Brain regions underlying repetition and auditory-verbal short-term memory deficits in aphasia: Evidence from voxel-based lesion system mapping

The goal of this study was to identify the neural correlates of repetition and a related process, auditory-verbal short-term memory (AVSTM). Both repetition and 15 AVSTM involve common elements such as auditory and phonological analysis and translation to speech output processes. Based on previous studies, we predicted that both repetition and AVSTM would be most dependent on posterior language regions in left temporo-parietal cortex

Voxel-based lesion analysis of brain regions underlying reading and writing

Contains fulltext : 191983pre.pdf (preprint version ) (Open Access)The neural basis of reading and writing has been a source of inquiry as well as controversy in the neuroscience literature. Reading has been associated with both left posterior ventral temporal zones (termed the "visual word form area") as well as more dorsal zones, primarily in left parietal cortex. Writing has also been associated with left parietal cortex, as well as left sensorimotor cortex and prefrontal regions. Typically, the neural basis of reading and writing are examined in separate studies and/or rely on single case studies exhibiting specific deficits. Functional neuroimaging studies of reading and writing typically identify a large number of activated regions but do not necessarily identify the core, critical hubs. Last, due to constraints on the functional imaging environment, many previous studies have been limited to measuring the brain activity associated with single-word reading and writing, rather than sentence-level processing. In the current study, the brain correlates of reading and writing at both the single- and sentence-level were studied in a large sample of 111 individuals with a history of chronic stroke using voxel-based lesion symptom mapping (VLSM). VLSM provides a whole-brain, voxel-by-voxel statistical analysis of the role of distinct regions in a particular behavior by comparing performance of individuals with and without a lesion at every voxel. Rather than comparing individual cases or small groups with particular behavioral dissociations in reading and writing, VLSM allowed us to analyze data from a large, well-characterized sample of stroke patients exhibiting a wide range of reading and writing impairments. The VLSM analyses revealed that reading was associated with a critical left inferior temporo-occipital focus, while writing was primarily associated with the left supramarginal gyrus. Separate VLSM analyses of single-word versus sentence-level reading showed that sentence-level reading was uniquely associated with anterior to mid-portions of the middle and superior temporal gyri. Both single-word and sentence-level writing overlapped to a great extent in the left supramarginal gyrus, but sentence-level writing was associated with additional underlying white matter pathways such as the internal capsule. These findings suggest that critical aspects of reading and writing processes diverge, with reading relying critically on the ventral visual recognition stream and writing relying on a dorsal visuo-spatial-motor stream.9 p

A new test battery to assess aphasic disturbances and associated cognitive dysfunctions - German normative data on the Aphasia Check List

Kalbe E, Reinhold N, Brand M, Markowitsch HJ, Kessler J. A new test battery to assess aphasic disturbances and associated cognitive dysfunctions - German normative data on the Aphasia Check List. JOURNAL OF CLINICAL AND EXPERIMENTAL NEUROPSYCHOLOGY. 2005;27(7):779-794.Aphasia, defined as an acquired impairment of linguistic abilities, can be accompanied by a diversity of neuropsychological dysfunction. Accordingly, the necessity to include cognitive testing in the diagnosis of aphasia is increasingly recognized (Helm-Estabrooks, 2002). Here we present the Aphasia Check List (ACL), a new test battery for the assessment of aphasic and associated cognitive disorders. The language part of the battery provides a differentiated profile of important linguistic abilities. In addition, the ACL includes nonverbal screening tests for three neuropsychological domains: memory, attention, and reasoning. Dysfunctions in these domains have been observed in aphasic patients and can have an impact on language function. The ACL is applicable to patients with language disturbances of different etiologies, different stages of disease, and to patients with mild to severe aphasia. As the entire test duration is only about 30 minutes, the ACL is also economically valuable. It thus presents an adequate starting point in aphasia diagnosis for a wide range of patients. Here we describe the construction of the ACL, and the normative study of its original German version with 154 aphasic patients and 106 healthy comparison subjects. The ACL cognition part revealed additional neuropsychological dysfunction in the aphasia group. We present the patterns of these dysfunctions and their correlations with language deficits