Context Memory in Korsakoff’s Syndrome

Memory for contextual information and target-context integration are crucial for successful episodic memory formation and are impaired in patients with Korsakoff’s syndrome. In this paper we review the evidence for the notion that a context memory deficit makes an important contribution to the amnesia in these patients. First, we focus on anterograde memory for contextual (spatial and temporal) information. Next, the use of contextual cues in memory retrieval is examined and their role in retrograde amnesia and confabulation. Evidence on the role of contextual cues and associations in working memory is discussed in relation to the underlying neurocognitive mechanisms and their dissociation from long-term encoding. Finally, we focus on implicit learning of contextual information in Korsakoff patients. It can be concluded that Korsakoff patients are impaired in the explicit processing of contextual information and in target-context binding, both in long-term (retrograde and anterograde) memory and in working memory. These results extend the context memory deficit hypothesis. In contrast, implicit contextual learning is relatively preserved in these patients. These findings are discussed in relation to evidence of dysfunction of the extended diencephalic-hippocampal memory circuit in Korsakoff’s syndrome

Psychogenic amnesia: syndromes, outcome, and patterns of retrograde amnesia

There are very few case series of patients with acute psychogenic memory loss (also known as dissociative/functional amnesia), and still fewer studies of outcome, or comparisons with neurological memory-disordered patients. Consequently, the literature on psychogenic amnesia is somewhat fragmented and offers little of prognostic value for individual patients. In the present study, we reviewed the case records and neuropsychological findings in 53 psychogenic amnesia cases (3M:1F), in comparison with 21 consecutively recruited neurological memory-disordered patients and 14 healthy controls. In particular, we examined the pattern of retrograde amnesia on an assessment of autobiographical memory (the Autobiographical Memory Interview). We found that our patients with psychogenic memory loss fell into four distinct groups, which we categorised as: (i) fugue state, (ii) fugue-to-focal retrograde amnesia, (iii) psychogenic focal retrograde amnesia following a minor neurological episode, and (iv) patients with gaps in their memories. While neurological cases were characterised by relevant neurological symptoms, a history of a past head injury was actually more common in our psychogenic cases (p=0.012), perhaps reflecting a ‘learning episode’ predisposing to later psychological amnesia. As anticipated, loss of the sense of personal identity was confined to the psychogenic group. However, clinical depression, family/relationship problems, financial/employment problems, and failure to recognise the family were also statistically more common in that group. The pattern of autobiographical memory loss differed between the psychogenic groups: fugue cases showed a severe and uniform loss of memories for both facts and events across all time-periods, whereas the two focal retrograde amnesia groups showed a ‘reversed’ temporal gradient with relative sparing of recent memories. After 3-6 months, the fugue patients had improved to normal scores for facts and near-normal scores for events. By contrast, the two focal retrograde amnesia groups showed a lesser improvement and continued to show a reversed temporal gradient. In conclusion, the outcome in psychogenic amnesia, particularly those characterised by fugue, is better than generally supposed. Findings are interpreted in terms of Markowitsch’s and Kopelman’s models of psychogenic amnesia, and with respect to Anderson’s neuroimaging findings in memory inhibition

Differences in trajectories of quality of life according to type of dementia: 6-year longitudinal findings from the IDEAL programme

Background: People with different types of dementia may have distinct symptoms and experiences that affect their quality of life. This study investigated whether quality of life varied across types of dementia and over time. Methods: The participants were 1555 people with mild-to-moderate dementia and 1327 carers from the IDEAL longitudinal cohort study, recruited from clinical services. As many as possible were followed for up to 6 years. Diagnoses included were Alzheimer’s disease, vascular dementia, mixed Alzheimer’s and vascular dementia, Parkinson’s disease dementia, dementia with Lewy bodies, and frontotemporal dementia. Self- and informant-rated versions of the Quality of Life in Alzheimer’s Disease scale were used. A joint model, incorporating a mixed effects model with random effects and a survival model to account for dropout, was used to examine whether quality of life varied by dementia type at the time of diagnosis and how trajectories changed over time. Results: The strongest associations between dementia type and quality of life were seen around the time of diagnosis. For both self-ratings and informant ratings, people with Parkinson’s disease dementia or dementia with Lewy bodies had lower quality of life scores. Over time there was little change in self-rated scores across all dementia types (− 0.15 points per year). Informant-rated scores declined over time (− 1.63 points per year), with the greatest decline seen in ratings by informants for people with dementia with Lewy bodies (− 2.18 points per year). Conclusions: Self-rated quality of life scores were relatively stable over time whilst informant ratings showed a steeper decline. People with Parkinson’s disease dementia or dementia with Lewy bodies report particularly low levels of quality of life, indicating the importance of greater attention to the needs of these groups

A Feasibility Study of Quantifying Longitudinal Brain Changes in Herpes Simplex Virus (HSV) Encephalitis Using Magnetic Resonance Imaging (MRI) and Stereology.

OBJECTIVES: To assess whether it is feasible to quantify acute change in temporal lobe volume and total oedema volumes in herpes simplex virus (HSV) encephalitis as a preliminary to a trial of corticosteroid therapy. METHODS: The study analysed serially acquired magnetic resonance images (MRI), of patients with acute HSV encephalitis who had neuroimaging repeated within four weeks of the first scan. We performed volumetric measurements of the left and right temporal lobes and of cerebral oedema visible on T2 weighted Fluid Attenuated Inversion Recovery (FLAIR) images using stereology in conjunction with point counting. RESULTS: Temporal lobe volumes increased on average by 1.6% (standard deviation (SD 11%) in five patients who had not received corticosteroid therapy and decreased in two patients who had received corticosteroids by 8.5%. FLAIR hyperintensity volumes increased by 9% in patients not receiving treatment with corticosteroids and decreased by 29% in the two patients that had received corticosteroids. CONCLUSIONS: This study has shown it is feasible to quantify acute change in temporal lobe and total oedema volumes in HSV encephalitis and suggests a potential resolution of swelling in response to corticosteroid therapy. These techniques could be used as part of a randomized control trial to investigate the efficacy of corticosteroids for treating HSV encephalitis in conjunction with assessing clinical outcomes and could be of potential value in helping to predict the clinical outcomes of patients with HSV encephalitis

The effect of body mass index on global brain volume in middle-aged adults: a cross sectional study

BACKGROUND: Obesity causes or exacerbates a host of medical conditions, including cardiovascular, pulmonary, and endocrine diseases. Recently obesity in elderly women was associated with greater risk of dementia, white matter ischemic changes, and greater brain atrophy. The purpose of this study was to determine whether body type affects global brain volume, a marker of atrophy, in middle-aged men and women. METHODS: T1-weighted 3D volumetric magnetic resonance imaging was used to assess global brain volume for 114 individuals 40 to 66 years of age (average = 54.2 years; standard deviation = 6.6 years; 43 men and 71 women). Total cerebrospinal fluid and brain volumes were obtained with an automated tissue segmentation algorithm. A regression model was used to determine the effect of age, body mass index (BMI), and other cardiovascular risk factors on brain volume and cognition. RESULTS: Age and BMI were each associated with decreased brain volume. BMI did not predict cognition in this sample; however elevated diastolic blood pressure was associated with poorer episodic learning performance. CONCLUSION: These findings suggest that middle-aged obese adults may already be experiencing differentially greater brain atrophy, and may potentially be at greater risk for future cognitive decline

Improving the experience of dementia and enhancing active life -living well with dementia: study protocol for the IDEAL study

Abstract Background: Enabling people with dementia and carers to 'live well' with the condition is a key United Kingdom policy objective. The aim of this project is to identify what helps people to live well or makes it difficult to live well in the context of having dementia or caring for a person with dementia, and to understand what 'living well' means from the perspective of people with dementia and carers

Autobiographical thinking interferes with episodic memory consolidation

New episodic memories are retained better if learning is followed by a few minutes of wakeful rest than by the encoding of novel external information. Novel encoding is said to interfere with the consolidation of recently acquired episodic memories. Here we report four experiments in which we examined whether autobiographical thinking, i.e. an 'internal' memory activity, also interferes with episodic memory consolidation. Participants were presented with three wordlists consisting of common nouns; one list was followed by wakeful rest, one by novel picture encoding and one by autobiographical retrieval/future imagination, cued by concrete sounds. Both novel encoding and autobiographical retrieval/future imagination lowered wordlist retention significantly. Follow-up experiments demonstrated that the interference by our cued autobiographical retrieval/future imagination delay condition could not be accounted for by the sound cues alone or by executive retrieval processes. Moreover, our results demonstrated evidence of a temporal gradient of interference across experiments. Thus, we propose that rich autobiographical retrieval/future imagination hampers the consolidation of recently acquired episodic memories and that such interference is particularly likely in the presence of external concrete cues

Micromechanical Properties of Injection-Molded Starch–Wood Particle Composites

The micromechanical properties of injection molded starch–wood particle composites were investigated as a function of particle content and humidity conditions. The composite materials were characterized by scanning electron microscopy and X-ray diffraction methods. The microhardness of the composites was shown to increase notably with the concentration of the wood particles. In addition,creep behavior under the indenter and temperature dependence were evaluated in terms of the independent contribution of the starch matrix and the wood microparticles to the hardness value. The influence of drying time on the density and weight uptake of the injection-molded composites was highlighted. The results revealed the role of the mechanism of water evaporation, showing that the dependence of water uptake and temperature was greater for the starch–wood composites than for the pure starch sample. Experiments performed during the drying process at 70°C indicated that the wood in the starch composites did not prevent water loss from the samples.Peer reviewe