RESUMEN
A 51-year-old woman developed subacute progressive gait and cognitive difficulties, with depression and anxiety. She had psychomotor slowing, axial rigidity, fixed dystonic posturing of right hand and symmetrical generalised bradykinesia. MR brain scan identified bilateral multifocal non-enhancing high signal intensity in the frontal subcortical and periventricular areas, with corpus callosal thinning and areas of paraventricular diffusion restriction, suggesting an adult-onset leukodystrophy. Genetic analysis identified a heterogenous pathogenic variant in the colony-stimulating factor 1 receptor (CSF1R) causing this autosomal dominant leukoencephalopathy (OMIM 221820). The patient was unusual in having a CSF1R-related leukoencephalopathy without a relevant family history.
RESUMEN
While visuospatial deficits are well-characterized cognitive sequelae of right hemisphere (RH) stroke, apraxic deficits in RH stroke remain poorly understood. Likewise, very little is known about the association between apraxic and visuospatial deficits in RH stroke or about the putative common or differential pathophysiology underlying these deficits. Therefore, we examined the behavioural and lesion patterns of apraxic deficits (pantomime of object use and bucco-facial imitation) and visuospatial deficits (line bisection and letter cancellation tasks) in 50 sub-acute RH stroke patients. Using principal component analysis (PCA), we characterized the relationship between the two deficits. We hypothesized that any interaction of these neuropsychological measures may be influenced by the demands of ego-centric/space-based and/or allo-centric/object-based processing. Contralesional visuospatial deficits were common in our clinically representative patient sample, affecting more than half of RH stroke patients. Furthermore, about one-third of all patients demonstrated apraxic deficits. PCA revealed that pantomiming and the imitation of bucco-facial gestures loaded clearly on a first component (PCA1), while letter cancellation loaded heavily on a second component (PCA2). For line bisection, overall mean deviation loaded on PCA1, while the difference between the mean deviations in contra- versus ipsilesional space loaded on PCA2. These results suggest that PCA1 represents allo-centric/object-based processing and PCA2 ego-centric/space-based processing. This interpretation was corroborated by the statistical lesion analyses with the component scores. Data suggest that disturbed allo-centric/object-based processing contributes to apraxic pantomime and imitation deficits in (sub-acute) RH stroke.
Asunto(s)
Apraxias/fisiopatología , Accidente Cerebrovascular/fisiopatología , Percepción Visual/fisiología , Adulto , Anciano , Anciano de 80 o más Años , Mapeo Encefálico , Comprensión , Femenino , Lateralidad Funcional/fisiología , Gestos , Humanos , Procesamiento de Imagen Asistido por Computador , Conducta Imitativa/fisiología , Masculino , Persona de Mediana Edad , Pruebas NeuropsicológicasRESUMEN
It is debated how language and praxis are co-represented in the left hemisphere (LH). As voxel-based lesion-symptom mapping in LH stroke patients with aphasia and/or apraxia may contribute to this debate, we here investigated the relationship between language and praxis deficits at the behavioral and lesion levels in 50 sub-acute stroke patients. We hypothesized that language and (meaningful) action are linked via semantic processing in Broca's region. Behaviorally, half of the patients suffered from co-morbid aphasia and apraxia. While 24% (n = 12) of all patients exhibited aphasia without apraxia, apraxia without aphasia was rare (n = 2, 4%). Left inferior frontal, insular, inferior parietal, and superior temporal lesions were specifically associated with deficits in naming, reading, writing, or auditory comprehension. In contrast, lesions affecting the left inferior frontal gyrus, premotor cortex, and the central region as well as the inferior parietal lobe were associated with apraxic deficits (i.e., pantomime, imitation of meaningful and meaningless gestures). Thus, contrary to the predictions of the embodied cognition theory, lesions to sensorimotor and premotor areas were associated with the severity of praxis but not language deficits. Lesions of Brodmann area (BA) 44 led to combined apraxic and aphasic deficits. Data suggest that BA 44 acts as an interface between language and (meaningful) action thereby supporting parcellation schemes (based on connectivity and receptor mapping) which revealed a BA 44 sub-area involved in semantic processing.