Luigi Pugnetti

Evaluation and retraining of adults' cognitive impairments : which role for virtual reality technology ?

Immersive virtual reality (IVR) is a technology already developed to assist cognitive psychologists and therapists in their clinical work with brain-damaged patients. The rationale, the software and the hardware of the first application (ARCANA 1) based on affordable technology are discussed here, in order to provide a concrete example of what the authors think may be the role of IVR as a clinical tool. Although prospects are exciting, extensive research is needed to validate this new approach and reveal its limitations and advantages.

Probing Memory and Executive Functions with Virtual Reality: Past and Present Studies

The technology of virtual reality (VR) has been used to develop interactive programs that simulate everyday life environments, where healthy subjects and patients with central nervous system dysfunctions are asked to carry out tasks that probe incidental memory and executive functions. The results of three studies support previous claims that VR-based tests overcome several limitations of traditional paper-and-pencil tests, are at least as sensitive to target cognitive impairments, while providing a richer range of opportunities for measuring behavior. Preliminary analyses also suggest that results of VR-based memory tests are replicable across laboratories and subjects samples and that the technology is well-accepted and tolerated by both healthy and impaired subjects.

Lymphocyte subsets in schizophrenic disorders: relationship with clinical, neuromorphological and treatment variables

Peripheral blood lymphocyte subsets and serum immunoglobulin levels were assessed in 42 patients and 37 healthy controls. 24 patients were free from neuroleptic medication and 15 had never been treated with neuroleptics. 31 patients had a diagnosis of schizophrenia (DSM-III criteria) and 11 a diagnosis of a disorder of the schizophrenic spectrum. As compared to healthy subjects, the drug naive schizophrenic patient group showed an increase of T suppressor lymphocytes, while the drug-treated schizophrenic group showed an increase of T helper lymphocytes. The drug-treated schizophrenic group differed from the drug naive one relative to a decrease of T suppressor lymphocytes. As compared to healthy subjects, the drug naive spectrum disorder patients showed an increase of absolute number of lymphocytes, while the drug treated spectrum group showed an increase of B lymphocytes. These findings did not correlate with any clinical or neuromorphological variables taken into account.

Vestibular evoked myogenic potentials in multiple sclerosis: clinical and imaging correlations

Patients with multiple sclerosis (MS) frequently report symptoms related to vestibular disorders in the course of their disease. At present, the fundamental tests assessing vestibulospinal involvement are posturography and vestibular evoked myogenic potentials (VEMPs). While posturography cannot be performed in every subject requiring minimal stance control, VEMPs do not require any specific skill on the part of the subjects and they may be investigated in all patients able to sit. VEMPs were recorded for 40 patients (17 men, 23 women; mean age 38 years, range 17-71 years) fulfilling diagnostic criteria of clinically defined MS, by means of rarefaction clicks, recording modulation of sterno-cleido-mastoideus tonic contraction saccule-mediated modulation. VEMPs were found to be abnormal in 28 of 40 patients. In 18 of the cases the VEMPs were asymmetric, i.e., had a prolonged latency on one side. In six cases latency was increased on both sides (mean delay 4.1 ms). In four subjects VEMPs were absent on one side. C oncordance with clinical findings of presence/absence of brainstem involvement was found in 55% and with MRI findings in 65% of the cases. A bnormal VEMPs indicated brainstem dysfunction in four patients (10%) with normal MRI and no specific clinical signs.

The application of virtual reality to document coping deficits after a stroke: Report of a case

An immersive virtual reality (IVR) paradigm to assess cognitive flexibility and problem solving was used to document everyday life-coping failures in a patient with cognitive sequelae of an anterior left thalamic stroke. Three years after the ischemie event, the patient was showing clear signs of frontal lobe dysfunction when left unsupervised in real-life settings, yet his performance on traditional neuropsychological tests tapping frontal functions was unremarkable. We speculated, and provided evidence, that his conduct was influenced by the setting and the presence of an examiner who would strengthen his impaired ability to self-generate control over a number of higher order cognitive activities. Thanks to the immersive effect and nonverbal aspects of the interaction provided by IVR, we could document our patients cognitive difficulties on two separate occasions. The reasons why IVR was superior to traditional tests are analyzed with reference to well-known cognitive models of the way frontal networks...

Virtual Environments in the Diagnosis, Prevention, and Intervention of Age-Related Diseases: A Review of VR Scenarios Proposed in the EC VETERAN Project

A group of worldwide virtual reality and health-care researchers have decided to combine their efforts in a multidisciplinary project titled VETERAN-virtual environments in the diagnosis, prevention and intervention of age-related diseases. The main goal of the VETERAN project is the tuning and testing of different virtual environments, designed to address the cognitive/functional impairments that may occur due to the aging process and age-related disorders. In particular the developed modules will address the problems commonly found in the following pathologies that have a strong impact on the elderly health care policy: Alzheimers disease and other senile dementias; stroke and unilateral spatial neglect; mobility-related accidents within specific environments (e.g., falls, shocks). The project will focus on research into clinical aspects of age-related diseases and disorders of high morbidity and specifically target goals of prevention, treatment, or delay in onset. Another goal of the VETERAN project is to define and develop new protocols and tools to be used for general rehabilitation purposes. These tools will aim to provide systematic restorative training within the context of functionally relevant, ecologically valid simulated environments. This approach is hoped to optimise the degree of transfer of training and/or generalisation of learning to the persons real world environment.

Vertigo and multiple sclerosis: aspects of differential diagnosis

Abstract. Equilibrium disorders caused by involvement of brainstem and cerebellar structures are common in patients with multiple sclerosis (MS), but peripheral conditions such as benign paroxysmal positional vertigo (BPPV) can be sometimes confused with those of a central origin. Therefore, an accurate otoneurologic investigation paying attention to differential diagnosis aspects should be performed in these subjects. Among available diagnostic tools, electro-oculography, posturography and vestibular evoked myogenic potentials (VEMPs) are especially suited to assess vestibulo-oculomotor and vestibulospinal systems. This paper briefly describes the most recent otoneurologic diagnostic strategies for MS patients and the results of initial clinical experiences, and finally provides suggestions for differentiating MS-related vestibular disorders from other common otoneurological conditions.

Sleep disturbance and fatigue in mild relapsing remitting multiple sclerosis patients on chronic immunomodulant therapy: an actigraphic study

Background: poor sleep is common in MS and it contributes to fatigue. The β interferons produce systemic effects which may not adapt and may induce fatigue. Objective: to verify whether subjective poor sleep and fatigue during chronic therapy correspond to reduced sleep efficiency obtained by actigraphy at home. Methods: 42 ambulatory relapsing remitting MS patients with mild disability were monitored for at least 7 nights. Habitual sleep quality and fatigue were assessed with the MOS sleep measure and the Fatigue Severity Scale. Sleep logs provided daily sleep quality assessments during actigraphy at home. Patients were grouped according to their current treatment: no therapy, glatiramer acetate, IFNβ 3 times a week, and IFNβ once a week. Results and Conclusion: sleep efficiency was reduced by an average of 5% in 2/3 of the nights following IFNβ injections compared to the other nights, and daily sleep ratings correlated with actigraphy. Patients on glatiramer acetate also showed a lower sleep efficiency than patients without therapy. Actigraphy data were only modestly correlated with MOSsm scores, not with fatigue. Long term adaptation of sleep effects of immunomodulant agents is incomplete and needs to be considered in treatment planning and assessment of sleep in MS.

Bromocriptine therapy in chronic schizophrenia: Effects on symptomatology, sleep patterns, and prolactin response to stimulation

Ten chronic schizophrenic patients were given bromocriptine in doses increasing from 1.25 to 5 mg over 6 days (the low-dose therapy) and then up to 40 mg over 15 days (the high-dose therapy). Psychopathological status was assessed using the Brief Psychiatric Rating Scale, twice daily the first 6 days, and every 2 days thereafter. The prolactin (PRL) response to haloperidol stimulation (1 mg i.v.) was measured in five cases before and 3 days after the end of high-dose therapy, and in one patient before and 3 days after the end of low-dose therapy. Electroencephalographic sleep studies were carried out before therapy and every 2 nights during low-dose therapy in five patients, and in two cases during high-dose therapy. Bromocriptine therapy modified neither clinical symptomatology nor sleep patterns. The PRL response to haloperidol after therapy was markedly lower than that before therapy in the five patients treated with high doses, and markedly higher in the single patient tested who was treated only with low-dose therapy.

EEG Evidence of Posterior Cortical Disconnection in PD and Related Dementias

ABSTRACT Electroencephalogram (EEG) reactivity to eyes opening and 12-Hz photic stimulation was investigated in 14 healthy elderly subjects, 21 parkinsonian patients (PD), 7 demented parkinsonian patients (PDD), and 10 patients with Lewy body dementia (LBD) using global field synchronization (GFS). During eyes closed Theta GFS was increased in Parkinsons disease and patients and alpha1 GFS was decreased in LBD subjects. During 12-Hz intermittent photic stimulation (IPS), reactivity of posterior electrodes was decreased in PD and LBD patients. No reactivity was observed in PDD. Results are consistent with a graded posterior cortical disconnection in parkinsonian syndromes and with a model of dopamine-modulated thalamocortical interplay in visual processing.