[Validation of an Icelandic version of the Geriatric Depression Scale (GDS).].

OBJECTIVE: The GDS is a widely used tool world wide, both in clinical practice and in research of the elderly. The objective was to translate and validate the Geriatric Depression Scale (GDS) in Iceland. The short version of the GDS was also studied. MATERIAL AND METHODS: GDS was translated from English to Icelandic and backtranslated. Individuals, both hospitalised and healthy, born 1933 or before were included in the study. Those who had MMSE (Mini Mental State Examination) score under 23 were excluded. Seventy-one individuals were examined for depression both with a structured interview, Composite International Diagnostic Interview; 1993 (CIDI-a) and with the GDS. RESULTS: The GDS results were comparable to the results from the interview. The cutoff score for depression was chosen 13/14 according to the most favorable values of sensitivity (0.77), specificity (0.95), positive predictive value (0.77) and kappa (0.72). One cutoff was chosen because in our study there were persons with moderate or severe depression but no one with mild depression was detected. Our cutoff score for depression was identical with the cutoff score in the original american GDS version, but the original american version included a cutoff for mild depression also. CONCLUSIONS: The Icelandic GDS is a reliable method to screen for depression among the elderly. We conclude that GDS is an useful tool in unravelling depressive illness amongst the elderly although not diagnostic per se.

[Epidemiological study on cognitive abilities in the elderly in two separate rural areas in Iceland.].

OBJECTIVES: This study was undertaken to estimate the cognitive abilities in an elderly population in rural areas in Iceland and to get an idea of the prevalence of dementia. By examining inhabitants in two different areas it was further possible to detect any possible difference in these areas. MATERIAL AND METHODS: All persons aged 70 and over, living independently in the community and in institutions in two geographically separate areas were contacted. The areas were an agricultural (area A) and a fishing (area F) one. Four simple neuropsychological tests where used, the MMSE (Mini Mental State Examination), WAIS (Wechsler Adult Intelligence Scale)-Similarities, Trail making test A and Trail making test B. Two students in psychology and a teacher were trained in applying the tests but the results were scored and interpreted by the authors. RESULTS: In area A, 280 of 353 (79.3%) participated and in area F, 190 of 238 (79.8%). Participation was thus similar in both areas. There was a highly significant difference in all the tests with p<0.01 in Trail making test B but p<0.001 in the other three tests. In all the tests the results were better among the population in area A. The prevalence of dementia as estimated by the MMSE showed a prevalence of 14.4% in area A and 35.7% in area F. CONCLUSION: A significant difference in cognitive abilities was found between the elderly inhabitants of two separate rural areas in Iceland. There is substantial evidence to suggest that this difference is real but it is however not clear if the prevalence of dementia is higher in this study than in others. It is postulated that the difference found is due to cultural differences.

The effects of nicotine in dermal plaster on cognitive functions in patients with Alzheimer's disease.

Eighteen patients with probable Alzheimer's disease (NINCDS/ADRDA criteria) participated in a placebo-controlled, double-blind study, with a crossover design. The patients had mild or moderate dementia (MMSE = 20.3 +/- 4.6, range 12-28). The trial consisted of two 4-week periods with a 2-week washout period in between. Nicotine was given in the form of dermal plasters. Most of the patients tolerated the highest doses of 21 mg nicotine/24 h, but some received 14 mg/24 h. The effect was monitored with tests of short-term memory, verbal fluency, attention and psychomotor speed. Nicotine was also determined in the blood. Short-term memory improved significantly after 4 weeks of treatment, both on nicotine and placebo (p < 0.05/p < 0.01). The results of our study thus do not indicate that nicotine applied in the form of dermal plasters is of any significance in the treatment of memory deficits in patient with Alzheimer's disease.

A progression in the neuropsychological decline of Icelandic patients with probable or possible dementia of the Alzheimer's type: a longitudinal study.

To investigate the nature and rate of cognitive decline in dementia of the Alzheimer's type (DAT), 44 patients with probable or possible DAT (mean age 73.9, range 59-87 years) were given a comprehensive neuropsychological assessment. Twenty-five patients were retested 6 months later, and 11 were tested for the third time another 6 months later. Some tests of mental flexibility and double conceptual tracking ability were beyond the capabilities of the patients, and were left out of the statistical analysis because of floor effect. Poor initial performance on tests of attention, concentration, response speed, general cognitive ability, verbal memory, constructional skills, and perceptual closure ability resulted in nonsignificant changes over time (paired t tests). Tests of expressive speech, visuoperceptual functions and nonverbal memory, on the other hand, showed a significant deterioration over time. These findings indicate that when patients with DAT first receive medical attention, many neuropsychological functions are so severe impaired that there is little room for further decline. To describe the longitudinal course of cognitive decline in DAT, tests should be limited to those that assess the more resistant cerebral functions, and are more sensitive to progressive changes.

Processing from LVF, RVF and BILATERAL presentations: examinations of metacontrol and interhemispheric interaction.

Observers indicated whether two successively presented drawings of faces were identical or differed in one feature (hair, eyes, mouth, jaw). The first face of each pair was presented at the fixation point and the second was presented to the left visual field-right hemisphere (LVF-RH), right visual field-left hemisphere (RVF-LH), or to both visual fields simultaneously (BILATERAL). On DIFFERENT trials the RT of correct responses depended on which feature differed and the pattern of feature location effects was significantly different on LVF-RH and RVF-LH trials. On BILATERAL trials the feature location effect was identical to that obtained on RVF-LH trials and significantly different from that obtained on LVF-RH trials. In addition, the percentage of errors and RT of correct responses were both higher on BILATERAL trials than on unilateral trials. Implications of these results are considered for the concept of "metacontrol" in neurologically normal humans and for models of interhemispheric interaction.

Lateralized effects of blurring: a test of the visual spatial frequency model of cerebral hemisphere asymmetry.

In a Physical Identity letter comparison task, blurring the stimuli impaired performance when stimuli were projected to the right visual field but not when stimuli were projected to the left visual field. Whether this effect was obtained for response accuracy or for reaction time of correct responses depended on whether the stimuli were difficult or easy to classify. In two experiments it is shown that when the classification task is so difficult that the error rates are high, the Stimulus Clarity x Visual Field interaction is restricted to response accuracy measures. When the classification task is so easy that the error rates are low in all conditions, the critical interaction is restricted to reaction time of correct responses. The results are consistent with the hypothesis that the left and right hemispheres are biased toward efficient processing of higher and lower ranges of visual spatial frequency, respectively.

Effects of perceptual quality on the processing of human faces presented to the left and right cerebral hemispheres.

Three experiments examined the effects of stimulus duration, retinal eccentricity, and visual noise on the processing of human faces presented to the left visual field/right hemisphere (LVF-RH) and right visual field/left hemisphere (RVF-LH). In Experiment 1 observers identified which of 10 similar male faces was presented on a screen. The single face was presented for 10, 55, or 100 ms at 1 degree, 4 degrees, or 9 degrees of visual angle to the left or right of fixation. Decreasing stimulus duration and increasing retinal eccentricity lowered face recognition. The effect of duration was the same for LVF-RH and RVF-LH trials, but the detrimental effect of increasing retinal eccentricity was larger on LVF-RH trials than on RVF-LH trials. In Experiment 2 observers indicated whether a single face from this same set was a member of a memorized set of five positive faces. The probe face on each trial was presented alone or embedded in visual noise. Visual noise increased the error rate more on LVF-RH trials than on RVF-LH trials. This effect was replicated in Experiment 3, which also required observers to make a much easier discrimination between male and female faces. In the male/female task visual noise tended to impair performance more on RVF-LH trials than on LVF-RH trials, opposite the effect for the male/male task. These results are discussed in terms of hemispheric asymmetry for global versus local features of faces, the level of feature analysis demanded by a task, and the level of feature analysis most disrupted by perceptual degradation.