RESUMEN
The hippocampus is believed to be important for rapid learning of arbitrary stimulus-response contingencies, or S-R bindings. In support of this, Schnyer et al. (2006) (Experiment 2) measured priming of reaction times (RTs) to categorise visual objects, and found that patients with medial temporal lobe damage, unlike healthy controls, failed to show evidence of reduced priming when response contingencies were reversed between initial and repeated categorisation of objects (a signature of S-R bindings). We ran a similar though extended object classification task on 6 patients who appear to have selective hippocampal lesions, together with 24 age-matched controls. Unlike Schnyer et al. (2006), we found that reversing response contingencies abolished priming in both controls and patients. Bayes Factors provided no reason to believe that response reversal had less effect on patients than controls. We therefore conclude that it is unlikely that the hippocampus is needed for S-R bindings.
Asunto(s)
Aprendizaje por Asociación , Hipocampo/fisiopatología , Reconocimiento Visual de Modelos , Memoria Implícita , Adulto , Anciano , Análisis de Varianza , Aprendizaje por Asociación/fisiología , Femenino , Humanos , Juicio/fisiología , Masculino , Persona de Mediana Edad , Pruebas Neuropsicológicas , Reconocimiento Visual de Modelos/fisiología , Tiempo de Reacción , Memoria Implícita/fisiologíaRESUMEN
Focal lesions can affect connectivity between distal brain regions (connectional diaschisis) and impact the graph-theoretic properties of major brain networks (connectomic diaschisis). Given its unique anatomy and diverse range of functions, the hippocampus has been claimed to be a critical "hub" in brain networks. We investigated the effects of hippocampal lesions on structural and functional connectivity in six patients with amnesia, using a range of magnetic resonance imaging (MRI) analyses. Neuropsychological assessment revealed marked episodic memory impairment and generally intact performance across other cognitive domains. The hippocampus was the only brain structure exhibiting reduced grey-matter volume that was consistent across patients, and the fornix was the only major white-matter tract to show altered structural connectivity according to both diffusion metrics. Nonetheless, functional MRI revealed both increases and decreases in functional connectivity. Analysis at the level of regions within the default-mode network revealed reduced functional connectivity, including between nonhippocampal regions (connectional diaschisis). Analysis at the level of functional networks revealed reduced connectivity between thalamic and precuneus networks, but increased connectivity between the default-mode network and frontal executive network. The overall functional connectome showed evidence of increased functional segregation in patients (connectomic diaschisis). Together, these results point to dynamic reorganization following hippocampal lesions, with both decreased and increased functional connectivity involving limbic-diencephalic structures and larger-scale networks. © 2016 The Authors Hippocampus Published by Wiley Periodicals, Inc.
Asunto(s)
Amnesia/etiología , Lesiones Encefálicas/diagnóstico por imagen , Hipocampo/diagnóstico por imagen , Hipocampo/fisiopatología , Imagen por Resonancia Magnética , Adulto , Anciano , Amnesia/diagnóstico por imagen , Lesiones Encefálicas/complicaciones , Mapeo Encefálico , Femenino , Sustancia Gris/diagnóstico por imagen , Hipocampo/lesiones , Humanos , Procesamiento de Imagen Asistido por Computador , Masculino , Persona de Mediana Edad , Vías Nerviosas/diagnóstico por imagen , Pruebas Neuropsicológicas , Oxígeno/sangre , Sustancia Blanca/diagnóstico por imagenRESUMEN
Despite the marked impairment of recent episodic memories in Alzheimer's disease, there have been few attempts to rehabilitate these deficits. We used a novel external memory aid to promote recall of episodic memories in patients with mild to moderate Alzheimer's disease. SenseCam, a small wearable camera, recorded significant events in the lives of six Alzheimer's disease patients. Every two days for two weeks each patient's memory for an event was assessed, followed by a structured review of the SenseCam images. Longer-term recall was tested one and three months later. A written diary control condition followed the same procedure. Across 40 events the SenseCam review method resulted in significantly more details of an event being recalled over two weeks than the written diary method in five out of the six patients. At three months post event, four out of five patients (one had dropped out) recalled significantly more details of events in the SenseCam condition while the other patient showed no significant difference. Viewing SenseCam images of personally experienced events may significantly improve autobiographical memory in patients with even moderate Alzheimer's disease.
Asunto(s)
Enfermedad de Alzheimer/rehabilitación , Memoria Episódica , Dispositivos de Autoayuda , Anciano , Anciano de 80 o más Años , Enfermedad de Alzheimer/psicología , Femenino , Humanos , Masculino , Recuerdo Mental , Persona de Mediana Edad , Pruebas NeuropsicológicasRESUMEN
A wearable camera that takes pictures automatically, SenseCam, was used to generate images for rehearsal, promoting consolidation and retrieval of memories for significant events in a patient with memory retrieval deficits. SenseCam images of recent events were systematically reviewed over a 2-week period. Memory for these events was assessed throughout and longer-term recall was tested up to 6 months later. A written diary control condition followed the same procedure. The SenseCam review procedure resulted in significantly more details of an event being recalled, with twice as many details recalled at 6 months follow up compared to the written diary method. Self-report measures suggested autobiographical recollection was triggered by the SenseCam condition but not by reviewing the written diary. Emotional and social wellbeing questionnaires indicated improved confidence and decreased anxiety as a result of memory rehearsal using SenseCam images. We propose that SenseCam images provide a powerful boost to autobiographical recall, with secondary benefits for quality of life.
Asunto(s)
Disfunción Cognitiva/rehabilitación , Señales (Psicología) , Procesamiento de Imagen Asistido por Computador , Trastornos de la Memoria/terapia , Memoria Episódica , Recuerdo Mental , Microcomputadores , Fotograbar/instrumentación , Calidad de Vida , Dispositivos de Autoayuda , Inhibidores de la Colinesterasa/uso terapéutico , Disfunción Cognitiva/tratamiento farmacológico , Disfunción Cognitiva/psicología , Donepezilo , Monitoreo del Ambiente/instrumentación , Femenino , Humanos , Indanos/uso terapéutico , Registros Médicos , Trastornos de la Memoria/psicología , Persona de Mediana Edad , Nootrópicos/uso terapéutico , Piperidinas/uso terapéutico , AutoinformeRESUMEN
One of the most troubling symptoms of Alzheimer's disease is the loss of the patient's sense of identity. This loss complicates relationships, increases apathy, and generally impedes quality of life for the patient. We describe a novel in-home ambient display called Biography Theatre that cycles through music, photographs, movies, and narratives drawn from the patient's past and current life. We conducted an exploratory case study with an 84-year-old male with moderate-stage Alzheimer's disease (Mr H). The study consisted of three phases: a baseline phase, a phase wherein autobiographical materials were collected and discussed, and a phase wherein the display was deployed in the home. The patient demonstrated improvement on standardised tests of apathy and positive self-identity, but did not improve on tests of autobiographical memory, anxiety, depression, and general cognition. We also report on caregiver reactions to the intervention and how the display helped them cope with and reinterpret their loved one's condition. This work suggests that interdisciplinary work involving "off the desktop" computing technologies may be a fruitful way to provide rehabilitative benefit for individuals with Alzheimer's disease.