Search results for "Memory Disorders"
showing 10 items of 82 documents
Implicit memory functioning in schizophrenia: Explaining inconsistent findings of word stem completion tasks
2014
The definitive implicit memory profile of schizophrenia is yet to be clarified. Methodological differences between studies could be the reason for the inconsistent findings reported. In this study, we have examined implicit memory functioning using a word stem completion task. In addition, we have addressed methodological issues related with lexical and perceptual stimuli characteristics, and with the strategy used to calculate priming scores. Our data show similar performance values in schizophrenic patients and healthy controls. Furthermore, we have not detected significant differences in priming between the two groups, even when this parameter was calculated using three different procedu…
Perceptual priming in schizophrenia evaluated by word fragment and word stem completion
2011
Implicit memory seems to be preserved in schizophrenia as a whole, but dissociations between conceptual and perceptual tasks and between accuracy and reaction time measures have appeared. The present research has revealed some methodological limitations in many studies to date that are focused on the study of perceptual implicit memory in schizophrenic patients using accuracy measures. The review of these studies revealed that limitations are related to an inadequate definition of performance and priming measures, a lack of control over the characteristics of the stimuli, and the absence of information on the experimental procedures used in data collection. Moreover, the task used in these …
Taking both sides: do unilateral anterior temporal lobe lesions disrupt semantic memory?
2010
The most selective disorder of central conceptual knowledge arises in semantic dementia, a degenerative condition associated with bilateral atrophy of the inferior and polar regions of the temporal lobes. Likewise, semantic impairment in both herpes simplex virus encephalitis and Alzheimer's disease is typically associated with bilateral, anterior temporal pathology. These findings suggest that conceptual representations are supported via an interconnected, bilateral, anterior temporal network and that it may take damage to both sides to produce an unequivocal deficit of central semantic memory. We tested and supported this hypothesis by investigating a case series of 20 patients with unila…
Cortisol and trait anxiety as relevant factors involved in memory performance in people with drug-resistant epilepsy
2018
People with drug-resistant epilepsy are exposed to unpredictable and uncontrollable seizures, which can be considered as a chronic stress condition. Additionally, these patients present memory deficits and a high prevalence of depression and anxiety. Cortisol, the main stress hormone, has a modulatory role on memory in healthy individuals and patients with emotional disorders, but its role in memory and emotional processes remains unclear in people with epilepsy. This study analyzes the differences in cortisol levels in people with epilepsy with high and low memory performance, and the relationships among cortisol levels, epilepsy-related factors, memory, anxiety, and depression. Fifty-two …
Age at surgery as a predictor of cognitive improvements in patients with drug-resistant temporal epilepsy
2017
Temporal lobe epilepsy (TLE) surgery is an effective procedure that can produce cognitive changes. However, the prognostic factors related with cognitive outcomes need to be better understood. The aim of the present study is to know if age at surgery is a reliable predictor of verbal memory competence and considering factors such as: hemisphere; type of surgery; pre-surgical seizure frequency; and epilepsy duration. Sixty-one typically dominant patients with drug-resistant TLE (34 with left TLE [L-TLE] and 27 with right TLE [R-TLE]) underwent a neuropsychological assessment before and a year after surgery. Results showed that R-TLE patients had better evolution in short- and long-term verba…
The effect of associative strength on semantic priming in schizophrenia
2017
The present research was designed to investigate the pattern of semantic priming in schizophrenia as a function of strength of association (or semantic distance between concepts in the semantic network). Thirty schizophrenia patients, without formal thought disorder, and twenty-nine healthy controls participated in a lexical decision task in which prime-target associative strength (strong, weak and not related) and stimulus-onset asynchrony (SOA: 250 ms and 750 ms) were manipulated. Patients and controls showed the same associative strength effect on RTs. In the short SOA condition priming effects were obtained for both strong and weak prime-target associative conditions. However in the lon…
A Comparison of implicit memory tests in schizophrenic patients and normal controls
2007
The objective of the current study was to compare the performance of schizophrenic patients and normal controls on implicit memory tests. Two neuropsychological tasks were administered to 29 patients and normal participant samples. The implicit tests were: Word fragment completion and Word production from semantic categories. The priming score was the variable of interest. Priming effects are obtained in normal subjects and schizophrenia patients, regardless of the implicit test used. However, a dissociation in priming between normal and patient groups was observed, depending on the test used. For word fragment test, priming was identical between... (Ver más) the two groups. However, for wo…
Effects of Obsessive-Compulsive Symptoms on Neuropsychological Test Performance: Complicating an Already Complicated Story
2011
Theoretical models of obsessive-compulsive disorder (OCD) implicate neurocognitive dysfunction, particularly deficits in nonverbal memory and executive functioning, in the pathogenesis of the disorder. The opposite hypothesis (poor performance in neuropsychological test as an epiphenomenon of OCD symptoms) has rarely been contemplated although checking behavior, obsessional doubt, lack of motivation, and slowness as well as preoccupation with touching objects may result in secondary test impairment and mimic manifestations of neural dysfunction. A total of 60 patients with OCD and 30 healthy controls were tested with a multi-functional neuropsychological battery. At the end of the testing p…
Distinct neuropsychological profiles correspond to distribution of cortical thinning in inherited prion disease caused by insertional mutation
2012
Background The human prion diseases are a group of universally fatal neurodegenerative disorders associated with the auto-catalytic misfolding of the normal cell surface prion protein (PrP). Mutations causative of inherited human prion disease (IPD) include an insertion of six additional octapeptide repeats (6-OPRI) and a missense mutation (P102L) with large families segregating for each mutation residing in southern England. Here we report for the first time the neuropsychological and clinical assessments in these two groups. Method The cognitive profiles addressing all major domains were obtained for 26 patients (18 6-OPRI, 8 P102L) and the cortical thickness determined using 1.5T MRI in …
Visuospatial deficits in schizophrenia: central executive and memory subsystems impairments
2002
Object and spatial visual working memory are impaired in schizophrenic patients. It is not clear if the impairments reside in each memory subsystem alone or also in the central executive component that coordinates these processes. In order to elucidate which memory component is impaired, we developed a paradigm with single spatial and object working memory tasks and dual ones with two different delays (5 and 30 s). Fifteen schizophrenic patients and 14 control subjects performed these tests. Schizophrenic patients had a poorer performance compared to normal controls in all tasks and in all time delays. Both schizophrenics and controls performed significantly worse in the object task than in…