Anna Cantagallo

Encoding of human action in Broca's area.

Brocas area has been considered, for over a century, as the brain centre responsible for speech production. Modern neuroimaging and neuropsychological evidence have suggested a wider functional role is played by this area. In addition to the evidence that it is involved in syntactical analysis, mathematical calculation and music processing, it has recently been shown that Brocas area may play some role in language comprehension and, more generally, in understanding actions of other individuals. As shown by functional magnetic resonance imaging, Brocas area is one of the cortical areas activated by hand/mouth action observation and it has been proposed that it may form a crucial node of a human mirror-neuron system. If, on the one hand, neuroimaging studies use a correlational approach which cannot offer a final proof for such claims, available neuropsychological data fail to offer a conclusive demonstration for two main reasons: (i) they use tasks taxing both language and action systems; and (ii) they rarely consider the possibility that Brocas aphasics may also be affected by some form of apraxia. We administered a novel action comprehension test--with almost no linguistic requirements--on selected frontal aphasic patients lacking apraxic symptoms. Patients, as well as matched controls, were shown short movies of human actions or of physical events. Their task consisted of ordering, in a temporal sequence, four pictures taken from each movie and randomly presented on the computer screen. Patients performance showed a specific dissociation in their ability to re-order pictures of human actions (impaired) with respect to physical events (spared). Our study provides a demonstration that frontal aphasics, not affected by apraxia, are specifically impaired in their capability to correctly encode observed human actions.

Development of neuropsychiatric symptoms in poststroke patients: a cross-sectional study.

Objective:  The study aimed to characterize neuropsychiatric symptomatology and its evolution in a large group of poststroke patients during their first year.

Imagery mnemonics for the rehabilitation of memory: A randomised group controlled trial

Apart from a few, encouraging, single-case studies, evidence of imagery-based mnemonics for the rehabilitation of memory in brain-damaged individuals is sparse. The literature suggests that if imagery is of any use, then it should be applied to mildly memory impaired patients, the learning process should be tailored and a direct transfer training to individual memory problems should be implemented into the training. We compared the outcome of such a programme (nine memory impaired patients) with other approaches to the rehabilitation of memory used in participating centres (12 memory impaired patients). After 4 weeks of baseline and a repeated test battery patients received 30 single sessions of therapy in 10 weeks. Results suggest that imagery training significantly improves delayed recall of everyday relevant verbal materials (stories, appointments). Frequency of memory problems observed by relatives is reduced and each of these effects is stable at 3-month follow-up. This study suggests that a simple imagery technique can improve relevant aspects of everyday verbal memory performance.

Neuropsychiatric Disorders in Persons With Severe Traumatic Brain Injury: Prevalence, Phenomenology, and Relationship With Demographic Clinical and Functional Features

Objective:To characterize neuropsychiatric symptoms in a large group of individuals with severe traumatic brain injury (TBI) and to correlate these symptoms with demographic, clinical, and functional features. Methods:The Neuropsychiatric Inventory (NPI), a frequently used scale to assess behavioral, emotional, and motivational disorders in persons with neurological diseases, was administered to a sample of 120 persons with severe TBI. Controls were 77 healthy subjects. Results:A wide range of neuropsychiatric symptoms was found in the population with severe TBI: apathy (42%), irritability (37%), dysphoria/depressed mood (29%), disinhibition (28%), eating disturbances (27%), and agitation (24%). A clear relationship was also found with other demographic and clinical variables. Conclusion:Neuropsychiatric disorders constitute an important part of the comorbidity in populations with severe TBI. Our study emphasizes the importance of integrating an overall assessment of cognitive disturbances with a specific neuropsychiatric evaluation to improve clinical understanding and treatment of persons with TBI.

PRESERVED INSIGHT IN AN ARTIST WITH EXTRAPERSONAL SPATIAL NEGLECT

Several reports of cases of experienced artists showing neglect after a brain lesion can be gleaned from the literature. The analysis of their drawings might provide better insight into the symptoms of neglect than that of non-artistss production. However, most of these reports are anedoctal. We describe in some detail the case of neglect of a distinguished artist, the internationally known Federico Fellini (FF), whom we followed-up for two months after his right parietal stroke. The neuropsychological profile of his neglect syndrome was characterized by left visuo-motor neglect which persisted for two months. At onset, FF also showed indications of neglect dyslexia as well as some evidence of implicit processing of the neglected parts of visual stimuli. However, there was no sign of personal and representational neglect, and FF was well aware of his motor and attentional deficits. FFs neglect was characterised by several dissociations, of which the lack of functional carryover despite intact conceptual and semantic insight is the most relevant.

‘Moving’ a paralysed hand: bimanual coupling effect in patients with anosognosia for hemiplegia

Selective neurological impairments can shed light on different aspects of motor cognition. Brain-damaged patients with anosognosia for hemiplegia deny their motor deficit and believe they can still move the paralysed limb. Here we study, for the first time, if the anomalous subjective experience that their affected hand can still move, may have objective consequences that constrain movement execution with the opposite, intact hand. Using a bimanual motor task, in which anosognosic patients were asked to simultaneously trace out lines with their unaffected hand and circles with their paralysed hand, we found that the trajectories of the intact hand were influenced by the requested movement of the paralysed hand, with the intact hand tending to assume an oval trajectory (bimanual coupling effect). This effect was comparable to that of a group of healthy subjects who actually moved both hands. By contrast, brain-damaged patients with motor neglect or actual hemiplegia but no anosognosia did not show this bimanual constraint. We suggest that anosognosic patients may have intact motor intentionality and planning for the plegic hand. Rather than being merely an inexplicable confabulation, anosognosia for the plegic hand can produce objective constraints on what the intact hand does.

Narrative discourse in anomic aphasia

Anomic aphasia is a disturbance affecting lexical retrieval. Nonetheless, persons with this disorder may also experience difficulties in the construction of coherent narratives. Whether this symptom is a sign of a macrolinguistic difficulty per se or reflects the lexical disorder is still an open debate. In order to analyze the effect of the lexical impairment on macrolinguistic processing, we compared the narrative skills of a group of ten participants with chronic anomic aphasia with those of ten healthy control individuals matched for age and educational level. The anomic participants produced narratives with lowered speech rate, reduced mean length of utterance, fewer grammatically well-formed sentences, more semantic paraphasias. The macrolinguistic analysis showed that they also produced more errors of cohesion and global coherence and fewer lexical information units. Interestingly, their levels of thematic selection were normal. A bivariate correlational analysis showed a strong correlation between the production of errors of cohesion and production of complete sentences, and between production of errors of global coherence and lexical information units. These correlations showed that aspects related to lexical retrieval may affect macrolinguistic processing during the construction of a narrative. Indeed, it is suggested that lexical deficits lead to two main consequences: First, patients with anomia frequently interrupt the utterances they are producing and this reduces the levels of sentence completeness and the overall degree of cohesion across the utterances; Second, they use strategies to cope with the lexical impairment and produce a quantity of lexical fillers and repetitions that, clustered in utterances, reduce the levels of global coherence.

Patterns of attentional impairment following closed head injury: a collaborative European study.

A comprehensive assessment of both selective (focused attention, divided attention) and intensive (alertness and vigilance) attentional processes was performed on 106 patients with closed head injury using a computerised battery for the evaluation of attention. All patients were tested at least five months after their accident. A high percentage of patients were pathological in tests mapping the selective components of attention while only a minority were impaired on tests mapping the intensive components of attention. Three different subgroups of patients with consistent performance patterns were evidenced. The psychometric characteristics of the battery and its possible clinical usefulness are discussed.

Neuropsychological evidence for separating components of visuo–spatial working memory

There is increasing evidence to support the idea that visuo–spatial working memory can be segregated into separate cognitive subsystems. However, the nature of these systems remains unclear. In this paper we report data from two brain injured patients suggesting that information about visual appearance is retained in a different subsystem from information about spatial location, and that this differential processing can be observed when the style of presentation (sequential or simultaneous) is controlled.

Theory of Mind in patients with ventromedial or dorsolateral prefrontal lesions following traumatic brain injury

Primary objective: Previous studies on patients with traumatic brain injuries (TBI) and diffuse brain damages have reported selective deficits in mental states reasoning or ‘Theory of Mind’ (ToM). The goal of the current study is to investigate the fundamental role of the prefrontal cortex in two ToM components: inferential reasoning and social perception. Research design: Selective cognitive impairments following a TBI provide crucial evidence for assessing competing models of specific aspects of the cognitive system. Method and procedure: This study compared the performance of patients with predominantly focal lesions in the ventromedial (n = 11) or dorsolateral prefrontal cortex (n = 7) with matched controls (n = 20). All subjects performed two ToM tasks: the Eyes Test and the Faux-pas Test. Results: It was found that both groups of patients performed equally poorly on the Eyes Test, but only patients with predominantly lesions in the ventromedial cortex performed poorly on the Faux-pas test. The group effects on ToM tasks could not be reduced to differences in the global severity of brain injuries. Conclusions: These results provide evidence supporting some current models of the fractionation of the mindreading system and support the claim that the ventromedial cortex plays a fundamental role in inferential reasoning.