Rocío Sánchez-Carrión

A longitudinal fMRI study of working memory in severe TBI patients with diffuse axonal injury.

Traumatic brain injury (TBI) patients have working memory deficits and altered patterns of brain activation during this function. The evolution of the impairment has not been examined to date. This study investigated longitudinal changes in brain activation during a working memory task. Twelve patients with severe and diffuse TBI and ten healthy matched controls were fMRI scanned twice at a 6-month interval during an n-back task (0-, 2- and 3-back). All the TBI patients selected presented signs of diffuse axonal injury on CT but had no evidence of focal lesions on MRI clinical examination. Significant changes in brain activation over time were observed in patients, but not in controls. During the first examination, though both groups engaged bilateral fronto-parietal regions known to be involved in working memory, activation of the right superior frontal gyrus was low in the TBI group. However, the difference between TBI and controls had decreased significantly after 6 months. A factor analysis confirmed the greater increase in activation in the right superior frontal cortex in the TBI group than in healthy controls, leading to normalization of the brain activation pattern. In conclusion, this longitudinal study provides evidence of a progressive normalization of the working memory activation pattern after diffuse axonal injury in severe TBI, coinciding with an improvement in performance on this function.

Frontal Hypoactivation on Functional Magnetic Resonance Imaging in Working Memory after Severe Diffuse Traumatic Brain Injury

Working memory is frequently impaired after traumatic brain injury (TBI). The present study aimed to investigate working memory deficits in patients with diffuse axonal injury and to determine the contribution of cerebral activation dysfunctions to them. Eighteen patients with severe TBI and 14 healthy controls matched for age and gender were included in the study. TBI patients were selected according to signs of diffuse axonal injury on computed tomography (CT) and without any evidence of focal lesions on MRI clinical examination. Functional magnetic resonance (fMRI) was used to assess brain activation during n-back tasks (0-, 2-, and 3-back). Compared to controls, the TBI group showed significant working memory impairment on the Digits Backwards (p=0.022) and Letter-Number Sequencing subtests from the WAIS-III (p<0.001) under the 2-back (p=0.008) and 3-back (p=0.017) conditions. Both groups engaged bilateral fronto-parietal regions known to be involved in working memory, although patients showed less cerebral activation than did controls. Decreased activation in TBI patients compared to controls was observed mainly in the right superior and middle frontal cortex. The correlation patterns differed between patients and controls: while the control group showed a negative correlation between performance and activation in prefrontal cortex (PFC), TBI patients presented a positive correlation in right parietal and left parahippocampus for the low and high working memory load, respectively. In conclusion, severe TBI patients with diffuse brain damage show a pattern of cerebral hypoactivation in the right middle and superior frontal regions during working memory tasks, and also present an impaired pattern of performance correlations.

Diffusion tensor imaging differences relate to memory deficits in diffuse traumatic brain injury

BackgroundMemory is one of the most impaired functions after traumatic brain injury (TBI). We used diffusion tensor imaging (DTI) to determine the structural basis of memory deficit. We correlated fractional anisotropy (FA) of the fasciculi connecting the main cerebral regions that are involved in declarative and working memory functions.MethodsFifteen patients with severe and diffuse TBI and sixteen healthy controls matched by age and years of education were scanned. The neuropsychological assessment included: Letter-number sequencing test (LNS), 2-back task, digit span (forwards and backwards) and the Rivermead profilet. DTI was analyzed by a tract-based spatial statics (TBSS) approach.ResultsWhole brain DTI analysis showed a global decrease in FA values that correlated with the 2-back d-prime index, but not with the Rivermead profile. ROI analysis revealed positive correlations between working memory performance assessed by 2-back d-prime and superior longitudinal fasciculi, corpus callosum, arcuate fasciculi and fornix. Declarative memory assessed by the Rivermead profile scores correlated with the fornix and the corpus callosum.ConclusionsDiffuse TBI is associated with a general decrease of white matter integrity. Nevertheless deficits in specific memory domains are related to different patterns of white matter damage.

Neuropsychological profile of persons with anoxic brain injury: Differences regarding physiopathological mechanism

Primary objective: To determine the neuropsychological profile of persons with anoxic brain injury. Methods and procedures: A retrospective study on a population of persons with anoxic brain injury admitted to a Brain Injury Unit (Institut Guttmann, Spain) from 1995–2003. The sample was divided according to physiopathological mechanisms in two sub-groups: ischemic anoxia (21 cases) and hypoxemic anoxia (11 cases). Functions assessed included orientation, attention, language, visuo-perceptive and visuo-constructive processing and verbal memory. Results: Neuropsychological assessment showed diffuse cognitive impairment in all assessed functions. Episodes of ischemic anoxia caused more severe verbal memory and learning problems than episodes of hypoxemic anoxia. Conclusions: This study shows that memory problems are the most prominent and relevant impairment, although all other cognitive functions are also impaired, affecting both memory itself and general behaviour. Statistical analysis also provides preliminary evidence on the different profile of memory impairment whether cerebral anoxia had hypoxic or ischemic origin.

Variabilidad interindividual en la recuperación después de un traumatismo craneoencefálico: efecto de la reserva cognitiva

BACKGROUND AND OBJECTIVE The aim of this study was to examine the effect of cognitive reserve in recovery after a moderate or severe traumatic brain injury (TBI). Different authors proposed that this construct might account for the mismatch between TBI severity, its clinical expression, and subsequent recovery. PATIENTS AND METHOD Eighty-four patients who sustained moderate-to-severe TBI participated in the study. Participants were divided into a high cognitive reserve group (n=46) or low cognitive reserve group (n=38) based on premorbid educational and occupational attainment. Patients functional status was examined with the Patient Competency Rating Scale (PCRS). RESULTS There were no significant differences between groups in demographic and injury variables (sex, age, severity of injury, post-traumatic amnesia duration, and time since injury). The analysis revealed statistically significant differences between the 2 groups on the PCRS: The high cognitive reserve group scored better than the low cognitive reserve group. CONCLUSIONS The results of this study suggest that cognitive reserve may mediate recovery after a moderate or severe TBI. Educational and occupational attainments provide a cognitive provision that would be associated with better functional status after injury.

Cognitive rehabilitation with right hemifield eye-patching for patients with sub-acute stroke and visuo-spatial neglect: A randomized controlled trial

Abstract Objective: To assess whether, following a right-hemisphere stroke, the combined administration of computer-based cognitive rehabilitation and right hemifield eye-patching in patients with visuo-spatial neglect is more effective than computer-based cognitive rehabilitation alone. Methods: Twelve patients were randomized into two treatment groups: a single treatment group (n = 7) and a combination treatment group (n = 5). In both cases, the treatment consisted of a mean number of 15 sessions, each lasting 1 hour. Visuo-spatial neglect was assessed using a specific exploration protocol (Bell Cancellation Test, Figure Copying of Odgen, Line Bisection, Baking Tray Task and Reading Task). The functional effects of the treatment were assessed using the Catherine Bergego Scale. Results: Significant between-group differences were observed when comparing the pre- and post-treatment scores for the Reading Task. No differences were observed in either group in the Catherine Bergego Scale administered at baseline and at the final intervention. Conclusion: The results obtained do not allow one to conclude that the combination treatment with cognitive rehabilitation and right hemifield eye-patching is more effective than cognitive rehabilitation alone. Although partial improvement in the performance of neuropsychological tests was observed, this improvement is not present at functional level.

Combination treatment in the rehabilitation of visuo-spatial neglect.

BACKGROUND Visuo-spatial neglect predicts longer hospitalization, poorer recovery of motor skills and greater functional limitation. The aim of the present study was to analyze whether the combined administration of computerized cognitive rehabilitation with right hemifield eye-patching in patients with left spatial neglect following a right hemisphere stroke is more effective than computerized cognitive rehabilitation applied in isolation. METHOD Randomized clinical trial conducted in 28 patients. These were grouped into two experimental groups: single treatment group (ST) (n= 15) and combined treatment group (CT) (n= 13). All received an average of 15 one-hour sessions of computerized cognitive rehabilitation using the Guttmann, NeuroPersonalTrainer® telerehabilitation platform. Those patients in the TC group performed the sessions wearing a visual device with which the right hemifield of each eye was occluded. RESULTS Following treatment, both the ST and the TC group showed improvements in neuropsychological examination protocol although there were no differences pre- and post-treatment on the functional scale in either group. Likewise, no statistically significant differences were observed in intergroup comparison. CONCLUSIONS The results from this study indicate that combination treatment is not more effective than rehabilitation applied in isolation.

La integración en la comunidad como medida de resultado de la neurorrehabilitación en el traumatismo craneoencefálico

Resumen Introduccion Los traumatismos craneoencefalicos (TCE) afectan principalmente a personas jovenes, ocasionando alteraciones fisicas, cognitivas, conductuales y socials que pueden limitar al sujeto en sus actividades incluso anos despues de la lesion. El objetivo ultimo de la neurorrehabilitacion es ayudar al paciente con TCE a reducir el impacto de las condiciones discapacitantes, facilitando que logre niveles optimos de funcionalidad. El objetivo de este estudio es describir el nivel de integracion comunitaria en pacientes con TCE moderado o grave entre 2 y 5 anos despues del traumatismo. Pacientes y metodos La muestra estaba formada por 73 pacientes con TCE moderado o grave (edad media: 30,7 [desviacion estandar: 13,7 anos]). La integracion comunitaria se valoro entre 2 y 5 anos despues del tratamiento neurorrehabilitador utilizando una adaptacion del Community Integration Questionnaire. Resultados El 66,5 % de los pacientes eran independientes para las actividades basicas de la vida diaria, el 76,7 % participaban en actividades de ocio y un 38,7 % volvieron a trabajar despues del TCE. Conclusiones Los pacientes con TCE pueden mostrar, anos despues de la lesion, limitaciones en su reintegracion social y laboral. Si bien en neurorrehabilitacion la reinsercion laboral del paciente es utilizada ampliamente como medida de los resultados del tratamiento, es necesario incorporar otras variables como el nivel de integracion comunitaria.

A customized home-based computerized cognitive rehabilitation platform for patients with chronic-stage stroke: study protocol for a randomized controlled trial

BackgroundStroke patients usually suffer primary cognitive impairment related to attention, memory, and executive functions. This impairment causes a negative impact on the quality of life of patients and their families, and may be long term. Cognitive rehabilitation has been shown to be an effective way to treat cognitive impairment and should be continued after hospital discharge. Computerized cognitive rehabilitation can be performed at home using exercise programs that advance with predetermined course content, interval, and pace. We hypothesize that computerized rehabilitation might be improved if a program could customize course content and pace in response to patient-specific progress. The present pilot study is a randomized controlled double-blind crossover clinical trial aiming to study if chronic stroke patients with cognitive impairment could benefit from cognitive training through a customized tele-rehabilitation platform (“Guttmann, NeuroPersonalTrainer”®, GNPT®).Methods/designIndividuals with chronic-stage stroke will be recruited. Participants will be randomized to receive experimental intervention (customized tele-rehabilitation platform, GNPT®) or sham intervention (ictus.online), both with the same frequency and duration (five sessions per week over 6 weeks). After a washout period of 3 months, crossover will occur and participants from the GNPT® condition will receive sham intervention, while participants originally from the sham intervention will receive GNPT®. Patients will be assessed before and after receiving each treatment regimen with an exhaustive neuropsychological battery. Primary outcomes will include rating measures that assess attention difficulties, memory failures, and executive dysfunction for daily activities, as well as performance-based measures of attention, memory, and executive functions.DiscussionCustomized cognitive training could lead to better cognitive function in patients with chronic-stage stroke and improve their quality of life.Trial registrationNCT03326349. Registered 31 October 2017.

Visual search in unilateral spatial neglect: The effects of distractors on a dynamic visual search task

ABSTRACT The objective of this study was to examine visual scanning performance in patients with Unilateral Spatial Neglect (USN) in a visual search task. Thirty-one right hemisphere stroke patients with USN were recruited. They performed a dynamic visual search task with two conditions, with and without distractors, while eye movements were monitored with an eye-tracker. The main goal of the task was to select target stimuli that appeared from the top of the screen and moved vertically downward. Target detection and visual scanning percentage were assessed over two hemispaces (right, left) on two conditions (distractor, no distractor). Most Scanned Regions (MSR) were calculated to analyze the areas of the screen where most points of fixation were directed to. Higher target detection rate and visual scanning percentages were found on the right hemispace on both conditions. From the MSRs we found that participants with a center of attention further to the right of the screen also presented smaller overall MSRs. Right hemisphere stroke patients with USN presented not only a significant rightward bias but reduced overall search areas, implying hyperattention does not only restrict search on the horizontal (right-left) axis but the vertical axis (top-bottom) too.