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Several studies have shown that impairments in a sensory modality can induce perceptual deficits in tasks involving the remaining senses. For example, people with retinal degenerative diseases like Macular Degeneration (MD) and with central scotoma show biased auditory localization abilities towards the visual field's scotoma area. This result indicates an auditory spatial reorganization of cross-modal processing in people with scotoma when the visual information is impaired. Recent works showed that multisensory training could be beneficial to improve spatial perception. In line with this idea, here we hypothesize that audio-visual and motor training could improve people's spatial skills with retinal degenerative diseases. In the present study, we tested this hypothesis by testing two groups of scotoma patients in an auditory and visual localization task before and after a training or rest performance. The training group was tested before and after multisensory training, while the control group performed the two tasks twice after 10 min of break. The training was done with a portable device positioned on the finger, providing spatially and temporally congruent audio and visual feedback during arm movement. Our findings show improved audio and visual localization for the training group and not for the control group. These results suggest that integrating multiple spatial sensory cues can improve the spatial perception of scotoma patients. This finding ignites further research and applications for people with central scotoma for whom rehabilitation is classically focused on training visual modality only.

Behavioral and neuropsychological studies suggest that real actions and pantomimed actions tap, at least in part, different neural systems. Inspired by studies showing weight-attunement in real grasps, here we asked whether (and to what extent) kinematics of pantomimed reach-to-grasp movement can reveal the weight of the pretended target. To address this question, we instructed participants (n = 15) either to grasp or pretend to grasp toward two differently weighted objects, i.e., a light object and heavy object. Using linear discriminant analysis, we then proceeded to classify the weight of the target - either real or pretended - on the basis of the recorded movement patterns. Classification analysis revealed that pantomimed reach-to-grasp movements retained information about object weight, although to a lesser extent than real grasp movements. These results are discussed in relation to the mechanisms underlying the control of real and pantomimed grasping movements.

The aims of this study were: to evaluate a homogeneous sample of truck drivers of dangerous goods (TDDGs) in order to assess the prevalence of obstructive sleep apnea (OSA), and to verify the secondary risk of motor vehicle accidents (MVAs) and near miss accidents (NMAs) in this population. A sample of 283 male TDDGs was evaluated. None of the subjects reported OSA symptoms before screening. Clinical and physical evaluation, Epworth Sleepiness Scale (ESS), and the items on OSA from the Sleep Disorder Score (SDS) questionnaire were used to select subjects with suspicion of OSA. Polysomnography (PSG) was performed to confirm the diagnosis of OSA. The frequency of MVAs and NMAs was assessed at baseline for the whole sample, and also for the drivers with severe OSA after two years of continuous positive airway pressure (CPAP) treatment. The mean age of the sample was 42.3 ± 8.3 years. A total of 139 (49.1%) subjects had suspected OSA, and the PSG study confirmed the diagnosis in 35.7%. A significant association between OSA severity and NMAs was observed, and subjects with severe OSA showed a near five-fold increased risk of NMAs (OR = 4.745, 95% CI 1.292-17.424, p = 0.019). After two years of CPAP treatment, the rate of NMAs was comparable with drivers without OSA, showing the efficacy of therapy. This study showed an unexpected high prevalence of OSA in TDDGs. Untreated subjects with severe OSA had a significantly increased risk of NMAs. In professional drivers, screening, treatment, and management of OSA are mandatory for reducing road accident risk and improving road safety.

Objectives To investigate cerebral correlates of action execution with affected and non-affected hand in children with hemiplegic Cerebral Palsy (CP). Methods We acquired electroencephalographic signal (EEG) of 9 CP children (5 F, 4 M, mean age 8Y, SD 2Y) and of 10 control healthy children (CC) (4 F, 6 M, mean age 10 Y, SD 2Y). For comparison with healthy subjects, we considered CP affected hand as non-dominant and the unaffected hand as dominant. All subjects performed a reaching and grasping movement with both hands. As a neurophysiological measure we considered event related desynchronization (ERD) in the mu frequency band (8–13 Hz) which is a neural correlate of motor processes (Pfurtscheller 1997). For all considered measures, we evaluated the GROUP and MOVED HAND effects using post hoc ANOVA. Results Both groups showed a clear mu desynchronization to action execution of both hands. A stronger mu ERD, in both dominant and not-dominant hand, was found in healthy controls compared to CP. Conclusions The motor cortex contralateral to unaffected hand showed a reduced mu ERD, confirming that even in hemiplegic CP children, cortical damage extends to both hemispheres and can be inferred by mu ERD. Moreover, clinical and functional scores, and mu desynchronization are jointly and coherently affected by CP.

Subtle cognitive impairment can be detected in early Parkinson's disease (PD). In a consecutive series of de novo, drug-naive PD patients, we applied stepwise regression analysis to assess which clinical, neuropsychological, and functional neuroimaging (dopamine transporter [DAT] and perfusion single photon emission computed tomography [SPECT]) characteristics at baseline was predictive of cognitive decline during an average follow-up time of about 4 years. Decline both in executive (R(2) = 0.54; p = 0.0001) and visuospatial (R(2) = 0.56; p = 0.0001) functions was predicted by the couple of Unified Parkinson's Disease Rating Scale (UPDRS)-III score and caudate dopamine transporter (DAT) uptake in the less affected hemisphere (LAH). Verbal memory and language decline was predicted instead by caudate DAT uptake and brain perfusion in a posterior parieto-temporal area of the less affected hemisphere (R(2) = 0.42; p = 0.0005). No significant effect was shown for age, baseline ...

This paper presents a multimodal interactive system for non-visual (auditory-haptic) exploration of virtual maps. The system is able to display haptically the height profile of a map, through a tactile mouse. Moreover, spatial auditory information is provided in the form of virtual anchor sounds located in specific points of the map, and delivered through headphones using customized Head-Related Transfer Functions (HRTFs). The validity of the proposed approach is investigated through two experiments on non-visual exploration of virtual maps. The first experiment has a preliminary nature and is aimed at assessing the effectiveness and the complementarity of auditory and haptic information in a goal reaching task. The second experiment investigates the potential of the system in providing subjects with spatial knowledge: specifically in helping with the construction of a cognitive map depicting simple geometrical objects. Results from both experiments show that the proposed concept, design, and implementation allow to effectively exploit the complementary natures of the " proximal " haptic modality and the " distal " auditory modality. Implications for orientation & mobility (O&M) protocols for visually impaired subjects are discussed.

This paper presents a multimodal interactive system for non-visual (auditory-haptic) exploration of virtual maps. The system is able to display haptically the height profile of a map, through a tactile mouse. Moreover, spatial auditory information is provided in the form of virtual anchor sounds located in specific points of the map, and delivered through headphones using customized Head-Related Transfer Functions (HRTFs). The validity of the proposed approach is investigated through two experiments on non-visual exploration of virtual maps. The first experiment has a preliminary nature and is aimed at assessing the effectiveness and the complementarity of auditory and haptic information in a goal reaching task. The second experiment investigates the potential of the system in providing subjects with spatial knowledge: specifically in helping with the construction of a cognitive map depicting simple geometrical objects. Results from both experiments show that the proposed concept, design, and implementation allow to effectively exploit the complementary natures of the " proximal " haptic modality and the " distal " auditory modality. Implications for orientation & mobility (O&M) protocols for visually impaired subjects are discussed.

Cognitive impairment in Parkinson's disease (PD) and atypical parkinsonian syndromes is gaining increased clinical significance. The neurochemical and neuropathological basis in the various parkinsonian forms and even in an individual patient are not fully elucidated yet and could be heterogeneous. Loss of dopaminergic, cholinergic and noradrenergic innervation has been suggested to be the underlying neurochemical deficits for cognitive impairment and dementia in PD, but the onset of cognitive impairment and the progression to dementia may not share the same underlying neurochemical basis. Similarly, pathological evidence is also heterogeneous, ranging from subcortical pathology, limbic or cortical Lewy body type degeneration, and Alzheimer's type pathology that can be found even in the same patient with PD dementia (PDD). Typically, the prototype of early cognitive deficit in PD is a dysexecutive syndrome, but other cognitive domains are more involved when dementia develops...

ABSTRACT Mathematical models of sleep EEG-power in different frequency bands and their dynamics in physiological human sleep offer a conceptual framework for the analysis of the macrostructure of sleep and for the interpretation of sleep regulatory processes. We present a mathematical model of sleep-EEG structure obtained by combining the elaborated version of the two-process model of sleep regulation, which includes the ultradian dynamics of Slow Wave Activity (SWA) and the reciprocal interaction model of REM regulation suggested by McCarley and Hobson. The model parameters are estimated by an optimisation procedure which performs a best fit algorithm to empirical data collected from the polysomnographic recordings, obtaining in such way a data set of parameters from each case. We apply the model to the analysis of patterns in some sleep disorders, such identifying parameters characterizing pathological sleep in comparison to controls. An important result is obtained in the study of Narcolepsy: the variation in parameter values describing the strength of RemOn /RemOff interaction is the major feature characterizing the sleep, it can explain sleep onset REM periods (SOREMPs) and variations in the length of REM-NREM sleep cycles. Other pathologies are object of work in progress, the aim is the analysis of those cyclic patterns responsible of the progressive destructuring of sleep in terms of the variability of parameters values, being these ones ascribable to the neurophysiological structures involved in the pathological context. Our work stresses the importance of mathematical modelling in understanding the processes regulating the sleep structure, also supporting the detection of the structures characterising pathology.

A subtle cognitive impairment can be detected early in the course of Parkinson's disease (PD). Executive, memory and visuospatial functions are specifically affected, but the underlying pathophysiological basis is not well elucidated yet and may be heterogeneous. The recent identification of a PD-related cognitive metabolic pattern (PDCP), including hypometabolism in associative frontal, parietal and posterior limbic structures, has integrated the classical notion of a striato-frontal syndrome at the basis of cognitive dys-function. Recent evidence suggests that whilst executive dys-function is seen in virtually all PD patients, visuospatial and memory impairment may share a higher risk for the subsequent development of dementia. By means of perfusion SPECT and [18F]FDG-PET, cortical dys-function may be highlighted since the early stages, it is more evident in PD patients with Mild Cognitive Impairment (MCI), and reaches the maximum in PD dementia (PDD). Posterior temporo-parieto-occipital dys-function in associative and limbic cortex, closely resembling that found in Alzheimer's disease patients, is found in PDD, with a more severe occipital hypometabolism and a relatively milder hypometabolism in medial temporal lobe structures. Furthermore, deficit of acetylcholinesterase (AchE) can be found by means of [11C]MP4A-PET already in early stage of PD, especially in posterior regions, then becoming more severe in PDD and in dementia with Lewy bodies (DLB). Administration of AchE inhibitors to PDD patients increased brain metabolism in bilateral frontal and left parietal regions, and left posterior cingulate. Finally, the recent availability of radiopharmaceuticals able to disclose amyloid brain deposition has allowed to demonstrate amyloid load in a part of patients with PDD, possibly due to diffuse rather than neuritic plaques. Brain PET and SPECT have strongly contributed to the understanding of the pathophysiology of cognitive impairment in PD and may serve as probes to monitor the effects of therapeutic interventions.