The 'curse of knowledge': when medical expertise can sometimes be a liability.

Medical expertise is associated with excellent patient care and good clinical decision making. While this generally remains true, there is an increasing body of evidence to suggest that in some cases medical expertise can be a liability, with errors more likely to occur in medical experts than in junior staff. Increased awareness of this 'curse of knowledge' may result in better patient safety.

Andrew Mayes' expert analysis of a case of memory distortion.

In this single-case study of memory distortion where Andrew Mayes was involved as an expert witness, a surgeon falsely recalled aspects of a patient safety adverse event in which he was involved, and where he was put through an investigatory process by a regulatory body. Andrew Mayes' expert analysis of the role of memory distortion in this case resulted in the surgeon being exonerated.

Systematic Review and Meta-Analysis of Brief Cognitive Instruments to Evaluate Suspected Dementia in Chinese-Speaking Populations.

Background: Chinese is the most commonly spoken world language; however, most cognitive tests were developed and validated in the West. It is essential to find out which tests are valid and practical in Chinese speaking people with suspected dementia. Objective: We therefore conducted a systematic review and meta-analysis of brief cognitive tests adapted for Chinese-speaking populations in people presenting for assessment of suspected dementia. Methods: We searched electronic databases for studies reporting brief (≤20 minutes) cognitive test's sensitivity and specificity as part of dementia diagnosis for Chinese-speaking populations in clinical settings. We assessed quality using Centre for Evidence Based Medicine (CEBM) criteria and translation and cultural adaptation using the Manchester Translation Reporting Questionnaire (MTRQ), and Manchester Cultural Adaptation Reporting Questionnaire (MCAR). We assessed heterogeneity and combined sensitivity in meta-analyses. Results: 38 studies met inclusion criteria and 22 were included in meta-analyses. None met the highest CEBM criteria. Five studies met the highest criteria of MTRQ and MCAR. In meta-analyses of studies with acceptable heterogeneity (I2 <  75%), Addenbrooke's Cognitive Examination Revised &III (ACE-R & ACE-III) had the best sensitivity and specificity; specifically, for dementia (93.5% & 85.6%) and mild cognitive impairment (81.4% & 76.7%). Conclusions: Current evidence is that the ACE-R and ACE-III are the best brief cognitive assessments for dementia and mild cognitive impairment in Chinese-speaking populations. They may improve time taken to diagnosis, allowing people to access interventions and future planning.

Evidence for superior encoding of detailed visual memories in deaf signers.

Recent evidence shows that deaf signers outperform hearing non-signers in some tests of visual attention and discrimination. Furthermore, they can retain visual information better over short periods, i.e., seconds. However, it is unknown if deaf signers' retention of detailed visual information is superior following more extended periods. We report a study investigating this possibility. Our data revealed that deaf individuals outperformed hearing people in a visual long-term memory test that probed the fine detail of new memories. Deaf individuals also performed better in a scene-discrimination test, which correlated positively with performance on the long-term memory test. Our findings provide evidence that deaf signers can demonstrate superior visual long-term memory, possibly because of enhanced visual attention during encoding. The relative contributions of factors including sign language fluency, protracted practice, and neural plasticity are still to be established. Our findings add to evidence showing that deaf signers are at an advantage in some respects, including the retention of detailed visual memories over the longer term.

Functional Cognitive Disorder: Differential Diagnosis of Common Clinical Presentations.

BACKGROUND: Cognitive symptoms in the absence of neurological disease are common. Functional cognitive disorder (FCD) has been conceptualized as a cognitive subtype of functional neurological disorder. Although FCD is understood as different from exaggerated or feigned cognitive complaints, previous accounts have provided little practical advice on how FCD can be separated from factitious or malingered cognitive complaints. Also, the distinction of FCD from other medical or mental health disorders that impact on cognition is an area of ongoing study and debate. Diagnostic precision is important to prevent iatrogenesis and for the development of needed treatment protocols. METHOD: We summarize the current literature and present seven anonymized case vignettes to characterize the challenges in this area and develop proposals for solutions. RESULTS/CONCLUSIONS: Recognizing the limitations of categorical diagnostic systems, we position FCD as distinct from feigning and cognitive symptoms of psychiatric disorders, although with overlapping features. We set out typical clinical features and neuropsychological profiles for each category of cognitive disorder and a statistical method to analyze performance validity tests/effort tests to assist in determining feigned or invalid responding.

Dementia Early-Stage Cognitive Aids New Trial (DESCANT) of memory aids and guidance for people with dementia: randomised controlled trial.

BACKGROUND: Common memory aids for people with dementia at home are recommended. However, rigorous evaluation is lacking, particularly what guidance or support is valued. OBJECTIVE: To investigate effects of memory aids and guidance by dementia support practitioners (DSPs) for people in early-stage dementia through a pragmatic, randomised controlled trial. METHODS: Of 469 people with mild-to-moderate dementia and their informal carers, 468 were randomised to a DSP with memory aids or to usual care plus existing dementia guide. Allocation was stratified by Trust/Health Board; time since first attendance at memory service; gender; age; and living with primary carer or not. Primary outcome was Bristol Activities of Daily Living Scale (BADLS) Score at 3 and 6 months (primary end-point). Secondary outcomes for people with dementia: quality of life (CASP-19; DEMQOL); cognition and functioning (Clinical Dementia Rating Scale; S-MMSE); capability (ICECAP-O); social networks (LSNS-R); and instrumental daily living activities (R-IDDD). Secondary outcomes for carers: psychological health (GHQ-12); sense of competence (SSCQ). RESULTS: DSPs were successfully trained, compliance was good and welcomed by participants. Mean 6 months BADLS Score increased to 14.6 (SD: 10.4) in intervention and 12.6 (SD: 8.1) in comparator, indicative of greater dependence in the activities of daily living. Adjusted between-group difference was 0.38 (95% CI: -0.89 to 1.65, p=0.56). Though this suggests greater dependency in the intervention group the difference was not significant. No differences were found in secondary outcomes. CONCLUSIONS: This intervention did not maintain independence in the activities of daily living with no improvement in other outcomes for people with dementia or carers. TRIAL REGISTRATION NUMBER: Current Controlled Trials ISRCTN12591717.

Validation of the Taiwanese Version of ACE-III (T-ACE-III) to Detect Dementia in a Memory Clinic.

OBJECTIVE: The Addenbrooke's Cognitive Examination III (ACE-III) is a 100-points cognitive test used in detecting dementia in many countries. There has been no validation study of the ACE-III in patients with suspected dementia in a Taiwanese population, where the language is traditional Chinese. We aimed to culturally adapt and validate the ACE-III as a cognitive assessment tool for differentiating between people with and without dementia presenting to healthcare professionals in Taiwan with possible dementia. METHODS: We culturally adapted the ACE-III for Taiwan (T-ACE-III) and tested it with consenting patients with suspected dementia in northern Taiwan who had been through the diagnostic process. We calculated receiver operating characteristic (ROC) curves to test the ability of the T-ACE-III to differentiate between dementia and non-dementia cases using clinician diagnosis as the gold standard. We generated the Youden Index to determine the best cut-off score. RESULTS: We recruited 90 Taiwanese individuals aged 49-93 years: 24 males and 33 females had dementia and 12 males and 21 females did not. The area under the ROC curve was 0.99 for distinguishing dementia from non-dementia. The T-ACE-III had a sensitivity of 100% and specificity of 78.8% when the cut-off score was 86/87. With a cut-off value of 73/74, the specificity was 100.0%, and sensitivity 89.5%. The highest Youden Index was 0.895, indicating the best overall cut-off point to be 73/74. CONCLUSIONS: The T-ACE-III is an acceptable cognitive test with excellent psychometric properties for discriminating dementia from non-dementia in Taiwanese populations in memory clinic settings.

The syndrome of transient epileptic amnesia: a combined series of 115 cases and literature review.

The term transient epileptic amnesia was coined in 1990 to describe a form of epilepsy causing predominantly amnestic seizures which could be confused with episodes of Transient Global Amnesia. Subsequent descriptions have highlighted its association with 'atypical' forms of memory disturbance including accelerated long-term forgetting, disproportionate autobiographical amnesia and topographical amnesia. However, this highly treatment-responsive condition remains under-recognized and undertreated. We describe the clinical and neuropsychological features in 65 consecutive cases of transient epileptic amnesia referred to our study, comparing these to our previous cohort of 50 patients and to those reported in 102 literature cases described since our 2008 review. Findings in our two cohorts are substantially consistent: The onset of transient epileptic amnesia occurs at an average age of 62 years, giving rise to amnestic episodes at a frequency of around 1/month, typically lasting 15-30 min and often occurring on waking. Amnesia is the only manifestation of epilepsy in 24% of patients; olfactory hallucinations occur in 43%, motor automatisms in 41%, brief unresponsiveness in 39%. The majority of patients describe at least one of the atypical forms of memory disturbance mentioned above; easily provoked tearfulness is a common accompanying feature. There is a male predominance (85:30). Epileptiform changes were present in 35% of cases, while suspected causative magnetic resonance imaging abnormalities were detected in only 5%. Seizures ceased with anticonvulsant treatment in 93% of cases. Some clinical features were detected more commonly in the second series than the first, probably as a result of heightened awareness. Neuropsychological testing and comparison to two age and IQ-matched control groups (n = 24 and 22) revealed consistent findings across the two cohorts, namely elevated mean IQ, preserved executive function, mild impairment at the group level on standard measures of memory, with additional evidence for accelerated long-term forgetting and autobiographical amnesia, particularly affecting episodic recollection. Review of the literature cases revealed broadly consistent features except that topographical amnesia, olfactory hallucinations and emotionality have been reported rarely to date by other researchers. We conclude that transient epileptic amnesia is a distinctive syndrome of late-onset limbic epilepsy of unknown cause, typically occurring in late middle age. It is an important, treatable cause of memory loss in older people, often mistaken for dementia, cerebrovascular disease and functional amnesia. Its aetiology, the monthly occurrence of seizures in some patients and the mechanisms and interrelationships of the interictal features-amnestic and affective-all warrant further study.

Distinct performance profiles on the Brixton test in frontotemporal dementia.

The Brixton Spatial Anticipation Test is a well-established test of executive function that evaluates the capacity to abstract, follow, and switch rules. There has been remarkably little systematic analysis of Brixton test performance in the prototypical neurodegenerative disorder of the frontal lobes: behavioural variant frontotemporal dementia (bvFTD) or evaluation of the test's ability to distinguish frontal from temporal lobe degenerative disease. We carried out a quantitative and qualitative analysis of Brixton performance in 76 patients with bvFTD and 34 with semantic dementia (SD) associated with temporal lobe degeneration. The groups were matched for demographic variables and illness duration. The bvFTD group performed significantly more poorly (U = 348, p < .0001, r = .58), 53% of patients scoring in the poor-impaired range compared with 6% of SD patients. Whereas bvFTD patients showed problems in rule acquisition and switching, SD patients did not, despite their impaired conceptual knowledge. Error analysis revealed more frequent perseverative errors in bvFTD, particularly responses unconnected to the stimulus, as well as random responses. Stimulus-bound errors were rare. Within the bvFTD group, there was variation in performance profile, which could not be explained by demographic, neurological, or genetic factors. The findings demonstrate sensitivity and specificity of the Brixton test in identifying frontal lobe degenerative disease and highlight the clinical value of qualitative analysis of test performance. From a theoretical perspective, the findings provide evidence that semantic knowledge and the capacity to acquire rules are dissociable. Moreover, they exemplify the separable functional contributions to executive performance.

Does learning the Qur'an improve memory capacity? Practical and theoretical implications.

Our understanding of human memory has gained greatly from the study of individuals with impaired memory but rather less from outstandingly high levels of memory performance. Exceptions include the case of London taxi drivers whose extensive route learning results in modification of their hippocampus. Our study involves a group whose extensive verbal learning potentially provides a similar natural experiment. The Muslim faith encourages followers to memorise the whole of the Qur'an, some 77,449 words in its classic Arabic form. Successful memorisers are known as "Hafiz". We tested 10 Hafiz, 12 background-matched Muslim controls and 10 non-Muslim participants, on their detailed knowledge of the Qur'an and on their performance on standard measures of verbal and visuospatial learning. We found no differences between the three groups in their capacity to memorise verbal or visuospatial material and hence no evidence of generalisation of learning capacity in the Hafiz group. More surprisingly, however, half of the Hafiz group did not understand Arabic but were equivalent in Qur'anic memory to those who did. Given the importance that meaning is typically assumed to play in long-term memory, this was unexpected. We discuss the practical and theoretical implications of these results for verbal memory and long-term learning.

Clinical negligence: Understanding why things go wrong.

Clinical negligence claims are on the rise, with lawyers often playing a leading part in ascertaining what went wrong, why it went wrong and what lessons can be learned. I present a schema which may help lawyers better understand what goes wrong in clinical negligence cases.

Paradoxes in rehabilitation.

Paradoxical enhancement and paradoxical recovery of function after brain injury harmonize well with the concept of "ultrabilitation" and its focus on novel forms of flourishing in rehabilitation settings. I consider three sets of paradoxes which may impact on brain injury rehabilitation. Firstly, I consider post-traumatic growth after brain injury and its key determinants. Secondly, I review the role of illusions in rehabilitation and the paradox that some clinical conditions may be improved by invoking perceptual distortions. Thirdly, I consider paradoxical recovery profiles after brain injury, since knowledge of such paradoxical profiles may help inform attempts at rehabilitation of some patients. Finally, I consider how some of these paradoxes relate to components of ultrabilitation, and in addition to the nascent field of positive neuropsychology and the concept of resilience after brain injury.Implications for rehabilitationIllusions can sometimes be harnessed as a therapeutic tool in rehabilitation.There may be spontaneous, positive outcomes of an injury or illness, in the form of "post-traumatic growth", and these should be considered as part of a holistic therapeutic approach in rehabilitation.Some patients make an exceptional recovery from a severe brain insult, and lessons could be learned from such cases, such as disciplined use of compensatory strategies, which could have broader implications for neurorehabilitation.