Análisis instrumental de la marcha en pacientes con ictus / Instrumental gait analysis in stroke patients

Introducción. Las alteraciones en el control motor consecuentes al ictus afectan al patrón de marcha, existiendo una importante variabilidad intersujeto. Objetivos. Valorar, a través de un sistema de captura del movimiento, el patrón cinemático de la marcha en sujetos con ictus y establecer qué alteraciones del patrón de la marcha son comunes entre los participantes. Sujetos y métodos. Participaron nueve pacientes con ictus con capacidad de marcha y diez sujetos controles. Para la captura del movimiento se empleó el sistema VICON Motion System (R). Se analizaron los movimientos articulares de pelvis, cadera, rodilla y tobillo en el plano sagital, y los parámetros espaciotemporales de la marcha. Resultados. La función motora de los participantes, valorada mediante la escala Fügl-Meyer (sección del miembro inferior), osciló entre 15 y 33 puntos. Los participantes presentaron alteraciones en la cinemática comunes entre ellos. En los pacientes con ictus se registró: aumento de la amplitud de movimiento de la pelvis en ambos hemicuerpos (lado afecto y no afecto frente a control, p < 0,01); en la cadera, disminución de la máxima extensión durante la fase de apoyo en el lado afecto (p < 0,01) e incremento de la flexión en las fases de apoyo y oscilación en el no afecto (p = 0,025); en la rodilla, mayor flexión durante la fase de contacto inicial (lado afecto frente a control, p < 0,01; lado no afecto frente a control, p = 0,02); y en el tobillo, ligera flexión plantar durante la fase de contacto inicial en el lado afecto. Conclusiones. A pesar de la variabilidad clínica, existen alteraciones específicas comunes de la marcha en sujetos con ictus (AU)

Introduction. The motor control deficits after stroke affect the gait pattern. There is a significant variability between subjects. Aims. To analyse, by using a capture motion system, the gait pattern in stroke patients with different levels of motor function, and to establish, despite the participants heterogeneity, what alterations in the gait pattern are usual in each participant. Subjects and methods. Nine stroke subjects with independent gait and ten control subjects participated in this study. Motion capture was performed using the VICON Motion System (R). The motion of the pelvis, hip, knee and ankle were analyzed in the sagittal plane. Also, the spatio-temporal parameters of gait were observed. Results. The motor function evaluated using the Fügl-Meyer Assessment (lower limb section) varied between 15 and 33 points. Participants had alterations in the kinematic pattern which were common between each of them. In stroke patients it was observed: an increment of the pelvis range of motion in both sides; at the hip joint, a decrease of the maximum peak of extension during the stance phase in the affected side and a greater flexion during the stance and the swing periods in the non-affected side; at the knee, a major knee flexion during the initial contact; and at the ankle joint, an slight ankle plantar flexion during the initial contact on the affected side. Conclusions. There are several landmarks in stroke gait that the clinicians should keep attention during the walking observation (AU)

Variability of writing disorders in Wernicke's aphasia underperforming different writing tasks: A single-case study.

The aim of our study was to evolve views on writing disorders in Wernicke's agraphia by comparing group data and analysis of a single patient. We showed how a single-case study can be useful in obtaining essential results that can be hidden by averaging group data. Analysis of a single patient proved to be important for resolving contradictions of the "holistic" and "elementaristic" paradigms of psychology and for the development of theoretical knowledge with the example of a writing disorder. The implementation of a holistic approach was undertaken by presenting the tasks differing in functions in which writing had been performed since its appearance in human culture (communicative, mnestic, and regulatory). In spite of the identical composition of involved psychological components, these differences were identified when certain types of errors were analyzed in the single subject. The results are discussed in terms of used writing strategy, resulting in a way of operation of involved components that lead to qualitative and quantitative changes of writing errors within the syndrome of Wernicke's agraphia.

Pathophysiology of language switching and mixing in an early bilingual child with subcortical aphasia.

Acquired aphasia after circumscribed vascular subcortical lesions has not been reported in bilingual children. We report clinical and neuroimaging findings in an early bilingual boy who incurred equally severe transcortical sensory aphasia in his first language (L1) and second language (L2) after a posterior left thalamic hemorrhage. Following recurrent bleeding of the lesion the aphasic symptoms substantially aggravated. Spontaneous pathological language switching and mixing were found in both languages. Remission of these phenomena was reflected on brain perfusion SPECT revealing improved perfusion in the left frontal lobe and left caudate nucleus. The parallelism between the evolution of language symptoms and the SPECT findings may demonstrate that a subcortical left frontal lobe circuity is crucially involved in language switching and mixing.

Nonfluent progressive aphasia and semantic dementia: a comparative neuropsychological study.

Two patients with nonfluent progressive aphasia, who have been studied longitudinally, are contrasted with a group of 5 patients with fluent progressive aphasia or semantic dementia. The most prominent feature of the nonfluent syndrome is the severe distortion of speech output with phonological errors and agrammatic sentence structure. This contrasts with the fluent, well articulated and syntactically correct, but empty, anomic speech found in semantic dementia. Performance on tests of comprehension separates the patient groups: The nonfluent patients show normal single-word comprehension, but marked impairment on tests of syntactic comprehension, while those with semantic dementia demonstrate the opposite pattern. Category fluency is severely defective in semantic dementia, but initial letter-based fluency is more impaired in the nonfluent syndrome. Performance on nonverbally mediated tests of semantic knowledge is impaired in semantic dementia only. The 2 forms of progressive aphasia have in common the sparing of perceptual and visuospatial skills, nonverbal problem solving abilities, and day-to-day (episodic) memory. Neuroradiological investigations have shown marked selective and striking inferolateral left temporal lobe atrophy in all 5 patients with semantic dementia. The changes in nonfluent progressive aphasia appear to be less focal and involve left perisylvian structures more diffusely. These 2 forms of progressive aphasia are, we argue, distinct in their manifestations.

Real-time examinations of lexical processing in aphasics.

We argue that the lesion localizing value of disruptions to modular information processing systems emerges most clearly from on-line analyses of processing. In this respect we seek to show that left anterior (but not left posterior) damage causes slowed information access and we discuss the manner in which this slowing might yield some of the specific syntactic limitations charted in Broca's aphasia. The general possibility we raise is that the cortical area implicated in Broca's aphasia is not necessarily the locus of syntactic representations, but rather sustains particular time-based operating characteristics that in turn sustain normal real-time parsing.

Transcortical sensory aphasia: evidence for subtypes.

Impaired auditory comprehension and fluent but semantically empty speech in conjunction with preserved repetition characterize the syndrome of transcortical sensory aphasia (TSA). Repetition, however, may be mediated by at least two distinct processes--a lexical process that may involve the recognition and subsequent activation of discrete stored word representations and a nonlexical process that involves phonologic decoding and immediate phonologic encoding from immediate memory. We investigated the spontaneous speech, reading, and tendency to recognize and spontaneously correct syntactic errors in four patients with TSA: this analysis suggests there are two subtypes of TSA. We contend that in one subtype both the lexical and direct repetition (or speech production) mechanisms are preserved, but in the second subtype the lexical mechanism is disrupted and repetition is mediated by the nonlexical mechanism.

Comparative classification of aphasic disorders.

This study compares aphasia classification of 20 aphasics who were evaluated with the Western Aphasia Battery (WAB) and the Lisbon Aphasia Examination Battery (LAEB). High correlations were found between tests evaluating the same functions in both batteries. Aphasia types derived from these two batteries showed only a partial overlap. This was due to the use of different numerical diagnostic criteria. When these criteria were used to specify aphasia types of 179 acute and 113 chronic aphasics grouped by cluster analysis, similar discrepancies were noted. Two major differences were found: some LAEB global aphasics turned out to be WAB Broca's and some LAEB anomics were classified as WAB conduction aphasics. These disagreements reflect difficulties in delimiting Broca's and conduction aphasia. The importance of the numerical approach to aphasia classification is stressed, as it is a reliable method to classify aphasic patients in order to allow comparison of data from different centers.