Carla Ruis

Cognitive dysfunction in patients with type 2 diabetes.

People with diabetes mellitus are at increased risk of cognitive dysfunction and dementia. This review explores the nature and severity of cognitive changes in patients with type 2 diabetes. Possible risk factors such as hypo‐ and hyperglycemia, vascular risk factors, micro‐ and macrovascular complications, depression and genetic factors will be examined, as well as findings from brain imaging and autopsy studies. We will show that type 2 diabetes is associated with modest cognitive decrements in non‐demented patients that evolve only slowly over time, but also with an increased risk of more severe cognitive deficits and dementia. There is a dissociation between these two ‘types’ of cognitive dysfunction with regard to affected age groups and course of development. Therefore, we hypothesize that the mild and severe cognitive deficits observed in patients with type 2 diabetes reflect separate processes, possibly with different risk factors and aetiologies. Copyright

The Backward Span of the Corsi Block-Tapping Task and Its Association With the WAIS-III Digit Span

The Corsi Block-Tapping Task measures visuospatial short-term and working memory, but a standardized backward condition is lacking. The authors present a standardized backward procedure that was examined in 246 healthy older adults (ages 50 to 92), comparing the results with the Digit Span subtest of the Wechsler Adult Intelligence Scale— Third Edition. Principal component analysis resulted in a two-factor model, dissociating a verbal and a spatial working-memory factor. Also the Corsi backward is not more difficult than the Corsi forward, in contrast to the Digit Span backward that is more difficult than the Digit Span forward. This may suggest that the Corsi Block-Tapping Task backward task relies on processing within working-memorys slave systems, whereas the Digit Span backward also relies on the central executive component of working memory. Finally, regression-based normative data and cutoff scores for older adults are presented for use in clinical practice.

Cognition in the Early Stage of Type 2 Diabetes

OBJECTIVE Type 2 diabetes is known to be associated with decrements in memory and executive functions and information-processing speed. It is less clear, however, at which stage of diabetes these cognitive decrements develop and how they progress over time. In this study, we investigated cognitive functioning of patients with recent screen-detected type 2 diabetes, thus providing insight into the nature and severity of cognitive decrements in the early stage of the disease. Possible risk factors were also addressed. RESEARCH DESIGN AND METHODS Included in this study were 183 diabetic patients from a previously established study cohort and 69 control subjects. A full neuropsychological assessment, addressing six cognitive domains, was made for each participant. Raw test scores were standardized into z scores per domain and compared between the groups. Possible risk factors for cognitive decrements were examined with multivariate linear regression. RESULTS Relative to scores for the control group, mean z scores were between 0.01 and 0.2 lower in the diabetic group across all domains, but after adjustment for differences in IQ between patients and control subjects, only memory performance was significantly reduced (mean difference −0.15 [95% CI −0.28 to −0.03]). A history of macrovascular disease and current smoking were significant determinants of slower information-processing speed in patients with diabetes. CONCLUSIONS This study shows that modest cognitive decrements are already present at the early stage of type 2 diabetes. A history of macrovascular disease and smoking are significant risk factors for some early decrements.

Intensive multifactorial treatment and cognitive functioning in screen-detected type 2 diabetes — The ADDITION-Netherlands study: A cluster-randomized trial

AIM To assess whether an intensive multifactorial treatment can reduce cognitive decrements and cognitive decline in screen-detected type 2 diabetes. METHODS The multinational ADDITION-study, a cluster-randomized parallel group trial in patients with screen-detected type 2 diabetes, compared the effectiveness of intensive multifactorial treatment (IT; lifestyle advice and strict regulation of metabolic parameters) with routine care (RC) on cardiovascular outcome. In The Netherlands randomization was stratified according to practice organization. Allocation was concealed from patients. The present study assessed the effect of IT on cognition through two neuropsychological assessments (NPA) on two occasions. The assessments took place three and six years after the start of the intervention. Non-diabetic controls served as reference group. The first NPA was performed in 183 patients (IT: 97; RC: 86) and 69 controls. The second NPA was performed in 135 patients (IT: 71; RC: 64) and 55 controls. Primary outcome was a composite score, including the domains memory, information-processing speed and attention and executive function. Comparisons between the treatment groups were performed with multi-level analyses. RESULTS The first NPA showed no differences between the treatment groups (mean difference composite z-score: 0.00; 95%-CI -0.16 to 0.16; IT vs RC). Over the next three years cognitive decline in the diabetic groups was within the range of the reference group and did not differ between the treatment arms (difference decline between diabetic groups -0.12; -0.24 to 0.01; IT vs RC). CONCLUSIONS Six years of IT in screen-detected type 2 diabetes had no benefit on cognitive functioning over RC.

Effects of errorless and errorful face-name associative learning in moderate to severe dementia

Background and aims: The prevention of errors during learning has been found to be effective in overcoming memory problems in patients with amnesia compared with errorful or trial-and-error learning, possibly as a result of intact implicit memory function. Although errorless learning is a clinically promising technique used in cognitive training settings, to date only a few studies have examined errorless learning in patients with dementia. Methods: The current study examined errorless and errorful learning using a face-name associative memory task in a group of moderate to severe dementia patients suffering from probable Alzheimer’s disease (MMSE≤22; n = 10) using a fully counterbalanced within-subject design. Results: Errorless learning had a significantly beneficial effect after two consecutive learning trials (p=0.01). However, after an unfilled delay of 10 minutes, no significant differences in memory performance were found between errorless and errorful learning. Furthermore, current effects were much smaller compared with previous findings in healthy adults and early-stage dementia patients. Conclusions: Although errorful learning resulted in better performance in a face-name associative memory task in patients with dementia, this effect was only short-lived. Thus, the beneficial effects of errorless learning are probably not due to intact implicit memory function, but may also be subserved by explicit memory, a memory system that is typically impaired in dementia. Also, the clinical applicability of errorless learning in teaching patients with moderate to severe dementia face-name associations is limited.

The Brixton Spatial Anticipation Test as a test for executive function: validity in patient groups and norms for older adults.

Impairments in executive functioning frequently occur after acquired brain damage, in psychiatric disorders, and in relation to aging. The Brixton Spatial Anticipation Test is a relatively new measure for assessing the ability to detect and follow a rule, an important aspect of executive functioning. To date, normative data on this task are limited, particularly concerning the elderly. This study presents age- and education-adjusted regression-based norms obtained in a group of healthy older participants (n = 283; mean age 67.4 +/- 8.5 years). The applicability and validity of these norms were further examined in different groups of patients with stroke (n = 106), diabetes mellitus (n = 376), MCI/early dementia (n = 70), psychiatric disorders (n = 63), and Korsakoffs syndrome (n = 41). The results showed that patients with Korsakoffs syndrome, stroke, and psychiatric disorders performed significantly worse than healthy controls. Test-retest correlation (n = 83), learning effects, and correlations with other neuropsychological tests were also explored. Based on the present study, the Brixton test appears a useful addition to existing measures of executive functioning. Moreover, the test can be reliably applied in different groups of clinical patients.

The Telephone Interview for Cognitive Status (Modified): Relation with a comprehensive neuropsychological assessment

The modified Telephone Interview for Cognitive Status (TICS-m) is a widely used screening instrument for (Alzheimers) dementia. Psychometric evaluation of the TICS-m is limited. This study examined the relation between the TICS-m and a comprehensive neuropsychological assessment in older persons (n = 243) without cognitive deficits. The TICS-m total score correlated with multiple cognitive domains (range r = .22–.49). Factor analysis of the TICS-m items yielded four interpretable factors: “verbal memory,” “orientation/mental tracking,” “language/reasoning,” and “attention/working memory,” which also showed (modest) correlations with the neuropsychological assessment (r = .02–.48). The TICS-m appears to reflect a “general cognitive ability” rather than, for example, memory functioning alone.

The role of Funktionswandel in metamorphopsia

Patients with metamorphopsia perceive objects or faces as being distorted and/or different in size. In most cases, recognition is not impaired. The stimulus specificity, particularly in the case of face perception, has led to the suggestion that metamorphopsia is a deficit at the entry level of category-specific recognition systems; in this case, the face processing system. An explanation in terms of a visuosensory deficit (i.e., Funktionswandel) that affects the perception of specific stimulus categories has not been systematically evaluated. In this study, we report two patients (MZ and CM) who experienced hemi-metamorphopsia for faces after a stroke in the posterior part of the brain. Despite the distortions, they could still match and recognize faces. We carried out a detailed evaluation of their visual-sensory status and found that both MZ and CM had specific problems with discriminating and estimating sizes and shapes, especially in the contralesional visual field. It was concluded that these cases, metamorphopsia was not due to a higher-order perception impairment specific for faces, but rather of a specific impairment in shape perception in the contralesional visual field that proportionally affects the perception of faces.

Mild depressive symptoms do not influence cognitive functioning in patients with type 2 diabetes

Type 2 diabetes (T2DM) is associated both with cognitive decrements and depressive symptoms. Since depression in itself has been associated with cognitive decrements we aimed to investigate the influence of depressive symptoms on the relation between T2DM and cognitive functioning. Data were derived from three independent studies on cognitive functioning in patients with T2DM (n=366) and controls without diabetes (n=204), two with longitudinal and one with only cross-sectional assessments. Depressive symptoms were measured with self-report inventories (CES-D or BDI-II). The composite z-score of the domains memory, information-processing speed, and attention and executive function was the primary cognitive outcome measure. Mixed linear regression analyses were used in a stepped approach to compare cognitive functioning between (1) patients with T2DM and controls (cross-sectionally and longitudinally), (2) participants with and without depressive symptoms, separately for patients and controls, and (3) patients and controls after adjustment for depressive symptoms. In addition the mediating effect of depressive symptoms was assessed with a bootstrapping technique. Depressive symptoms were present in 11% of the patients with T2DM and in 7% of controls (p=0.15). Cognitive performance in patients with T2DM was worse than in controls (overall difference composite z-score -0.13). However, T2DM was not associated with accelerated cognitive decline over three years of follow-up relative to controls. Controls with depressive symptoms performed worse than those without depressive symptoms, although not statistically significant. Performance in patients with T2DM with and without depressive symptoms was similar. Adjustment for depressive symptoms and estimation of the mediating effect showed that the difference between patients and controls was not mediated by depressive symptoms. In conclusion, the modest cognitive decrements that are associated with T2DM are not due to the presence of mild depressive symptoms.

The impact of self-reported depressive symptoms on memory function in neurological outpatients

OBJECTIVES To examine the effect of self-reported depressive symptoms on memory function in a non-psychiatric, non-litigation outpatient sample and to identify which memory tests may be most susceptible for depression-related decline. METHODS Self-reported depressive symptoms were measured by the Beck Depression Inventory (BDI-II) and memory function was assessed using a wide range of neuropsychological memory tests (digit span, word-list learning, visuospatial learning, incidental memory, story recall). Patients who visited the neurological outpatients clinic and were referred for a neuropsychological examination were included (N=50). RESULTS Correlation analyses showed that the BDI-II was significantly correlated with immediate story recall, delayed verbal recognition and the digit span. Furthermore, patients with mild or moderate-to-severe depressive symptoms performed worse than non-depressed patients on immediate story recall, but not on any of the other memory tests. DISCUSSION Memory performance is only minimally disrupted in neurological outpatients with depressive symptoms compared to non-depressed outpatients. These results are discussed in relation to limited mental effort and weak encoding in patients with self-reported depressive symptoms.