Effect of ageing on verbal and visuo-spatial working memory: Evidence from 880 individuals.

It is well-known that ageing is associated with a decrease in working memory abilities. It is not so clear at what age the decline begins and if there are differences in the decline of verbal and visuo-spatial working memory. This study investigates the effect of ageing on verbal and visuo-spatial working memory by comparing the performance of 880 subjects aged between 15- and 80-year old who were subdivided into five groups. The results show that age is negatively correlated with performance on both verbal and visuo-spatial working memory tasks. Specifically, we observed a gradual deterioration in performance with increasing age starting at 36-year old. Comparing the performance of the five groups, it is possible to observe a clear decline in both verbal and visuo-spatial working memory domains in subjects over 66-year old. However, in the next youngest age group, it is possible to notice differences in performance depending on the type of material being processed and the cognitive load required. This variability is discussed by analyzing the factors that may have influenced test performance.

Self-awareness rehabilitation after Traumatic Brain Injury: A pilot study to compare two group therapies.

BACKGROUND AND PURPOSE: Deficits of self-awareness (SA) are very common after severe acquired brain injury (sABI), especially in traumatic brain injury (TBI), playing an important role in the efficacy of the rehabilitation process. This pilot study provides information regarding two structured group therapies for disorders of SA. METHODS: Nine patients with severe TBI were consecutively recruited and randomly assigned to one SA group therapy programme, according either to the model proposed by Ben-Yishay & Lakin (1989) (B&L Group), or by Sohlberg & Mateer (1989) (S&M Group). Neuropsychological tests and self-awareness questionnaires were administered before and after a 10 weeks group therapy. RESULTS: Results showed that both SA and neuropsychological functioning significantly improved in both groups. CONCLUSION: It is important to investigate and treat self-awareness, also to improve the outcome of neuropsychological disorders. The two group therapies proposed seem to be specific for impulsivity and emotional dyscontrol and for cognitive disorders.

When a laser pen becomes a stick: remapping of space by tool-use observation in hemispatial neglect.

The role of active tool use in the remapping of space in hemispatial neglect patients has been extensively investigated. To date, however, there is no evidence that observing tool use can play a role in the remapping of space in hemispatial neglect patients. In this study, a patient with a severe hemispatial neglect in near but not far space and twelve healthy controls were asked to bisect near and far lines using a laser pen. The task was performed both before and immediately after sessions in which they merely observed the experimenter bisecting near and far lines with a stick. During the observation session, participants were either holding an identical stick or empty-handed. Results, in both the neglect patient and healthy controls, showed that observing the experimenter bisecting line while holding the same tool, produces a remapping of the far space into the near space. This result was particularly evident in the neglect patient where observing line-bisection task extended the spatial deficit from the near to the far space. Our results provide new empirical support to the idea that the space around us is not mapped in merely metrical terms, rather it seems to be deeply impacted by both action observation and execution.

The cognitive rehabilitation of limb apraxia in patients with stroke.

Apraxia is a higher level motor deficit that occurs when processing a goal-directed action. The apraxic deficit can manifest itself in absence of sensory input deficits or motor output deficits, neglect, frontal inertia or dementia. According to a clinical classification still largely in use, there are two main forms of limb apraxia: ideomotor (IMA) and ideational (IA), observed when a patient is required to imitate a gesture or use an object, respectively. In the present review, we examined only the cognitive treatments of both types of limb apraxia of a vascular aetiology. Despite the high prevalence of limb apraxia caused by left brain damage, and the fact that apraxia has been known for over a century, the literature regarding its rehabilitation is still very limited. This is partly due to the nature of the recovery from the deficit, and in part to the automatic-voluntary dissociation. Here we review those treatments that have proved most successful in helping patients to recover from limb apraxia.

Bodily self: an implicit knowledge of what is explicitly unknown.

We tested the hypothesis that the body self-advantage, i.e., the facilitation in discriminating self versus other people's body-effectors, is the expression of an implicit and body-specific knowledge, based mainly on the sensorimotor representation of one's own body-effectors. Alternatively, the body self-advantage could rely on visual recognition of pictorial cues. According to the first hypothesis, using gray-scale pictures of body-parts, the body self-advantage should emerge when self-body recognition is implicitly required and should be specific for body-effectors and not for inanimate-objects. In contrast, if the self-advantage is due to a mere visual-perceptual facilitation, it should be independent of the implicit or explicit request (and could be extended also to objects). To disentangle these hypotheses, healthy participants were implicitly or explicitly required to recognize either their own body-effectors or inanimate-objects. Participants were more accurate in the implicit task with self rather than with others' body-effectors. In contrast, the self-advantage was not found when an explicit recognition of one's own body-effectors was required, suggesting that the body self-advantage relies upon a sensorimotor, rather than a mere visual representation of one's own body. Moreover, the absence of both self/other and implicit/explicit effects, when processing inanimate-objects, underlines the differences between the body and other objects.

Selective impairment of self body-parts processing in right brain-damaged patients.

To investigate whether the processing of the visual appearance of one's own body, that is the corporeal self is a unified or modular function we submitted eight right brain-damaged (RBD) patients and a group of fourteen age-matched neurologically healthy subjects, to a visual matching-to-sample task testing for corporeal self processing. If corporeal self processing is a unique function (i.e., body- and face-parts are processed by the same network), patients impaired in self body-parts (i.e., showing no self-advantage) should be impaired also in self face-parts; alternatively, if corporeal self processing is a modular function (i.e., body- and face-parts are processed by different networks), patients impaired in self body-parts should be unimpaired in self face-parts, unless the face-module is also damaged by the lesion. Results showed that healthy participants were more accurate in processing pictures representing their own as compared to other people's body- and face-parts, showing the so-called self-advantage. The patients' findings revealed a simple dissociation, in that patients who were impaired in the processing of self-related body-parts showed a preserved self-advantage when processing self-related face-parts, thus providing initial evidence of a modular representation of the corporeal self.