[Show abstract][Hide abstract] ABSTRACT: Objective: In cortical deafness, no auditory signals can be perceived by the cortex despite normal peripheral hearing. Cortical deafness rarely persists, but generally evolves into other cortical auditory syndromes. In this report, we describe a patient showing a stable and persisting pattern of cortical deafness 16 months after two major ischemic strokes. Methods: Voxel based morphometric evidence from high resolution three-dimensional MRI and data from tractography are reported for the first time, to our knowledge, in this syndrome in addition to behavioral and electrophysiological findings. Results: The most remarkable findings came from the tractography data, where an asymmetric pattern was found showing severe damage of connections within the anterior right hemisphere, in regions subserving self-awareness. Frontal asymmetry, although detectable by the morphometric analysis, was less informative than that detected in the tractography data. Conclusion: The evidence from this case study suggests that damage to the neural systems involved in awareness may play an important role in the emergence of cortical deafness and its persistence. (PsycINFO Database Record (c) 2012 APA, all rights reserved).
[Show abstract][Hide abstract] ABSTRACT: The effect of transcranial direct current stimulation (tDCS) and repetitive transcranial magnetic stimulation (rTMS) on psychopathological symptoms and resting state brain activity was assessed in a patient with obsessive-compulsive disorder (OCD). tDCS and rTMS had no effect on OC symptoms. tDCS, however, improved depression and anxiety. Functional magnetic resonance imaging at baseline showed an interhemispheric asymmetry with hyperactivation of the left and hypoactivation of the right anterior neural circuits. A reduction of interhemispheric imbalance was detected after tDCS but not after rTMS. tDCS seems to be more effective than rTMS in restoring interhemispheric imbalance and improving anxiety and depression in OCD.
[Show abstract][Hide abstract] ABSTRACT: The aim of this study was to determine the brain areas responsible for the semantic impairment observed in Alzheimer’s disease (AD) and Mild Cognitive Impairment (MCI) patients. Thirteen AD, 14 MCI patients, and 13 matched healthy older adults were assessed with a test battery aimed to study their semantic competence. Different subtasks were designed to study their semantic knowledge related to objects and faces in the context of semantic retrieval- and semantic association-dependent tasks. Aggregate scores obtained in the different tests were entered into voxel-based regression analyses with grey matter volume values obtained from three-dimensional brain MRI scans. Areas of significant correlation between volume loss and poor semantic scores were restricted to the temporal lobe in the AD group, while in the MCI and control groups significant associations were found with lower grey matter volume values in a widely distributed network of bilateral fronto-temporo-parietal regions. Our results suggest that degradation of partially overlapping and widely distributed neural networks, mainly including temporal regions, subserve semantic deficits related to objects and faces in AD and MCI patients.
Journal of Neurolinguistics 05/2012; · 1.60 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: When assessing for the presence of hemianesthesia, the examiner touches the body of the patients, and requests that they report verbally the location of the delivered tactile stimulus. Contralesional omissions of single tactile stimuli, however, might be due to either primary somatosensory deficits or to spatial attention impairment (i.e., neglect). In this preliminary study, we tested whether clinical assessment can be improved to differentiate between these two types of deficit by modifying the assessment procedure. K.L., a patient with left unilateral neglect, was asked to detect tactile stimuli delivered in two conditions: spatial attention distributed either to his left or to his right hand, and spatial attention focused only on his left hand. Note that K.L. did not receive double simultaneous tactile stimuli. In the distributed spatial attention condition, K.L. omitted most of the single tactile stimuli delivered to his left hand. In the focused attention condition, K.L. was asked to focus his spatial attention only on his left hand. Under this latter condition, his performance increased dramatically, suggesting that his omissions were not due to hemianesthesia, but rather reflected left tactile neglect. In line with the neuropsychological findings, voxel based analysis of his grey and white matter damage confirmed significant loss in areas associated with left-sided neglect, but sparing of primary somatosensory cortex. This result suggests that standard somatosensory assessment and differential diagnosis between hemianesthesia and tactile neglect may be more accurate when neuropsychology-based procedures are incorporated in the standard neurological examination.
[Show abstract][Hide abstract] ABSTRACT: Introduction: Patients with unilateral neglect may show line bisection errors selectively in either near (within hand reaching) or far (beyond hand reaching) space which suggests that these two spatial areas are coded differently by the brain. This exploratory study investigated, whether any difference in performance between these spatial domains might be task-independent or modulated by the requirement for a motor response.Methods: A 31-year-old right brain damaged patient (MF) and a group of age matched healthy controls were assessed with two serial visual search tasks and a Landmark paradigm. Both types of task required either a directional (pointing) or non-directional (button press) motor response. Participants were assessed with both task types and response modes in near (57 cm) and far space (114 cm). Results: MF showed left neglect during visual search only in far space for the perceptual condition and in near space for the motor condition. MF showed no neglect in both versions of the Landmark task irrespective of spatial distance. A voxel-based morphometric assessment of MF's brain lesion showed marked damage in the right ventro-temporal cortex, superior temporal gyrus, insula, inferior frontal gyrus, angular gyrus and bilaterally in the posterior cingulate cortex. Conclusions: Our preliminary findings suggest that processing of far space during visual search is associated with ventral stream damage but only when space is coded through visual information. Neglect involving directional motor activity in near space seems to be associated with damage of structures sharing close connections with the dorsal stream.
[Show abstract][Hide abstract] ABSTRACT: This is the case report of RB, a 68-year-old retired woman who, following an extensive right sided ischaemic stroke, showed hemiplegia, anosognosia and allochiria, but no somato-sensory deficits and no visuospatial neglect. A high resolution 3D MRI structural scan of her brain was acquired to define the structural damage in detail. Morphometric analyses of grey and white matter data revealed a large lesion which involved most of her right parietal, temporal, and mesial frontal cortex, with partial sparing of the right dorsolateral prefrontal cortex and part of the posterior corpus callosum. Detailed examination showed that RB attributed sensory stimuli, both on the left and on the right, to the opposite side of her body. This mirror reversed representation of her body caused misattribution of items even in the absence of stimulation, as for instance when the patient spontaneously reported pain in her right knee while pointing to her left knee. RB's neuropsychological profile showed normal or borderline performance on most cognitive tasks. Language comprehension was intact and she could tell left from right without difficulty in all instances except for those referable to her soma. To our knowledge this is the first description of severe allochiria for body representation in the absence of neglect. The evidence from this case supports the developing concept that the body representation is not simply a systematic registration of proprioceptive inputs, but that the brain has a more sophisticated high level representation of one's body map which is updated on the basis of multimodal information.
[Show abstract][Hide abstract] ABSTRACT: Most group studies which have investigated neglect for near and far space have found an increased severity of symptoms in far space compared to near space. However, the majority of these studies used relatively small samples and based their findings almost exclusively on line bisection performance. The aim of the present study was, therefore, to explore the occurrence of neglect for near and far space in a larger group of unselected right brain damaged patients and to evaluate whether neglect specific to near and far space is a task-related deficit or generalises across distance irrespective of task. In addition, a lesion overlap analysis was carried out to identify critical lesion sites associated with distance specific neglect deficits. Thirty-eight right hemisphere damaged patients carried out a line bisection and a cancellation task by using a pen in near space (40 cm) and a laser pointer in far space (320 cm). The results showed that both the number of left-sided omissions and rightward bisection errors were significantly increased in near compared to far space. Distance specific dissociations, albeit less common, were more frequently observed for cancellation than line bisection. These results suggest that space representation in neglect is more severely impaired in near than in far space. In addition, distance related dissociations in neglect may depend on task demands. Although the anatomical findings were broadly consistent with a dorsal and ventral stream dichotomy for near and far space processing, they also suggest the involvement of intermediate structures in distance related neglect phenomena.
[Show abstract][Hide abstract] ABSTRACT: Introduction
Episodic memory impairment is an early indicator in Alzheimer’s Disease (AD). Contrastingly, episodic memory is said to be substantially preserved in Frontotemporal dementia (FTD) especially in the early stages of the disease. Nevertheless, recent studies (e.g., Ivaniou et al, 2006) have suggested that the neurodegenerative process in FTD involves hippocampal structures, indicating that impairment in episodic memory, whilst being less severe than that seen in AD, is expected in FTD patients.
We assessed the neuropsychological test performance of 15 patients with AD and 15 patients with FTD. Both groups were matched for severity of cognitive decline, age and education.
Specifically, episodic memory was tested and compared with a paired associates learning (PAL) task and a prose memory task (immediate and delayed (10 minutes) recall). We further analysed the story units and thematic elements recalled by both groups on the prose memory task.
The overall neuropsychological assessment showed typical profiles in both patient groups. Detailed analysis of the episodic memory tasks showed abnormal scores in both groups, although scores of FTD patients were higher than those of the AD group, both at immediate and delayed recall. FTD patients performed better on thematic element recall than story unit recall, while the AD patients showed the opposite pattern. A similar pattern of deficits was also seen in both groups in the PAL test scores.
The results indicate that FTD patients do present with an episodic memory deficit, which is, however, less severe than that seen in AD patients. The pattern of impairments is however similar and in FTD does not seem to reflect frontal dysfunction since FTD patients, despite poor recall of story units, were still able to organise information sufficiently and recalled a greater number of thematic elements than AD patients.
[Show abstract][Hide abstract] ABSTRACT: A number of neuroimaging studies have shown that drug addiction is associated with morphological differences in several brain areas, including orbito-frontal and limbic structures. Most of these studies have investigated patients with addiction to cocaine. The neurobiological mechanisms which play a role in drug addiction are not fully understood, however, and the causal factors remain under investigation. The present study investigated morphological differences between patients with history of cocaine (N=14) and heroin (N=24) abuse and healthy matched controls (N=24). A 3D T1W MRI scan was acquired for all participants and the grey matter images of each patient group compared with those of controls. A direct comparison of the two addiction groups was also carried out. When compared with controls cocaine dependent patients had lower grey matter values in the left middle occipital gyrus, right putamen and insula, whereas heroin abusers had lower grey matter values in the right insula. The direct comparison between the two addiction groups showed that cocaine abusers had less grey matter in the right posterior cingulate, medio-temporal and cerebellar regions, whereas heroin abusers showed less grey matter in parietal regions on both sides, including postcentral gyrus and inferior parietal lobule. Reduced right posterior insular cortex was commonly found in both cocaine and heroin dependent patients. This morphological difference might represent a structural marker of addiction, which is independent of the discrete regional effects of each psychotropic substance of abuse, and might constitute a possible neurobiological vulnerability or diathesis to addiction. Equally, the discrete structural differences emerging from the direct comparison of cocaine and heroin abusers might reflect the effects of differential drug binding in the brain and/or express a form of neurobiological vulnerability which might explain individual drug choice.
Brain research bulletin 12/2011; 87(2-3):205-11. · 2.97 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: This functional Magnetic Resonance Imaging (fMRI) study investigated high and low suggestible people responding to two visual hallucination suggestions with and without a hypnotic induction. Participants in the study were asked to see color while looking at a grey image, and to see shades of grey while looking at a color image. High suggestible participants reported successful alterations in color perception in both tasks, both in and out of hypnosis, and showed a small benefit if hypnosis was induced. Low suggestible people could not perform the tasks successfully with or without the hypnotic induction. The fMRI results supported the self report data, and changes in brain activity were found in a number of visual areas. The results indicate that a hypnotic induction, although having the potential to enhance the ability of high suggestible people, is not necessary for the effective alteration of color perception by suggestion.
Consciousness and Cognition 11/2011; 21(1):100-16. · 2.31 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The Clock Drawing Test (CDT) is a valid screening tool for the evaluation of cognitive decline. This study aimed to compute standardized norms for the Freedman version of the CDT in a population of 248 healthy Italian individuals aged from 20 to 89 years.
The effects of age, education, and gender on performance were assessed. Three conditions were administered: free-drawn clock (FD), which required participants to draw the contour, numbers, hands, and center of the clock; predrawn clock (PD), in which numbers, hands, and center had to be included in a predrawn contour; examiner-drawn clock (ED), in which only hands and center had to be inserted in a template including a predrawn contour and numbers. Scores for each of the single conditions and a total score were calculated.
Age had no effect on the FD condition, whereas a significant effect of age was found for the PD and ED conditions and the total score. Gender and education had no influence on any of the scores. Correction grids, cutoffs, and equivalent scores were computed.
Standardized norms for the Freedman version of the CDT were collected in a large sample of healthy individuals. No adjustments were required for scores on the free-drawn condition, whereas raw scores on the predrawn and examiner-drawn conditions and the total score needed adjustments to account for age effects. The availability of standardized norms for this version of the CDT could increase the use of this comprehensive tool in the detection of dementia.
Journal of Clinical and Experimental Neuropsychology 11/2011; 33(9):982-8. · 2.16 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Morphometric and neuropsychological retrospective studies of amnestic mild cognitive impairment (MCI) have demonstrated that regional atrophies and cognitive impairments may differentiate stable from progressing MCI. No measure has proved helpful prospectively. In this study, twenty five amnestic MCI patients and 25 healthy controls underwent structural MRI and comprehensive neuropsychological assessment. The groups' grey matter volumes were compared with voxel based morphometry and were also correlated with scores obtained on paired associates learning and category fluency tasks. MCI patients had significantly reduced grey matter volume in left mediotemporal and other neocortical regions compared with controls. Atrophy in perirhinal and anterior inferior temporal cortex was associated with poor scores on both category fluency and paired associates learning tasks. After 36 months, 44% of the MCI sample converted to dementia. Converter and non-converter MCI subgroups differed in paired associates learning and in category fluency scores, and showed limited differences in grey matter loss in the hippocampal complex. Variable atrophy in the hippocampus was not a relevant element in the converter/non converter distinction, but converters had significant volumetric reductions in the perhirinal cortex and in other anterior temporal and frontal neocortical areas. A high proportion of converters (91%) could be identified from baseline data using a combination of measures of regional atrophy in left temporal association cortex and poor scores on paired associates learning and category fluency tasks. This combined approach may offer a better option than using each measure alone to prospectively identify individuals at more immediate risk of conversion to dementia in the MCI population. The clinical advantage of this combination of structural MRI and neuropsychological measures in predicting conversion to dementia will need additional prospective validation.
Current Alzheimer research 11/2011; 8(7):789-97. · 4.97 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: This study reports the case of a patient (AG) whose main calculation problem was with multiplication that was severely affected at all levels including that of conceptual knowledge. In contrast AG's problems with addition, subtraction and division were much less conspicuous and just involved the use of procedures. For all these latter operations, and for division in particular, conceptual knowledge was spared. Despite his procedural problems, AG in fact was fully aware that division consists of finding out how many times a given quantity is contained in another quantity. Thus while he was able to reach the correct results for division by subtracting the divisor from the dividend, he never used the reverse strategy to complete multiplication operations, i.e. add the number for as many times as the multiplier to complete the operation, and showed no awareness that this was what multiplying means, even when explicit suggestions were made by the examiner. The existence of AG's case could not be expected on the basis of theories holding that division depends on multiplication and that is not separately represented in semantic memory. It follows, therefore, that the extent to which division depends on multiplication needs to be reconsidered.