Visual form-processing deficits: a global clinical classification.

INTRODUCTION: Patients who have difficulties recognising visual form stimuli are usually labelled as having visual agnosia. However, recent studies let us identify different clinical manifestations corresponding to discrete diagnostic entities which reflect a variety of deficits along the continuum of cortical visual processing. DEVELOPMENT: We reviewed different clinical cases published in medical literature as well as proposals for classifying deficits in order to provide a global perspective of the subject. Here, we present the main findings on the neuroanatomical basis of visual form processing and discuss the criteria for evaluating processing which may be abnormal. We also include an inclusive diagram of visual form processing deficits which represents the different clinical cases described in the literature. Lastly, we propose a boosted decision tree to serve as a guide in the process of diagnosing such cases. CONCLUSIONS: Although the medical community largely agrees on which cortical areas and neuronal circuits are involved in visual processing, future studies making use of new functional neuroimaging techniques will provide more in-depth information. A well-structured and exhaustive assessment of the different stages of visual processing, designed with a global view of the deficit in mind, will give a better idea of the prognosis and serve as a basis for planning personalised psychostimulation and rehabilitation strategies.

[Mild cognitive impairment: early detection and new perspectives]. / Deterioro cognitivo leve: deteccion temprana y nuevas perspectivas.

INTRODUCTION. Along past years, interest in mild cognitive impairment (MCI) research and its early detection has been increased. Unlike first theories, international current proposals suggest that MCI is a syndrome characterized by an impairment in one or more cognitive functions without interfering in daily functional abilities and it is also accompanied by a concern because of the cognitive change. Although early MCI detection is usually made by cognitive screening tests, most of them do not seem to correctly detect MCI, but dementia. AIM. To expose an analysis of the cognitive screening tests more suitable for clinical MCI detection, according to current researches. DEVELOPMENT AND CONCLUSIONS. There are three kind of cognitive screening tests: general cognitive screening tests, specific cognitive screening tests and MCI-subtype cognitive screening test. We observe that most of the tests don't follow current MCI criteria. In this respect we propose to jointly apply tests, as well as the necessity of a carefully test choice to effectively detect MCI in clinical practice.

[Long-term cognitive deficits in patients operated on for cerebral aneurysm by craniotomy and clipping]. / Déficits cognitivos a largo plazo en pacientes intervenidos de un aneurisma cerebral mediante craneotomía y clipaje.

INTRODUCTION: An important number of patients continue to present cognitive disorders after cerebral aneurysm surgeries, not only within the acute phase but also years after the subarachnoid hemorrhage and in spite of their good functional recovery. GOALS: The percentage of patients who continues to present cognitive alterations after 4 years of cerebral aneurysm surgery is studied within a sample of people who had pterional craniotomy and ICA clipping (Intracranial Aneurysm Clips). The repercussions on their daily life activities and quality of life are also considered and we analyze how are these deficits related to the cerebral location of the aneurysm. SAMPLE AND METHOD: Twenty-nine adults of both sexes, without cognitive disorder or psychiatric precedents who had an aneurysm surgery in different cerebral locations. RESULTS AND CONCLUSIONS: All the patients were independent in their daily life activities. The majority of the patients had good neurological resolution four years after the surgery and their cognitive performances were within the normality. Nevertheless, there is a small group that continues to present cognitive performances below what was expected for their age and educational level. The performances in cognitive tasks of attention, temporalspatial orientation, visual naming, memory, auditory verbal learning, visual-constructive skills and executive function do not depend on the cerebral location of the aneurysm.

[Mnemonic performance in patients following surgery to treat an aneurysm affecting the anterior circulation of the brain]. / Rendimientos mnésicos en pacientes intervenidos de un aneurisma de la circulación cerebral anterior.

INTRODUCTION: Patients submitted to surgery to treat a brain aneurysm, who have suffered a subarachnoid haemorrhage, sometimes present cognitive disorders that can affect their social, familial, academic or occupational relationships. Memory disorders are frequent, although other cognitive functions may also be affected. AIMS: The purpose of this research work was to study performance in logical verbal memory and visual-constructional memory in subjects following a surgical intervention (at least a year ago) to treat an aneurysm in the territory of the anterior circulation of the brain. We also wanted to analyse whether the location of the aneurysm in the brain had any effect on memory performance. PATIENTS AND METHODS: We examined a sample of 24 adult subjects of both sexes, with no previous history of cognitive or psychiatric disorders, who had undergone surgical treatment of brain aneurysms in the middle cerebral, anterior communicating and posterior communicating arteries. Neuropsychological tests were performed to assess the general cognitive status, as well as logical verbal and visual-constructional memory. RESULTS: 79% of the patients present a general cognitive status within the range of what could be considered to be normal. In logical verbal memory, 92% present performances within the limits of the expected range of values and 83% did the same in visual-constructional memory. Depending on the location of the aneurysm, significant differences were only found in the delayed evocation of logical verbal material. CONCLUSIONS: A year after the intervention, most of the patients present a pattern of normality in the general cognitive status, and in logical verbal and visual-constructional memory. Yet, in spite of the good neurological resolution, alterations to memory are still to be found, although less frequently. The anatomical location of the aneurysm in the brain affects performance in tasks involving delayed logical verbal memory.

[Neurofunctional aspects of the thalamus]. / El talamo: aspectos neurofuncionales.

AIM: To carry out a revision of the principal neurofunctional aspects of the thalamus. DEVELOPMENT: Following the anatomical location of this cerebral structure in the diencephalon, we'll analyze the macroscopic characteristics of the thalamus establishing its anatomical limits. We'll study the main thalamic nuclei, taking into account different criteria: evolution, anatomical and functional, cytoarchitectonic, and connective fibers as well as the principal projections which reach and leave the thalamus, allowing an adequate information processing. The last part of this paper is dedicated to study of the aspects related with the participation of the thalamus in the basic psychofunctional processes and superior processes. CONCLUSIONS: The thalamus, in addition to its implication along with the cerebral cortex in the analysis and integration of sensitive and motor functions, is implied in superior functions like the attention, language, memory and executive function. The pulvinar nucleus, the lateral nuclear group and the anterior nuclear group take part in the language, fundamentally. In the mnesic processes, the scientific studies show that the midline nuclei, mediodorsal thalamic nuclei and intralaminar nuclei of the thalamus are implied in this superior function. Lesions of the thalamus can cause alterations in the executive functions, attention, initiative and temporal organization of the conduct. The mediodorsal nuclei, the intralaminar nuclei and the midline nuclei has been shown to have a critical role in executive function.

[Mnemonic performance in mild traumatic brain injury]. / Rendimientos mnésicos en el traumatismo craneoencefálico leve.

INTRODUCTION: Over the past few years there has been a lot of discussion over whether the mnemonic disorders that can appear after a mild traumatic brain injury (TBI) present as transitory deficits or can remain as permanent sequelae. AIMS: To study whether there are mnemonic disorders in mild TBI or not, and to examine their evolution over the first year. PATIENTS AND METHODS: 60 adult subjects of both sexes with mild TBI, all of whom satisfied the criteria of the Mild Traumatic Brain Injury Interdisciplinary Special Interest Group of the American Congress of Rehabilitation Medicine, were studied at four different moments of their evolution (during the first seven days, at one month, at six months and at one year after the traumatism). The sample was completed with 60 normal adult subjects who shared similar demographic characteristics. MATERIAL: clinical scales for measuring TBI, cognitive screening tests and neuropsychological mnemonic tests that measure verbal learning, immediate and delayed logical verbal memory, visuospatial and visuo constructive memory. STATISTICAL ANALYSIS: data were analysed using ANOVA of repeated measures and a posteriori testing using Scheffe F test. CONCLUSIONS: Memory was affected in these patients for at least the first week after the traumatic injury took place. At one month, immediate and delayed logical verbal memory and visuo constructive memory showed cognitive performances that were similar to the control group. Learning and the verbal auditory capacity to retain a list of words were still altered one year after the traumatic injury occurred.

[Post-traumatic amnesia syndrome]. / Síndrome amnésico postraumático.

INTRODUCTION: Mnesic deficits are frequent in subjects which have suffered from head injury and may persist during may years. OBJECTIVE: We will analyze posttraumatic amnesia characteristics (PTA) as well as learning and memory deficits which are normally observed once the PTA phase is over. DEVELOPMENT: The PTA is defined as the period that follows a brain injury in which the affected person is incapable of consistently remembering at least the last 24 hours. That is, the period after the head injury in which the incorporation of new information in long term memory is not possible. The study of PTA has generally been focussed on the analysis of the alterations of temporo-spatial orientation and mnesic deficits, however other cognitive and behavioral alterations do exist (linguistic, attentional, critical judgement, information processing, perception, etc.), and they are associated with the particular memory disorder that we are studying, given their influence on it. We will take on board the different theories that have been proposed to explain mnesic deficits which occur during the PTA phase: lack of consolidation of new information within longterm memory; recall deficit as a result of inefficient coding of information; failures of the mechanisms to carry out the process of consolidation-recall, and poor organization in the coding of new material. We will put forward a guide for the neuropsychological assessment of memory based on the analytic and concrete study of each mnesic cognitive component, sustained generally by specific neurophysiological functional systems which allow us to establish a diagnosis, prognosis, and adequate therapeutic focus for each concrete case.

[Neuropsychological assessment in posttraumatic amnesia disorder]. / Evaluación neuropsicológica en el síndrome amnésico postraumático.

INTRODUCTION: The neuropsychological evaluation of memory is an essential investigation in all patients with head injuries, since alterations occur in a high proportion of injured persons and are one of the commonest sequelae. OBJECTIVE: To analyse aspects of the neuropsychological evaluation of memory in head injuries, and the influence of other factors on memory. DEVELOPMENT: Regarding the study of memory capacity, other aspects relative to the presence or absence of posttraumatic amnesia (its characteristics and duration), lacunar-type disorders, retrograde amnesia, anterograde amnesia, ability to learn new information and the position of explicit and implicit memory should be considered. We analyze the instruments for measurement most commonly used for neuropsychological evaluation of memory in patients with head injuries, and the main batteries, tests and scales used for objective evaluation of the presence or absence of memory deficit. We review the main limitations and methodological problems presented by the tests and scales for measurement in this type of population. The instruments of measurement, except for those adapted for the detection of common alterations in head injuries often present serious problems when used to detect posttraumatic deficits. CONCLUSION: Clinically, evaluation of memory should show a profile of the patient's capacities, measure the changes in memory function over time, and predict memory function in everyday activities.