlated with glucoregulatory indices. The indices were obtained from glucose and insulin levels after a 75-g glucose load. In general, higher blood glucose levels were associated with poorer performance on all memory tests. Glucose ingestion did not interact with performance except on the most difficult task. Subjects with poorer glucoregulation showed higher evoked glucose and insulin, suggestive of a mild glucose intolerance accompanied by mild insulin insensitivity. Results suggest that poor peripheral glucoregulation has an impact on central nervous system functions.

Adult↗