The effects of docosahexaenoic acid supplementation on cognition and well-being in mild cognitive impairment: A 12-month randomised controlled trial.

OBJECTIVES: Several recent clinical trials have shown that docosahexaenoic acid (DHA) supplements have a significant effect on cognition in cognitively impaired older adults. This randomised controlled trial aimed to investigate the cognitive effects of a DHA fish oil supplement in older adults with mild cognitive impairment, and to examine the moderating effect of the apolipoprotein E (APOE) ɛ4 allele on cognition and well-being. METHODS/DESIGN: Seventy-two older adults between the ages of 60 and 90 from New Zealand were given a DHA supplement equivalent to 1491 mg DHA + 351 mg eicosapentaenoic acid per day or a placebo for a period of 12 months. Outcome measures included cognition, wellbeing and self-rated quality of life as well as height, weight, blood pressure and APOE genotyping. RESULTS: The final analysis (n = 60) found no evidence of a treatment effect on cognitive measures, although did find a treatment effect on systolic blood pressure (p = 0.03, ƞ2  = 0.08), and a treatment interaction for APOE ɛ4 carriers on depression (p = 0.04, ƞ2  = 0.07) and anxiety (p = 0.02, ƞ2  = 0.09) scores in favour of the DHA supplement. CONCLUSIONS: Despite no effect on cognition, the positive result in APOE ɛ4 carriers on depression and anxiety scores and on systolic blood pressure justifies further DHA trials. It may be a prudent step going forward for more studies to replicate the design elements (dose, duration and cognitive measures) of previous DHA trials to help understand why not all older adults appear to benefit from taking a fish oil supplement.

Conceptualization of the complex outcomes of sexual abuse: a signal detection analysis.

Eighty-five New Zealand based practitioners experienced in treating adults with a history of child sexual abuse participated in an online judgment study of child sexual abuse outcomes using signal detection theory methodology. Participants' level of sensitivity was assessed independent of their degree of response bias when discriminating (a) known child sexual abuse outcomes from behaviors thought to be unrelated to child sexual abuse and (b) direct child sexual abuse effects from subsequent coping strategies. Results demonstrated good sensitivity (accuracy) when identifying child sexual abuse effects from noneffects. When asked to discriminate direct child sexual abuse effects from ways of coping with distress, practitioners' accuracy was reduced, revealing a tendency to identify all effects as coping. Although treatment approaches highlight the pivotal role of identifying coping strategies, practitioners did not perceive maladaptive coping as a distinct clinical feature. Complex abuse cases may benefit from replacing maladaptive coping strategies (e.g., self-harm) with constructive coping (e.g., social support) in order to deliver efficacious practice.

Driving fear and driving skills: comparison between fearful and control samples using standardised on-road assessment.

The present study explores driving skills in a group of 50 media-recruited driving-fearful and 50 control drivers, all of whom were women. Participants completed an on-road practical driving assessment with a professional driving instructor. Diagnostic as well as pre-post self-report and instructor driving assessments were conducted. Fearful drivers made more errors on the driving assessment than controls. However, the pattern of errors was identical for both groups, indicating that fear and anxiety may be associated with the number rather than the type of driving errors made. These differences remained when factors such as driving history, current driving frequency, and diagnosis were controlled using case selection. More research is needed to replicate the findings in more diverse samples. Additional work should also aim to clarify the specific role of driving skills in driving fear, which will facilitate treatment planning for exposure-based treatments and help identify cases where driving skills assessment may be appropriate.

The Driving Cognitions Questionnaire: development and preliminary psychometric properties.

Recent research has suggested that fear of driving is common in the general population. People may have various concerns when driving, and instruments for the assessment of these concerns are lacking. The present paper describes the development and preliminary evaluation of the Driving Cognitions Questionnaire (DCQ). The DCQ is a 20-item scale that measures three areas of driving-related concerns--panic-related, accident-related, and social concerns. In three separate samples from different countries (n=69, 100, and 78), the scale showed good internal consistency and substantial correlations with measures of the severity of driving fear. It discriminated well between people with and without driving phobia. It also showed convergent validity with other measures. The questionnaire shows promise for use in research and clinical practice.

Kiwifruit Non-Sugar Components Reduce Glycaemic Response to Co-Ingested Cereal in Humans.

Kiwifruit (KF) effects on the human glycaemic response to co-ingested wheat cereal were determined. Participants (n = 20) consumed four meals in random order, all being made to 40 g of the same available carbohydrate, by adding kiwifruit sugars (KF sug; glucose, fructose, sucrose 2:2:1) to meals not containing KF. The meals were flaked wheat biscuit (WB)+KFsug, WB+KF, WB+guar gum+KFsug, WB+guar gum+KF, that was ingested after fasting overnight. Blood glucose was monitored 3 h and hunger measured at 180 min post-meal using a visual analogue scale. KF and guar reduced postprandial blood glucose response amplitude, and prevented subsequent hypoglycaemia that occurred with WB+KFsug. The area between the blood glucose response curve and baseline from 0 to 180 min was not significantly different between meals, 0-120 min areas were significantly reduced by KF and/or guar. Area from 120 to 180 min was positive for KF, guar, and KF+guar, while the area for the WB meal was negative. Hunger at 180 min was significantly reduced by KF and/or guar when compared with WB. We conclude that KF components other than available carbohydrate may improve the glycaemic response profile to co-ingested cereal food.

Understanding Guillain-Barré syndrome and central nervous system involvement.

Guillain-Barré syndrome is a rare neurological disease that causes paralysis and may necessitate hospitalization for some patients in its acute stages. It primarily affects the peripheral nervous system, though recent research has shown that for some patients, the central nervous system is involved. The acute phase often requires intensive care services. Recognition is growing that recovery is not as smooth and free of symptoms as previously thought. Following "recovery" some people endure long-term residual symptoms, such as fatigue and pain. Nursing input can be of value by providing support, information, explanations, and empathy to reassure patients and families. A greater understanding of the nature and course of the disease and its ramifications can lead to more effective nursing management and a faster rehabilitation process.

The placebo effect: dissolving the expectancy versus conditioning debate.

The authors review the literature on the 2 main models of the placebo effect: expectancy theory and classical conditioning. A path is suggested to dissolving the theoretical impasse that has long plagued this issue. The key is to make a clear distinction between 2 questions: What factors shape placebo effects? and What learning mediates the placebo effect? The reviewed literature suggests that classical conditioning procedures are one shaping factor but that verbal information can also shape placebo effects. The literature also suggests that conditioning procedures and other sources of information sometimes shape conscious expectancies and that these expectancies mediate some placebo effects; however, in other cases conditioning procedures appear to shape placebo effects that are not mediated by conscious cognition.

Driving-related fear: a review.

This article reviews the research on driving-related fear (DRF). Until recently, research has concentrated almost exclusively on the effect of motor vehicle accidents (MVAs) on subsequent levels of DRF. However, recent findings have suggested that MVAs are not solely responsible for this fear reaction, and that non-MVA driving fear can be just as strong. Studies of the broader driving-fearful population have encountered difficulty with diagnostic conceptualisation of DRF, although some have investigated a possible typology of DRF. Driving skill has been a neglected issue in the DRF research, and may prove to be a useful part of assessment and remediation of this potentially debilitating problem. Issues of definitional inconsistency are highlighted, and suggestions are made for several directions that future research might profitably take.

Type 2 tasks in the theory of signal detectability: discrimination between correct and incorrect decisions.

It has been known for over 40 years that there are two fundamentally different kinds of detection tasks in the theory of signal detectability. The Type 1 task is to distinguish between events defined independently of the observer; the Type 2 task is to distinguish between one's own correct and incorrect decisions about those Type 1 events. For the Type 1 task, the behavior of the detector can be summarized by the traditional receiver operating characteristic (ROC) curve. This curve can be compared with a theoretical ROC curve, which can be generated from overlapping probability functions conditional on the Type 1 events on an appropriate decision axis. We show how to derive the probability functions underlying Type 2 decisions from those for the Type 1 task. ROC curves and the usual measures of performance are readily obtained from those Type 2 functions, and some relationships among various Type 1 and Type 2 performance measures are presented. We discuss the relationship between Type 1 and Type 2 confidence ratings and caution against the practice of presenting transformed Type 2 ratings as empirical Type 1 ratings.

DHA supplementation improved both memory and reaction time in healthy young adults: a randomized controlled trial.

BACKGROUND: Docosahexaenoic acid (DHA) is important for brain function, and its status is dependent on dietary intakes. Therefore, individuals who consume diets low in omega-3 (n-3) polyunsaturated fatty acids may cognitively benefit from DHA supplementation. Sex and apolipoprotein E genotype (APOE) affect cognition and may modulate the response to DHA supplementation. OBJECTIVES: We investigated whether a DHA supplement improves cognitive performance in healthy young adults and whether sex and APOE modulate the response. DESIGN: Healthy adults (n = 176; age range: 18-45 y; nonsmoking and with a low intake of DHA) completed a 6-mo randomized, placebo-controlled, double-blind intervention in which they consumed 1.16 g DHA/d or a placebo. Cognitive performance was assessed by using a computerized cognitive test battery. For all tests, z scores were calculated and clustered into cognitive domains as follows: episodic and working memory, attention, reaction time (RT) of episodic and working memory, and attention and processing speed. ANCOVA was conducted with sex and APOE as independent variables. RESULTS: RTs of episodic and working memory improved with DHA compared with placebo [mean difference (95% CI): -0.18 SD (-0.33, -0.03 SD) (P = 0.02) and -0.36 SD (-0.58, -0.14 SD) (P = 0.002), respectively]. Sex × treatment interactions occurred for episodic memory (P = 0.006) and the RT of working memory (P = 0.03). Compared with the placebo, DHA improved episodic memory in women [0.28 SD (0.08, 0.48 SD); P = 0.006] and RTs of working memory in men [-0.60 SD (-0.95, -0.25 SD); P = 0.001]. APOE did not affect cognitive function, but there were some indications of APOE × sex × treatment interactions. CONCLUSIONS: DHA supplementation improved memory and the RT of memory in healthy, young adults whose habitual diets were low in DHA. The response was modulated by sex. This trial was registered at the New Zealand Clinical Trials Registry (http://www.anzctr.org.au/default.aspx) as ACTRN12610000212055.

Memory deficits in Parkinson's disease.

The purpose of this study was to investigate deficits in recognition, recall, and prospective memory among Parkinson's disease (PD) patients, and to ascertain whether task difficulty and disease severity moderate these deficits. Comparisons were made between 41 nondemented PD participants, divided into early-stage and advanced-stage groups, and 41 matched controls. PD participants exhibited deficits in recognition, recall, and prospective memory. The advanced-stage PD group produced greater deficits than the early-stage PD group in all tasks, suggesting that these deficits increase in step with overall disease severity. The results of the task difficulty manipulation provide a partial explanation for the inconsistencies in the literature concerning the existence of recognition memory deficits in PD.

Face recognition and aging: effects of target age and memory load.

In the present study, we investigated age-related decline in face recognition memory and whether this decline is moderated by the age of the target faces and by the number of faces that the participant must learn (memory load). Thirty-two participants in each of three age groups (18-39 years, 60-75 years, and 76-96 years) completed a face recognition task. Signal detection analyses confirmed that face recognition accuracy declined with age. However, this finding was qualified by an interaction between participant age and target age, which revealed that the age-related decline in face recognition accuracy occurred only for young target faces. Increased memory load was associated with comparable performance decrements across all age groups. However, memory load appears not to be the cause of these decrements. Instead, they appear to be a product of recognition load (the number of stimuli presented in the recognition phase).

Brief exposure to a 50 Hz, 100 microT magnetic field: effects on reaction time, accuracy, and recognition memory.

The present study investigated both the direct and delayed effects of a 50 Hz, 100 microT magnetic field on human performance. Eighty subjects completed a visual duration discrimination task, half being exposed to the field and the other half sham exposed. The delayed effects of this field were also examined in a recognition memory task that followed immediately upon completion of the discrimination task, Unlike our earlier studies, we were unable to find any effects of the field on reaction time and accuracy in the visual discrimination task. However, the field had a delayed effect on memory, producing a decrement in recognition accuracy. We conclude that after many years of experimentation, finding a set of magnetic field parameters and human performance measures that reliably yield magnetic field effects is proving elusive. Yet the large number of significant findings suggests that further research is warranted.

Neuropsychological assessment of individuals with expressive disabilities in addition to traumatic brain injuries.

Little empirical research has examined guidelines for neuropsychological assessment of people with severe physical and sensory disabilities. This study focused on people with expressive disabilities--people unable to speak, write, draw, or manipulate test materials. Measures were selected and adapted to be suitable for the assessment of cognitive functioning for such people. Responses were selected from multiple choice answers or were spelled out on an alphabet board. Individuals with expressive disabilities in addition to traumatic brain injuiry (TBI) were compared to individuals with TBI alone and a normative group. The measures were generally found to be reliable and valid assessment instruments. Individuals with expressive disabilities were able to manage the task requirements of the adapted tests. The results provided support for the adaptations trialed.