Humans excel in familiar face recognition, but often find it hard to make identity judgements of unfamiliar faces. Understanding of the factors underlying the substantial benefits of familiarity is at present limited, but the effect is sometimes qualified by the way in which a face is known -for example, personal acquaintance sometimes gives rise to stronger familiarity effects than exposure through the media. Given the different quality of personal versus media knowledge, for example in one's emotional response or level of interaction, some have suggested qualitative differences between representations of people known personally or from media exposure. Alternatively, observed differences could reflect quantitative differences in the level of familiarity. We present four experiments investigating potential contributory influences to face familiarity effects in which observers view pictures showing their friends, favourite celebrities, celebrities they dislike, celebrities about whom they have expressed no opinion, and their own face. Using event-related potential indices with high temporal resolution and multiple highly varied everyday ambient images as a strong test of face recognition, we focus on the N250 and the later Sustained Familiarity Effect (SFE). All known faces show qualitatively similar responses relative to unfamiliar faces. Regardless of personal-or media-based familiarity, N250 reflects robust visual representations, successively refined over increasing exposure, whilst SFE appears to reflect the amount of identity-specific semantic information known about a person. These modulations of visual and semantic representations are consistent with face recognition models which emphasise the degree of familiarity but do not distinguish between different types of familiarity.

Introduction: Stroke survivors are routinely screened for cognitive impairment with tools that often fail to detect subtle impairments. The Oxford Cognitive Screen-Plus (OCS-Plus) is a brief tablet-based screen designed to detect subtle post-stroke cognitive impairments. We examined its psychometric properties in two UK English-speaking stroke cohorts (subacute: <3 months post-stroke, chronic: >6 months post-stroke) cross-sectionally. Patients and methods: This study included 347 stroke survivors (mean age = 73 years; mean education = 13 years; 43.06% female; 74.42% ischaemic stroke). The OCS-Plus was completed by 181 sub-acute stroke survivors and 166 chronic stroke survivors. All participants also completed the Oxford Cognitive Screen (OCS) and a subset completed the Montreal Cognitive Assessment (MoCA) and further neuropsychological tests. Results: First, convergent construct validity of OCS-Plus tasks to task-matched standardized neuropsychological tests was confirmed ( r > 0.30). Second, we evaluated divergent construct validity of all OCS-Plus subtasks ( r < 0.19). Third, we report the sensitivity and specificity of each OCS-Plus subtask compared to neuropsychological test performance. Fourth, we found that OCS-Plus detected cognitive impairments in a large proportion of those classed as unimpaired on MoCA (100%) and OCS (98.50%). Discussion and conclusion: The OCS-Plus provides a valid screening tool for sensitive detection of subtle cognitive impairment in stroke patients. Indeed, the OCS-Plus detected subtle cognitive impairment at a similar level to validated neuropsychological assessments and exceeded detection of cognitive impairment compared to standard clinical screening tools.

BACKGROUNDThere is a high prevalence of executive function impairments among stroke survivors. However, the underlying aetiology remains unclear. In particular, we address whether focal, stroke-specific white matter damage or diffuse comorbid white matter damage (leukoaraiosis) is more associated with executive function impairments.METHODSThis project is a retrospective analysis of data collected within the Oxford Cognitive Screening programme. Patients were recruited in the acute stage of stroke if they had a confirmed diagnosis of stroke, were at least 18 years of age, were able to remain alert for 20 minutes, and were able to provide informed consent. Patients in the present analysis completed follow up neuropsychological assessment at six-months with the Oxford Cognitive Screen-Plus to assess executive function. Stroke lesions were manually delineated on acute clinical brain scans allowing us to quantify focal stroke-specific white matter damage using the HCP-842 tractography atlas. Leukoaraiosis was visually rated on clinical scans using the Age-Related White Matter Changes scale.RESULTSThis study included data from 90 stroke patients (mean age = 73.76 years; 47.78% female). Multiple linear regression analyses showed that the presence of leukoaraiosis predicted poorer executive functioning six-months after stroke (B = −0.33, p = .031, 95% CI [-0.64 - 0.03]). However, post-stroke executive functioning was not predicted by stroke-specific damage to white matter tracts.CONCLUSIONSOverall, these results provide novel insight into the neural substrates underlying post-stroke executive dysfunction and highlight the prognostic utility of using routine clinical CT scans to assess leukoaraiosis.

ObjectivesClinical guidelines recommend early cognitive assessment after stroke to inform rehabilitation and discharge decisions. However, little is known about stroke survivors’ experiences of the cognitive assessment process. This qualitative study aimed to explore patients’ experiences of poststroke cognitive assessments.DesignStroke survivors were purposively sampled in an iterative process through a pool of research volunteers who had previously taken part in the Oxford Cognitive Screen Recovery study. Stroke survivors and their family caregivers were invited to participate in a semistructured interview steered by a topic guide. Interviews were audio recorded, transcribed and analysed using reflexive thematic analysis. Demographic, clinical and cognitive data were acquired from patients’ previous research data.SettingStroke survivors were originally recruited from the acute inpatient unit at Oxford University Hospital (John Radcliffe), UK. Participants were interviewed after discharge either at their homes or via telephone or videocall.ParticipantsTwenty-six stroke survivors and eleven caregivers participated in semi-structured interviews.ResultsWe identified three key phases of the cognitive assessment process and themes pertaining to each phase. The phases (numbered) and themes (lettered) were as follows: (1) before the cognitive assessment: (A) lack of explanation, (B) considering the assessment useless; (2) during the cognitive assessment: varied emotional responses, moderated by (D) perception of the purpose behind cognitive assessment, (E) perception of cognitive impairment, (F) confidence in cognitive abilities, (G) assessment administration style and (3) after the cognitive assessment: (H) feedback can impact self-confidence and self-efficacy, (I) vague feedback and clinical jargon are unhelpful.ConclusionsStroke survivors require clear explanations about the purpose and outcomes of poststroke cognitive assessments, including constructive feedback, to promote engagement with the process and protect their psychological wellbeing.

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