晚发性抑郁的生物学机制

晚发性抑郁是指发病年龄大于60岁的一组抑郁综合征,发病机制至今尚不明确。研究表明,晚发性抑郁的遗传因素不明显,而血管损害则与之密切相关;多数患者伴有明显的执行功能损害,痴呆的发病风险增高。围绕晚发性抑郁的两个基本特征:血管损害与认知障碍做一回顾,初步探讨了晚发性抑郁生物学机制对临床决策的影响,并由此展望了未来的研究方向。     

Postoperative Cognitive Dysfunction Versus Complaints: A Discrepancy in Long-Term Findings

This review describes the discrepancy in findings between postoperative cognitive performance and postoperative cognitive complaints long time after an operation under general anesthesia. Shortly (from 6 hr to 1 week) after an operation a decline in cognitive performance is reported in most studies. However, long time (from 3 weeks to 1–2 years) after an operation this is rarely found although some patients are still reporting cognitive complaints. In general this kind of research is suffering from severe methodological problems (use of insensitive tests, lack of control groups, lack of parallel tests, different definitions of cognitive decline). However, these problems cannot totally explain the discrepancy in findings in the long term. Thus, there are patients who have persistent cognitive complaints long time after an operation, that cannot be measured with cognitive tests. More psychological factors such as fixation on short-term cognitive dysfunction, mood, coping style, and personality are possible explanations for these cognitive complaints in the long term. As a consequence, these factors should be a topic in future research elucidating the persistence of these cognitive complaints long time after an operation under general anesthesia.     

Saccade-Stepping Interactions Revise the Motor Plan for Obstacle Avoidance

The authors used a stimulus-response compatibility paradigm to assess the effect of changing the estimated time to obstacle contact. A limb-selection cue was presented in different phases of gait to young (n = 5) and to older (n = 4) adults while they were moving toward a foam obstacle in the walking path. A downward saccade was initiated after the cue; the saccade typically occurred during the stance phase of the target limb (the foot cued to lead the step over the obstacle). The mean saccade-step latency after the cue was on the order of ?500 ms in both young and elderly participants. On reaching the obstacle, both groups generated an upward saccade approximately ?300 ms before target footlift in both groups. Saccades following the limb-selection cue appeared to direct the gaze toward footfall targets just beyond the obstacle, whereas saccades generated just before obstacle footlift moved the gaze to the forward-looking direction. The elderly had significantly longer saccade-trailing-footlift latencies and prolonged gaze-fixation times than did the younger adults. Transient disruptions in optical flow appeared to be necessary for successful obstacle-avoidance behavior when there was an unexpected change in the estimated time to obstacle contact.     

Interacting effects of age and time of day on verbal fluency performance and intraindividual variability

We explored the effects of age and time of day (TOD) on verbal fluency ability with respect to performance level and intraindividual variability (IIV). Verbal fluency, which involves complex cognitive operations, was examined in 20 older (mean age = 72.8 years) and 20 younger (mean age = 24.2 years) adults with test start time alternating between morning and evening across four days. Older adults generated more words in the morning and younger adults more in the evening, corresponding with self-report peak TOD. Age by TOD interactions were also observed across fluency tasks on the number of switches among subcategory exemplars during word generation and on the IIV observed in switching behavior. Older adults exhibited greater variability in switching in the evening than in the morning, whereas younger adults showed the opposite pattern. These findings demonstrate that processes involving energization (initiating and sustaining) and attentional control may be particularly sensitive to age differences in TOD influences on cognition.     

认知老化中有意控制对自动抑制的调节作用

结合比例控制范式与基于空间位置的返回抑制范式, 探讨了认知老化过程中自上而下的有意认知控制对自动抑制的调节作用。结果表明, 当线索有效率由50%提升至80%时, 两组被试的返回抑制量均下降, 老年组表现为返回抑制消失, 但年轻组出现返回抑制的反转, 表明有意认知控制对自动抑制的调节作用受认知老化的影响而发生衰减。同时文章还就认知老化机制的新兴理论—— 执行衰退假说进行了讨论。     

The Behavioral Dyscontrol Scale and Functional Status Among Elderly Medical and Surgical Rehabilitation Patients

This research was conducted in a sample of 150 older adults (mean age = 78.0) who were inpatients receiving rehabilitation services for a variety of medical and postsurgical conditions. The purpose of the study was to test the hypothesis that the Behavioral Dyscontrol Scale (BDS), a measure of the ability to use intentions to guide purposeful activity, would be strongly associated with concurrent functional status after controlling for age, sex, education, severity of pain, medical comorbidity, depression (Geriatric Depression Scale), and general mental status (Mini Mental State Exam [MMSE]). Functional status was assessed by rehabilitaion nurses' ratings of patients on 11 individual Activities of Daily Living (ADL) items and the Barthel Index. The hypothesis, tested by means of multiple regression analysis, was supported by the results. The BDS was the independent variable most strongly associated with all 11 ADL items and the Barthel Index. The MMSE contributed significantly to none of the models. Other covariates made minimal contributions to the variance shared with functional ability. Consistent with prior results in other samples, the ability to use intentions to guide purposeful behavior appears to be an important contributor to everyday functioning among older adults.     

老化刻板印象研究现状及展望

老化刻板印象是人们对老年人所持有的观念与预期,它能显著影响老化刻板印象持有者的生理功能、认知功能和行为结果。现有研究主要集中在老化刻板印象的机制、影响因素和中介变量方面。研究发现,老化刻板印象是通过内化形成的,刻板印象威胁理论和自我刻板化是解释老化刻板印象的两种作用机制。认知加工过程中的抑制能力、情境和文化差异是影响老化刻板印象的主要因素,而老化自我知觉和刻板期望则是老化刻板印象影响效果变量的中介因素。未来研究除了要继续探讨意识水平、情境因素、个体特征对老化刻板印象的影响以及老化刻板印象对不同年龄群体影响的特点以外,还应关注中介和干预研究,并进一步加强跨文化研究。     

Executive cognitive functioning and aggression: Is it an issue of impulsivity?

A large body of research has documented a relation between the executive cognitive functions (ECFs) and interpersonal aggressive behavior. A predominant theory proposes that individuals with poor ECFs are more aggressive because they are unable to inhibit impulsive behaviors. However, evidence for this relationship is typically indirect. In this study, 46 healthy men and women completed measures of ECF, the Taylor Aggression Paradigm, and the Go/No‐Go discrimination task, a behavioral measure of impulsivity. Also, impulsiveness of participant responses during the aggression task was directly assessed by measuring latency of responses to provocation (“set‐time”). It was hypothesized that low‐quartile–scoring ECF men and women would perform more aggressively and more impulsively than high‐quartile peers. Consistent with expectations, results indicated that ECF was related to aggression and to impulsivity on the Go/No‐Go task. However, low‐ECF men and women did not have shorter set‐times; in fact, on this task, low‐ECF participants' behavioral decisions seemed slightly slower than those of high‐ECF participants. In light of these results, the authors speculate that a social information‐processing problem may mediate the ECF aggression relationship rather than altered impulsivity per se. Aggr. Behav. 29:15–30, 2003. © 2003 Wiley‐Liss, Inc.     

Explaining neurocognitive aging: is one factor enough?

As an introduction to the special issue on neurocognitive factors underlying age effects, we discuss a number of recent developments in the literature on aging. The classic distinction between generalized and process-specific cognitive changes with old age has reappeared in the distinctions between the frontal lobe hypothesis and more differentiated views of neurocognitive aging. We argue that neurological decay in the frontal cortex has important implications for cognitive control, but that the frontal lobe hypothesis does not capture the plethora of changes that characterize aging and incorrectly suggests a unitary effect.     

Multigroup Confirmatory Factor Analysis of the Cognitive Dysfunction Questionnaire: Instrument refinement and measurement invariance across age and sex

Vestergren, P., Rönnlund, M., Nyberg, L. & Nilsson, L.‐G. (2012). Multigroup confirmatory factor analysis of the Cognitive Dysfunction Questionnaire: Instrument refinement and measurement invariance across age and sex. Scandinavian Journal of Psychology 53, 390–400. The study adopted Confirmatory Factor Analysis (CFA) to investigate the factorial structure and reduce the number of items of the Cognitive Dysfunction Questionnaire (CDQ). The analyses were based on data for a total of 1,115 participants from population based samples (mean age: 63.0 ± 14.5 years, range: 25–95) randomly split into a refinement (N = 569) and a cross‐validation (N = 546) sample. Equivalence of the measurement and structural portions of the refined model was demonstrated across the refinement and cross‐validation samples. Among competing models the best fitting and parsimonious model had a hierarchical factor structure with five first‐order and one second‐order general factor. For the final version of the CDQ, 20 items within five domains were selected (Procedural actions, Semantic word knowledge, Face recognition, Temporal orientation, and Spatial navigation). Internal consistency reliabilities were adequate for the total scale and for the subscales. Multigroup CFAs indicated measurement invariance across age and sex up to the scalar level. Finally, higher levels of cognitive dysfunction as reflected by CDQ scores were predicted by advancing age, fewer years of education, and with deficits in general cognitive functioning as reflected by scores on the Mini‐Mental State Examination. In conclusion, the CDQ appears to be psychometrically sound and shows the expected relationships with variables known to be associated with cognitive dysfunction and dementia. Future studies should apply it among clinical groups to further test its usefulness.     

Age and Cognitive Stress Influences Motor Skill Acquisition,Consolidation, and Dual-Task Effect in Humans

This study examined motor skill learning using a weight-bearing and cognitive-motor dual-task that incorporated unexpected perturbations and measurements of cognitive function. Forty young and 24 older adults performed a single-limb weight bearing task with novel speed, resistance, and cognitive dual task conditions to assess motor skill acquisition, retention and transfer. Subjects performed a cognitive dual task: summing letters in one color/orientation (simple) or two colors/orientations (complex). Increased cognitive load diminished the rate of skill acquisition, decreased transfer to new conditions, and increased error rate during an unexpected perturbation; however, young adults had a dual-task benefit from cognitive load. Executive function predicted 80% of the variability in dual-task performance. Although initial learning of a weight-bearing cognitive-motor dual-task was poor, longer term goals of improved dual-task effect and retention emerged.     

The Development of Attribute Dominance in the Knowledge Base

Two cuing, free-recall studies were conducted to test Bach and Underwood's (1970) hypothesis that acoustic encoding is dominant among second graders and semantic encoding is dominant among sixth graders. When retrieval cues were presented with to-be-remembered items at both input and output (Experiment 1), and when cues were presented only at output (Experiment 2), semantic cues were more efficient in elevating recall than were acoustic cues for both second and sixth graders. When these and other results generally found using recognition, sorting, incidental learning, and free-recall experimental designs are compared, it seems plausible that item presentation and memory-testing formats interact with age, and that these factors account for the different patterns of attribute dominance found in the literature. The knowledge base cannot be understood by focusing on either subject or task analyses, but only by focusing on interactions between subject and task variables as they change over time. The educational implications for young grade-school children are discussed.