442 research outputs found

    Further evidence of the contribution of the ear canal to directional hearing: design of a compensating filter

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    It has been proven, and it is well documented in literature, that the directional response in HRTFs comes largely from the effect of the pinnae. However, few studies have analysed the contribution given by the remaining part of the external ear, particularly the ear canal. This work investigates the directionally dependent response of the modelled ear canal of a dummy head, assuming that the behaviour of the external ear is sufficiently linear to be approximated by an LTI system. In order to extract the ear canal\u27s transfer function, two critical microphone placements (at the eardrum and at the beginning of the cavum conchae) have been used. The system has been evaluated in several positions, along the azimuth plane and at different degrees of elevation. The results point out a non-negligible directional dependence that is well within the normal hearing range; based on these findings, physical models of the ear canal have been analysed and evaluated. We have also considered the practical application to binaural listening, and the colouration originated by the superimposition of the contribution of two ear canals (the listener\u27s and the dummy head\u27s). A compensating FIR filter with arbitrary frequency response is discussed as a possible fix

    Using the Oxford cognitive screen to detect cognitive impairment in stroke patients. A comparison with the Mini-Mental State Examination

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    Background: The Oxford Cognitive Screen (OCS) was recently developed with the aim of describing the cognitive de cits after stroke. The scale consists of 10 tasks encom- passing ve cognitive domains: attention and executive function, language, memory, number processing, and praxis. OCS was devised to be inclusive and un-confounded by aphasia and neglect. As such, it may have a greater potential to be informative on stroke cognitive de cits of widely used instruments, such as the Mini-Mental State Examination (MMSE) or the Montreal Cognitive Assessment, which were originally devised for demented patients. Objective: The present study compared the OCS with the MMSE with regards to their ability to detect cognitive impairments post-stroke. We further aimed to examine perfor- mance on the OCS as a function of subtypes of cerebral infarction and clinical severity. Methods: 325 rst stroke patients were consecutively enrolled in the study over a 9-month period. The OCS and MMSE, as well as the Bamford classi cation and NIHSS, were given according to standard procedures. results: About a third of patients (35.3%) had a performance lower than the cutoff (<22) on the MMSE, whereas 91.6% were impaired in at least one OCS domain, indicating higher incidences of impairment for the OCS. More than 80% of patients showed an impairment in two or more cognitive domains of the OCS. Using the MMSE as a standard of clinical practice, the comparative sensitivity of OCS was 100%. Out of the 208 patients with normal MMSE performance 180 showed impaired performance in at least one domain of the OCS. The discrepancy between OCS and MMSE was particularly strong for patients with milder strokes. As for subtypes of cerebral infarction, fewer patients demonstrated widespread impairments in the OCS in the Posterior Circulation Infarcts category than in the other categories. conclusion: Overall, the results showed a much higher incidence of cognitive impairment with the OCS than with the MMSE and demonstrated no false negatives for OCS vs MMSE. It is concluded that OCS is a sensitive screen tool for cognitive de cits after stroke. In particular, the OCS detects high incidences of stroke-specific cognitive impairments, not detected by the MMSE, demonstrating the importance of cognitive pro ling.Background: The Oxford Cognitive Screen (OCS) was recently developed with the aim of describing the cognitive deficits after stroke. The scale consists of 10 tasks encompassing five cognitive domains: attention and executive function, language, memory, number processing, and praxis. OCS was devised to be inclusive and un-confounded by aphasia and neglect. As such, it may have a greater potential to be informative on stroke cognitive deficits of widely used instruments, such as the Mini-Mental State Examination (MMSE) or the Montreal Cognitive Assessment, which were originally devised for demented patients. Objective: The present study compared the OCS with the MMSE with regards to their ability to detect cognitive impairments post-stroke. We further aimed to examine performance on the OCS as a function of subtypes of cerebral infarction and clinical severity. Methods: 325 first stroke patients were consecutively enrolled in the study over a 9-month period. The OCS and MMSE, as well as the Bamford classification and NIHSS, were given according to standard procedures. Results: About a third of patients (35.3%) had a performance lower than the cutoff(< 22) on the MMSE, whereas 91.6% were impaired in at least one OCS domain, indicating higher incidences of impairment for the OCS. More than 80% of patients showed an impairment in two or more cognitive domains of the OCS. Using the MMSE as a standard of clinical practice, the comparative sensitivity of OCS was 100%. Out of the 208 patients with normal MMSE performance 180 showed impaired performance in at least one domain of the OCS. The discrepancy between OCS and MMSE was particularly strong for patients with milder strokes. As for subtypes of cerebral infarction, fewer patients demonstrated widespread impairments in the OCS in the Posterior Circulation Infarcts category than in the other categories. Conclusion: Overall, the results showed a much higher incidence of cognitive impairment with the OCS than with the MMSE and demonstrated no false negatives for OCS vs MMSE. It is concluded that OCS is a sensitive screen tool for cognitive deficits after stroke. In particular, the OCS detects high incidences of stroke-specific cognitive impairments, not detected by the MMSE, demonstrating the importance of cognitive profiling. © 2018 Mancuso, Demeyere, Abbruzzese, Damora, Varalta, Pirrotta, Antonucci, Matano, Caputo, Caruso, Pontiggia, Coccia, Ciancarelli, Zoccolotti and The Italian OCS Grou

    VARIABILITY OF DEPOSITIONAL SETTING ALONG THE NORTH-WESTERN SICILY CONTINENTAL SHELF (ITALY) DURING LATE QUATERNARY: EFFECTS OF SEA LEVEL CHANGES AND TECTONIC EVOLUTION

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    The geological, geomorphological and sedimentological features of the north-western Sicily continental shelf are here illustrated with the aim to propose a geological model able to explain the Neogene-Quaternary evolution of the Sicilian continental margin in the context of the central Mediterranean region. Above the continental shelf and upper slope the sedimentary succession, showing along the different sectors of the margin considerably variable internal geometry and stratigraphic relationships with the underlying units, is interpreted as a IV order depositional sequence (Late Quaternary Depositional Sequence, LQDS) deposited during the last eustatic change (last 125 ky). The lower boundary of the LQDS is represented by a subaerial erosional surface formed during the last eustatic sea level fall ended in the LGM (20-18 ka). This unconformity lies above a seaward dipping Pleistocene succession whose depositional architecture is in turn controlled by Quaternary eustatic sea-level fluctuations. A dense dataset of morphobathymetric and high resolution seismic data allowed to recognize along the continental shelf to bathyal plain system different types of continental shelf with different stratigraphic and morphostructural settings, associated to both large-scale processes and specific factors related to more local control: a) predominantly rocky shelves, both accompanied by a moderate frontal sedimentary prism and with a structural edge, in the structural highs of the Monti di Palermo offshore and around the main rocky headlands (Capo San Vito, Monte Catalfano); b), depositional shelves, in the Castellammare, Palermo and Termini Imerese gulfs, both with a regular seaward deepening of the substrate and with a substrate uplift at the shelf break. We confirm that depositional sequences in this margin are the result of the interaction between sea level changes and sedimentation, but demonstrate that the tectonic activity has played a key role, not only in the creation of different types of continental shelves, but also to determine the different characters of each sequence in different areas. The general tectonic uplift during the Pleistocene, together with the episodic alternation of extensional and compressional events, often with strike-slip component, is responsible for the thickness and facies variation both onland, where residual Pleistocene marine deposits today outcrops, and in the continental shelf, where most of the depositional sequences developed and are now recognized. As well tectonic activity exerted a control on the geomorphological features (e.g. pockmarks and mounds) of the present day coastal areas and shelf-slope system, as well as for the submarine canyons and the mass failure processes

    Prevalence and time course of post-stroke pain: A multicenter prospective hospital-based study

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    OBJECTIVE: Pain prevalence data for patients at various stages after stroke. DESIGN: Repeated cross-sectional, observational epidemiological study. SETTING: Hospital-based multicenter study. SUBJECTS: Four hundred forty-three prospectively enrolled stroke survivors. METHODS: All patients underwent bedside clinical examination. The different types of post-stroke pain (central post-stroke pain, musculoskeletal pains, shoulder pain, spasticity-related pain, and headache) were diagnosed with widely accepted criteria during the acute, subacute, and chronic stroke stages. Differences among the three stages were analyzed with χ(2)-tests. RESULTS: The mean overall prevalence of pain was 29.56% (14.06% in the acute, 42.73% in the subacute, and 31.90% in the chronic post-stroke stage). Time course differed significantly according to the various pain types (P < 0.001). The prevalence of musculoskeletal and shoulder pain was higher in the subacute and chronic than in the acute stages after stroke; the prevalence of spasticity-related pain peaked in the chronic stage. Conversely, headache manifested in the acute post-stroke stage. The prevalence of central post-stroke pain was higher in the subacute and chronic than in the acute post-stroke stage. Fewer than 25% of the patients with central post-stroke pain received drug treatment. CONCLUSIONS: Pain after stroke is more frequent in the subacute and chronic phase than in the acute phase, but it is still largely undertreated

    Transcranial random noise stimulation does not improve behavioral and neurophysiological measures in patients with subacute Vegetative-Unresponsive Wakefulness State (VS-UWS)

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    Background: The absence of efficient treatments capable to promote central nervous system recovery in patients in vegetative state (VS) due to a severe acquired brain injury highlights the need of exploring alternative neuromodulatory treatments that can lead to neurobehavioral gains. Some encouraging preliminary observations suggest that transcranial direct current stimulation could be effective in disorders of consciousness (DoC) patients, especially when applied on the dorsolateral prefrontal cortex (DLPFC) in patients with minimally conscious state (MCS) but not in those with VS. Objective: The primary aim of the present study was to verify if the application of transcranial random noise stimulation (tRNS) on the DLPFC might favor improvements of consciousness recovery in subacute VS-UWS. Methods: Nine patients with DoC due to traumatic brain injury (n D 1), anoxia (n D 3), and vascular damage (n D 5), have undergone a randomized, double-blind, shamcontrolled, neuromodulatory trial with tRNS of bilateral DLPFC. All patients were in a post-acute phase and the DoC onset ranged from 30 days to 4 months. The diagnosis of DoC was based on internationally established criteria from the Multi-Society Task Force on PVS, and classified as VS or MCS using the JFK Coma Recovery Scale- Revised scores (CRS-R). We used CRS-R, Synek Scale, Ad-Hoc semi-quantitative scale and the Clinical Global Impression-Improvement scale to measure behavioral and electrophysiological changes during tRNS intervention. All patients were also treated with daily conventional rehabilitation treatment. Results: No significant differences emerged between active and sham groups regarding improvements of level of consciousness, as well as on electroencephalographic data. Only one patient showed emergence from VS-UWS, evolving from VS to MCS after the tRNS stimulation, at a distance of 3 weeks from the enrolment into the study. Conclusion: Repeated applications of tRNS of the DLPFC, even if applied in a subacute phase of VS-UWS state, did not modify behavioral and neurophysiological outcomes differently than sham stimulation

    The impact of cognitive function deficits and their recovery on functional outcome in subjects affected by ischemic subacute stroke: results from the Italian multicenter longitudinal study CogniReMo

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    Background: The recovery of independence in activities of daily living is a fundamental goal of rehabilitation programs in subjects affected by subacute stroke. Rehabilitation is focused both on motor and cognitive aspects, and some evidence has reported cognitive deficits as prognostic factors of motor recovery. However, rehabilitation is a dynamic process during which executive functions and motor functions should be improved. Aim: The aim of the study is to evaluate the relationships between impairments in cognitive functions and recovery of functional independence in stroke patients during the subacute phase. Design: Multicenter observational study. Setting: Intensive rehabilitation units. Population: A sample of 319 stroke patients in subacute phase (70.6±11.6 years, 40.4% females), consecutively admitted from November 2019 to July 2021 at sixteen rehabilitation centers were enrolled in this observational, prospective and multicentric study with longitudinal assessments. Methods: Cognitive and functional assessments were performed at hospital admission and discharge, including Oxford Cognitive Screen, modified Barthel Index, Functional Independent Measure, Fugl-Meyer assessment scale and National Institutes of Health Stroke Scale. Results: A regression analysis identified five predictors (out of about 200 tested variables) of functional recovery related to four aspects assessed at admission: functional status (P&lt;0.001), lower limb functioning (P=0.002), attention (P=0.011), and executive functions (P=0.017). Furthermore, patients who recovered deficits in executive functions had the same recovery of those without deficits, whereas those who maintained deficits had a smaller recovery (P=0.019). Conclusions: The relationship between cognitive and motor deficits is increasingly highlighted and the recovery of executive functions deficits seems to contribute to motor recovery. Clinical rehabilitation impact: Our results suggest that the recovery of executive functions may promote the recovery of the functional outcome of the patient with subacute stroke. Future treatment protocols may benefit from paying more attention to the recovery of executive functions

    Italian standardization of the Apples Cancellation Test

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    Hemispatial neglect due to right parieto-temporo-frontal lesions has a negative impact on the success of rehabilitation, resulting in poor functional gain. Recent research has shown that different types of neglect can impact in a different way on rehabilitation outcomes. The availability of a sensitive test, useful for distinguishing egocentric and allocentric forms of neglect, may be clinically important as all current clinical instruments fail to distinguish between these forms of disturbance, yet they differentially predict outcome. The Apples Test is a new instrument useful to evaluate both egocentric and allocentric forms of neglect. In order to establish Italian norms for this diagnostic instrument the test was administered to a sample of 412 healthy people of both genders (201 M and 211 F), aged from 20 to 80 years enrolled from 14 different rehabilitation centers in Italy. Based on the data, we established pathological performance cut-offs for the accuracy score (total omission errors), the asymmetry score for egocentric neglect (omission error difference), the asymmetry score for allocentric neglect (commission error difference) and execution time. The usefulness of the Apples Test for diagnostic purposes is illustrated by presenting three patients with different forms of neglect (egocentric, allocentric and mixed neglect)

    'Less is more': validation with Rasch analysis of five short-forms for the Brain Injury Rehabilitation Trust Personality Questionnaires (BIRT-PQs).

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    Background: Previous analyses demonstrated a lack of unidimensionality, item redundancy, and substantial administrative burden for the Brain Injury Rehabilitation Trust Personality Questionnaires (BIRT-PQs). Objective: To use Rasch Analysis to calibrate five short-forms of the BIRT-PQs, satisfying the Rasch model requirements. Methods: BIRT-PQs data from 154 patients with severe Acquired Brain Injury (s-ABI) and their caregivers (total sample = 308) underwent Rasch analysis to examine their internal construct validity and reliability according to the Rasch model. Results: The base Rasch analyses did not show sufficient internal construct validity according to the Rasch model for all five BIRT-PQs. After rescoring 18 items, and deleting 75 of 150 items, adequate internal construct validity was achieved for all five BIRT-PQs short forms (model chi-square p-values ranging from 0.0053 to 0.6675), with reliability values compatible with individual measurements. Conclusions: After extensive modifications, including a 48% reduction of the item load, we obtained five short forms of the BIRT-PQs satisfying the strict measurement requirements of the Rasch model. The ordinal-to-interval measurement conversion tables allow measuring on the same metric the perception of the neurobehavioral disability for both patients with s-ABI and their caregivers
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