Plasma C-peptide levels and rates of cognitive decline in older, community-dwelling women without diabetes

BACKGROUND: Both type 2 diabetes and hyperinsulinemia have been related to diminished cognition. To address independent effects of increasing mid-life insulin secretion on late-life cognition, we prospectively examined the relation of plasma C-peptide levels to cognitive decline in a large sample of older women without diabetes or stroke. METHODS: Plasma C-peptide levels were measured in 1187 "young-old" women (mean age=64 years) without diabetes in the Nurses' Health Study. Cognitive decline was assessed approximately 10 years later. Three repeated cognitive batteries were administered over an average of 4.4 years using telephone-based tests of general cognition, verbal memory, category fluency, and attention. Primary outcomes were general cognition (measured by the Telephone interview for Cognitive Status [TICS], as well as a global score averaging all tests) and a verbal memory score averaging four tests of word-list and paragraph recall. Linear mixed effects models were used to compute associations between C-peptide levels and rates of cognitive decline. RESULTS: Higher C-peptide levels were associated with faster decline in global cognition and verbal memory. Compared to those in the lowest C-peptide quartile, multivariable-adjusted mean differences (95% CI) in rates of decline for women in the highest quartile were -0.03 (-0.06,-0.00) units/year for the global score, and -0.05 (-0.09,-0.02) units/year for verbal memory. Each one standard-deviation increase in C-peptide was associated with significantly faster decline on the TICS (p-trend=0.05), global score (p-trend=0.04) and verbal memory (p-trend=0.006). CONCLUSIONS: Higher levels of insulin secretion in those without diabetes may be related to decline in general cognition and verbal memory.     

Heart rate variability and daytime functioning in insomniacs and normal sleepers: preliminary results

OBJECTIVES: This study examined the differences in heart rate variability (HRV) and daytime functioning between insomniacs and normal sleepers. METHODS: All participants underwent an interview, a medical examination, and a sleep measurement protocol during which they wore an actigraph and logged a sleep diary for a 7-day period to verify their eligibility. Included in the study were 18 insomniacs and 21 normal sleepers. During a laboratory session, these participants completed four paper-pencil tests of sleepiness, anxiety, fatigue, and concentration difficulty and the Wisconsin Card Sorting Test. Resting HRV was recorded under paced breathing. RESULTS: Neither did insomniacs experience cognitive impairment nor did they experience excessive daytime sleepiness compared with normal sleepers. However, insomniacs experienced higher frequency of fatigue [effect size (ES)=1.14, P=.002] compared with normal sleepers. There was also a trend toward higher trait anxiety score (ES=0.62) and concentration difficulty (ES=0.59) in insomniacs than in normal sleepers. Although a tendency toward lower resting high- frequency (HF) HRV (ES=-0.57) in insomniacs than in normal sleepers was noted, neither the resting low-frequency (LF) HRV nor the LF/HF ratio were different between groups. Subjective sleep estimates correlated to self-reported daytime consequences such as fatigue and concentration difficulty but not cognitive function. On the contrary, objective sleep estimates correlated to problem-solving/conceptualization and learning but not self-reported daytime consequences. CONCLUSIONS: Insomniacs are not sleepier during the day than normal sleepers. However, they may experience such a daytime symptom as fatigue although cognitive function remains unimpaired.     

Cortical recruitment during selective attention in multiple sclerosis: an fMRI investigation of individual differences

Recent studies with multiple sclerosis (MS) participants have provided evidence for cortical reorganization. Greater recruitment of task-related areas and additional brain regions are thought to play an adaptive role in the performance of cognitive tasks. In this study, we compared cortical circuitry recruited by MS patients and controls during a selective attention task that requires both focusing attention on task-relevant information and ignoring or inhibiting task-irrelevant information. Despite comparable behavioral performance, MS patients demonstrated increased neural recruitment of task-related areas along with additional activation of the prefrontal cortices. However, this additional activation was associated with poor behavioral performance, thereby providing evidence against compensatory brain reorganization. Future studies specifically investigating the nature of additional activation seen in MS patients in a wider variety of cognitive tasks would provide insight into the specific cognitive decline in MS.     

A cellular mechanism for dendritic spine loss in the pilocarpine model of status epilepticus

Purpose: Previous studies have documented a synaptic translocation of calcineurin (CaN) and increased CaN activity following status epilepticus (SE); however, the cellular effect of these changes in CaN in the pathology of SE remains to be elucidated. This study examined a CaN‐dependent modification of the dendritic cytoskeleton. CaN has been shown to induce dephosphorylation of cofilin, an actin depolymerization factor. The ensuing actin depolymerization can lead to a number of physiological changes that are of interest in SE. Methods: SE was induced by pilocarpine injection, and seizure activity was monitored by video‐EEG. Subcellular fractions were isolated by differential centrifugation. CaN activity was assayed using a paranitrophenol phosphate (pNPP) assay protocol. Cofilin phosphorylation was assessed using phosphocofilin‐specific antibodies. Cofilin–actin binding was determined by coimmunoprecipitation, and actin polymerization was measured using a triton‐solubilization protocol. Spines were visualized using a single‐section rapid Golgi impregnation procedure. Results: The immunoreactivity of phosphocofilin decreased significantly in hippocampal and cortical synaptosomal samples after SE. SE‐induced cofilin dephosphorylation could be partially blocked by the preinjection of CaN inhibitors. Cofilin activation could be further demonstrated by increased actin–cofilin binding and a significant depolymerization of neuronal actin, both of which were also blocked by CaN inhibitors. Finally, we demonstrated a CaN‐dependent loss of dendritic spines histologically. Discussion: The data demonstrate a CaN‐dependent, cellular mechanism through which prolonged seizure activity results in loss of dendritic spines via cofilin activation. Further research into this area may provide useful insights into the pathology of SE and epileptogenic mechanisms.     

Temporal lobe epilepsy does not impair visual perception

Temporal lobe epilepsy (TLE) can impair interictal cognitive function. In the perceptual domain, previous psychophysical studies demonstrated specific deficits in auditory and tactile perception in patients with TLE. This study compared performance of 25 TLE subjects and 27 controls on two low-level, visual tasks: luminance discrimination and frequency discrimination. Both tasks were performed under a relatively easy and a relatively difficult condition, by adjusting the stimulus duration. TLE subjects performed as well as controls on both tasks at both stimulus durations. These results imply that interictal occipital lobe function, as reflected in performance on low-level visual tasks, is not impaired in TLE, consistent with functional imaging data. Furthermore, since TLE subjects performed normally while taking therapeutic doses of multiple AEDs, the data suggest that these AEDs do not impair visual perception.     

Promoting functioning and well-being in older CKD patients: review of recent evidence

Osteoporosis, falls, sleep difficulty, cognitive impairment, and depressed mood are major clinical concerns in the geriatric population that are physiologically and psychologically based and are often interrelated. All of these issues have implications for patients’ daily functioning and quality of life (QOL). This review synthesizes recent evidence about these prominent issues in geriatric care and related implications for care of older patients with chronic kidney disease (CKD). Recent evidence about pre-dialysis and dialysis treatment strategies that may help to optimize management of older patients is also considered. Although elderly patients often report better psychosocial adjustment to dialysis than do younger patients, physical functioning and cognitive functioning losses challenge the QOL of many elderly persons. Early management of CKD and attention to anemia, consideration of the benefits of peritoneal dialysis compared with hemodialysis, and inclusion of some form of exercise or regular physical activity in routine care provide key opportunities to enhance the functioning and well-being of older patients.     

Epilepsy: role of neuropsychological evaluation

Cognitive deficits are frequent in epileptic patients and can be considered epileptic behavioural markers. They are assessed by neuropsychological exploration, which requires the use of standardized psychometric tests. The neuropsychological data obtained complement the information provided by other perisurgical investigations. In addition to the indications concerning lateralization and the extent of the cerebral dysfunction, neuropsychological findings can assist in anticipating the possible cognitive risks resulting from surgical treatment. Finally, these results are indispensable to implementing neuropsychological rehabilitation, which should be proposed before and/or after surgery, when necessary, to patients involved in a surgical program for epilepsy.     

探讨认知—行为干预对行胸腔镜辅助胸骨抬举术患儿的影响

目的:探讨认知—行为干预对胸腔镜辅助胸骨抬举术后患儿的影响。方法:选择40例胸腔镜辅助胸骨抬举术后患儿,随机分为对照组和观察组,对照组给予术后常规护理,观察组给予常规护理的同时实施认知—行为干预,比较两组患儿焦虑及疼痛评分以及对术后康复知识的掌握、住院天数、住院费用情况。结果:两组患儿在焦虑及疼痛评分、住院天数、住院费用及健康知识掌握情况等方面比较均有统计学意义。结论:认知一行为干预能减轻患儿焦虑及疼痛,减少住院天数,降低住院费用,促进患儿快速康复。