Vata-L: Visual-Analogue Test Assessing Anosognosia for Language Impairment

Lack of awareness (anosognosia) for one's own language impairments has rarely been investigated, despite hampering language rehabilitation. Assessment of anosognosia by means of self-report is particularly complex, as a patient's language difficulties may seriously prevent or bias the assessment. Other methods, such as measures of self-correction and error detection, have provided valuable information, although they are an indirect form of assessment of anosognosia and are not exempt from methodological criticisms. In this study we report on a new tool, the VATA-L (Visual-Analogue Test for Anosognosia for Language impairment), geared at assessing explicit anosognosia for aphasia. The VATA-L compares the patient's self-evaluation with caregivers’ evaluations of the patient's verbal communication abilities in a series of common situations. By means of non-verbal support and a system of check questions, this test minimizes some of the methodological limitations of existing diagnostic tools (e.g., structured interviews), enhancing reliability, and enabling assessment of patients with aphasia. Finally, normative data provided in the study allow a clearer interpretation of the patient's performance and facilitate assessment of anosognosia

The influence of color on snake detection in visual search in human children

It is well known that adult humans detect snakes as targets more quickly than flowers as the targets and that how rapidly they detect a snake picture does not differ whether the images are in color or gray-scale, whereas they find a flower picture more rapidly when the images are in color than when the images are gray-scale. In the present study, a total of 111 children were presented with 3-by-3 matrices of images of snakes and flowers in either color or gray-scale displays. Unlike the adults reported on previously, the present participants responded to the target faster when it was in color than when it was gray-scale, whether the target was a snake or a flower, regardless of their age. When detecting snakes, human children appear to selectively attend to their color, which would contribute to the detection being more rapidly at the expense of its precision

Effects of TMS on Different Stages of Motor and Non-Motor Verb Processing in the Primary Motor Cortex

The embodied cognition hypothesis suggests that motor and premotor areas are automatically and necessarily involved in understanding action language, as word conceptual representations are embodied. This transcranial magnetic stimulation (TMS) study explores the role of the left primary motor cortex in action-verb processing. TMS-induced motor-evoked potentials from right-hand muscles were recorded as a measure of M1 activity, while participants were asked either to judge explicitly whether a verb was action-related (semantic task) or to decide on the number of syllables in a verb (syllabic task). TMS was applied in three different experiments at 170, 350 and 500 ms post-stimulus during both tasks to identify when the enhancement of M1 activity occurred during word processing. The delays between stimulus onset and magnetic stimulation were consistent with electrophysiological studies, suggesting that word recognition can be differentiated into early (within 200 ms) and late (within 400 ms) lexical-semantic stages, and post-conceptual stages. Reaction times and accuracy were recorded to measure the extent to which the participants' linguistic performance was affected by the interference of TMS with M1 activity. No enhancement of M1 activity specific for action verbs was found at 170 and 350 ms post-stimulus, when lexical-semantic processes are presumed to occur (Experiments 1–2). When TMS was applied at 500 ms post-stimulus (Experiment 3), processing action verbs, compared with non-action verbs, increased the M1-activity in the semantic task and decreased it in the syllabic task. This effect was specific for hand-action verbs and was not observed for action-verbs related to other body parts. Neither accuracy nor RTs were affected by TMS. These findings suggest that the lexical-semantic processing of action verbs does not automatically activate the M1. This area seems to be rather involved in post-conceptual processing that follows the retrieval of motor representations, its activity being modulated (facilitated or inhibited), in a top-down manner, by the specific demand of the task

A functional model of visuo-verbal disconnection and the neuroanatomical constraints of optic aphasia

In this paper, we discuss the case of a patient, As, who presented a pattern of performance corresponding to that usually known as optic aphasia, In particular, her visual object naming was severely impaired, while tactile naming and naming to definition were significantly better. In addition to the classical visual anemia, the patient also showed a deficit in tasks requiring categorization and access to associative knowledge. We interpret the results of our patient in line with the explanation proposed by Coslett and Saffran (Brain, 1989; 112: 1091-110), i.e. a disconnection between right hemisphere and left hemisphere semantic knowledge. Damage to the left occipital region requires the initial processing of visual information to be carried out in the right hemisphere only, and a lesion of the splenium of the corpus callosum interrupts the flow of information from the right to the left hemisphere, However, the pattern of symptoms observed in our patient can only be fully explained by combining this framework with a model which distinguishes visual from verbal semantics (Shallice, 1988, From Neuropsychology To Mental Structure, Cambridge University Press), While the right hemisphere has a complete visual semantic organization, it has only a basic and concrete associative semantic representation. As's difficulties in categorizing and in accessing associative knowledge as the result of a visuo-verbal disconnection were also interpreted in this light, Furthermore, we suggest that the variable patterns of optic aphasia and the different behaviour of associative visual agnosic patients may be explained by interindividual differences in the levels of verbal and visual semantics in the right hemisphere

The neural bases of limb and oral apraxia: A VLSM study in a cohort of left-hemisphere brain-damaged patients

Introduction : Notwithstanding the high number of experimental studies examining limb and oral apraxia from a clinical, cognitive (Tessari et al., 2004) and neuroimaging point of view, the neural mechanisms underlying this impairment are still little clarified. Motor programming abilities have been recently investigated with f-MRI techniques (Martin et al., 2016) but lesions-to-symptoms mapping is still a fundamental method to underpin the anatomical basis of complex behaviors (Goldenberg et al., 2015). The aim of the present study is to investigate the anatomical basis of ideomotor, ideational, and oral apraxia in a cohort of left-hemisphere brain-damaged patients using the subtraction and voxel-based lesion-symptom mapping (VLSM) localization procedures. Methods : Ideomotor (arm and hand movements vs. finger movements), ideational and oral apraxia were studied through an anatomo-clinical correlative procedure in a sample of 48 left-hemisphere brain-damaged patients. Subtraction and VLSM procedures were used to localize the anatomical bases of these impairments. Results : Lesions of the left supramarginal gyrus and of the left angular gyrus were associated with ideomotor apraxia of the upper limb and hand; lesions of the left supramarginal gyrus and of the left middle frontal gyrus were associated with ideomotor apraxia of finger movement. Ideational apraxia was associated with lesions of the left supramarginal gyrus, left middle frontal gyrus and left inferior frontal gyrus (pars opercularis) suggesting a partial common neural substrate with ideomotor apraxia. A network of left perisylvian areas did emerge as anatomical correlate of oral apraxia, including the left insular cortex, and the left frontal and central opercula, the left inferior frontal gyrus (pars opercularis). Discussion : Our results confirm the existence of relatively independent anatomical specializations in the left hemisphere (Basso et al., 1985; Mengotti et al., 2015), with regards to the hierarchical level of limb apraxia (ideational vs. ideomotor), body parts (upper limb and hand vs. finger movements), and of oral apraxia (Tognola & Vignolo, 1980). References : Goldenberg G. Neuropsychologia (2015) 75: 40-49. Martin M. Brain (2016) 139: 1497-1516. Mengotti P. Neuropsychologia (2015) 79: 256-27

Lemma Theory and Aphasiology.

3nonenoneSEMENZA C.; LUZZATTI C .; MONDINI S.Semenza, Carlo; Luzzatti, C. .; Mondini, S

Reading in neurodegenerative diseases: different impairments?

It is well known that neurodegenerative diseases may affect different areas of the brain, thereby giving rise to different patterns of cognitive deficits. We investigated reading performance in patients suffering from Alzheimer’s Disease (AD, n=19), Primary Progressive Aphasia (PPA, n=6: 4 logopenic, 1 semantic and 1 purely anomic aphasia) and Posterior Cortical Atrophy (PCA, n=4), plus a control group of healthy subjects (n=20). Participants were examined by means of tasks of auditory and visual lexical decision, word and non-word reading, reading trisyllabic words with unpredictable stress position (Toraldo et al, 2006) and word and non-word repetition. The lexical decision tasks proved relevant to differentiate AD and PCA patients, the former being disproportionately impaired in the auditory task while the opposite pattern emerged in the latter. Non-word reading was more impaired with respect to word reading in both AD and PPA patients. A multiple single case analysis of reading tasks identified phonological dyslexia in two out of four PCA participants (50%), much less so in AD (15.8%) and PPA (16.7%). Surface dyslexia occurred in one AD case only. We suggest that these results may be related to the different distribution of pathological changes in the three groups