The homology of hemispheric cortical areas plays a crucial role in brain functionality. Here, we extend this concept to the homology of the dominant and non-dominant hemi-bodies, investigating the ...relationship of the two corticospinal tracts (CSTs). The evoked responses provide an estimate of the number of in-phase recruitments via their amplitude as a suitable indicator of the neuronal projections' integrity. An innovative concept derived from experience in the somatosensory system is that their morphology reflects the recruitment pattern of the whole circuit.
CST homology was assessed via the Fréchet distance between the morphologies of motor-evoked potentials (MEPs) using a transcranial magnetic stimulation (TMS) in the homologous left- and right-hand first dorsal interosseous muscles of 40 healthy volunteers (HVs). We tested the working hypothesis that the inter-side Fréchet distance was higher than the two intra-side distances.
In addition to a clear confirmation of the working hypothesis (
< 0.0001 for both hemi-bodies) verified in all single subjects, we observed that the intra-side Fréchet distance was higher for the dominant than the non-dominant one. Interhemispheric morphology similarity increased with right-handedness prevalence (
= 0.004).
The newly introduced measure of circuit recruitment patterning represents a potential benchmark for the evaluation of inter-lateral mechanisms expressing the relationship between homologous hemilateral structures subtending learning and suggests that variability in recruitment patterning physiologically increases in circuits expressing greater functionality.
Health, as defined by the WHO, is a multidimensional concept that includes different aspects. Interest in the health conditions of the oldest-old has increased as a consequence of the phenomenon of ...population aging. This study investigates whether (1) it is possible to identify health profiles among the oldest-old, taking into account physical, emotional and psychological information about health, and (2) there are demographic and socioeconomic differences among the health profiles.
Latent Class Analysis with covariates was applied to the Mugello Study data to identify health profiles among the 504 nonagenarians residing in the Mugello district (Tuscany, Italy) and to evaluate the association between socioeconomic characteristics and the health profiles resulting from the analysis.
This study highlights four groups labeled according to the posterior probability of determining a certain health characteristic: "healthy", "physically healthy with cognitive impairment", "unhealthy", and "severely unhealthy". Some demographic and socioeconomic characteristics were found to be associated with the final groups: older nonagenarians are more likely to be in worse health conditions; men are in general healthier than women; more educated individuals are less likely to be in extremely poor health conditions, while the lowest-educated are more likely to be cognitively impaired; and office or intellectual workers are less likely to be in poor health conditions than are farmers.
Considering multiple dimensions of health to determine health profiles among the oldest-old could help to better evaluate their care needs according to their health status.
Abstract Background A globally harmonized protocol (HarP) for manual hippocampal segmentation based on magnetic resonance has been recently developed by a task force from European Alzheimer's Disease ...Consortium (EADC) and Alzheimer's Disease Neuroimaging Initiative (ADNI). Our aim was to produce benchmark labels based on the HarP for manual segmentation. Methods Five experts of manual hippocampal segmentation underwent specific training on the HarP and segmented 40 right and left hippocampi from 10 ADNI subjects on both 1.5 T and 3 T scans. An independent expert visually checked segmentations for compliance with the HarP. Descriptive measures of agreement between tracers were intraclass correlation coefficients (ICCs) of crude volumes and similarity coefficients of three-dimensional volumes. Results Two hundred labels have been provided for the 20 magnetic resonance images. Intra- and interrater ICCs were >0.94, and mean similarity coefficients were 1.5 T, 0.73 (95% confidence interval CI, 0.71–0.75); 3 T, 0.75 (95% CI, 0.74–0.76). Conclusion Certified benchmark labels have been produced based on the HarP to be used for tracers' training and qualification.
Abstract Objective High power of pre-stimulus cortical alpha rhythms (about 8–12 Hz) underlies conscious perception in normal subjects. Here we tested the hypothesis that these rhythms are abnormal ...in persistent vegetative state (PVS) patients, who are awake but not aware of self and environment. Methods Clinical and resting-state, eyes-closed electroencephalographic (EEG) data were taken from a clinical archive. These data were recorded in 50 PVS subjects (level of cognitive functioning – LCF score: I–II) and in 30 cognitively normal subjects. Rhythms of interest were delta (2–4 Hz), theta (4–8 Hz), alpha 1 (8–10.5 Hz), alpha 2 (10.5–13 Hz), beta 1 (13–20 Hz), and beta 2 (20–30 Hz). Cortical sources were estimated by low-resolution electromagnetic tomography (LORETA). Based on LCF score at 3-months follow-up, PVS patients were retrospectively divided into three groups: 30 subjects who did not recover (NON-REC patients; follow-up LCF: I–II), 8 subjects classified as minimally conscious state patients (MCS patients; follow-up LCF: III–IV), and 12 subjects who recovered (REC patients; follow-up LCF: V–VIII). Results Occipital source power of alpha 1 and alpha 2 was high in normal subjects, low in REC patients, and practically null in NON-REC patients. A Cox regression analysis showed that the power of alpha source predicted the rate of the follow up recovery, namely the higher its power, the higher the chance to recover consciousness. Furthermore, the MCS patients showed intermediate values of occipital alpha source power between REC and NON-REC patients. Conclusions These results suggest that cortical sources of alpha rhythms are related to the chance of recovery at a 3-months follow-up in patients in persistent vegetative state. Significance Cortical sources of resting alpha rhythms might predict recovery in PVS patients.
The aim of this paper was to deepen understanding about the role played by brain plasticity in obtaining clinical recovery. Eighteen patients, who had recovered partially or totally from dysfunctions ...due to a monohemispheric infarction within the middle cerebral artery territory, underwent magnetoencephalographic (MEG) recordings of rolandic areas cerebral activity both in rest state (spectral power properties) and in response to the electrical stimulation of the contralateral median nerve (M20 and M30 cortical sources). MEG evaluation was performed in acute (T0: mean 5 days from ischemic attach) and post-acute phase (T1: median 6 months). At T1, all the inter-hemispheric asymmetries were reduced for both spontaneous and evoked activity parameters with respect to T0. In post-acute phase, lower cortical excitability, higher delta and theta power and lower spectral entropy were associated to a worse clinical state. An unusual recruitment–as revealed by an excessive inter-hemispheric asymmetry of M20 cortical source position–correlated with higher level of clinical amelioration in the patients who showed a partial recovery.
In addition to confirmative evidence that ‘normalization’ of neural activity in both the affected and unaffected hemispheres subtends best clinical recovery, present data provide support to the positive role of cerebral plasticity phenomena–i.e. unusual neural recruitments–to regain lost functions in those patients unable to achieve total recovery.
To explore temporal trends, geographic distribution, and socioeconomic determinants of scientific production in the field of cerebrovascular and cardiovascular disease (CCD) rehabilitation.
Citations ...from 1967 to 2008 were downloaded from the PubMed database. Core of the search strategy was the key word cardiovascular diseases in the Medical Subject Headings major field with the subheading rehabilitation. Journal Citation Reports was used to assign an impact factor (IF). Demographic and economic data were retrieved from the International Monetary Fund.
All articles retrieved were included in the bibliometric analysis.
The search strategy was validated on a random sample of the articles retrieved. The search quality reflected the level of error of the PubMed database.
Publications retrieved were 10,379 and have grown 8.6 times in 40 years, faster than the all-diseases rehabilitation field (7.8 times), with a particularly steep growth for cerebrovascular diseases in the last 15 years (5 times). However, in the last decade, the articles' quality (IF) decreased. From 1994 to 2008, 3466 citations were retrieved; 44.4% came from the European Union and 30.3% from the United States. The highest mean IF was reported for France (4.127). The United Kingdom and some relatively small northern European Union countries had the best ratio of IF (sum) to resident population or to gross domestic product. The most frequently used key word was stroke, and 3 journals (Archives of Physical Medicine and Rehabilitation, Clinical Rehabilitation, and Stroke) published one quarter of the articles.
The overall scientific production in the field of CCD rehabilitation showed a steep growth in the last decade, especially because of cerebrovascular research. In the same period, a decrease in the overall IF was observed. The European Union and the United States contributed 3 of every 4 articles in the field, although some Asian countries showed promising performance.
Ferric carboxymaltose (FCM) is a parenteral, dextran-free iron formulation designed to overcome the limitations of existing iron preparations. The main aim of this study was to retrospectively ...examine results obtained from a long period of FCM therapy in hemodialysis patients who have been previously treated with ferric gluconate (FX). Markers of iron metabolism, erythropoietin (EPO) doses, and effects on anemic status have been analysed.
The study was performed with a follow up period of 4 years, when patients were treated before with FX and then switched to FCM. A total of 25 patients were included in the study.
FCM increased transferrin saturation (TSAT) levels by 11.9% (
< 0.001) with respect to FX. Events of TSAT less than 20% were reduced during FCM. The monthly dose of EPO was reduced in the FCM period (-6,404.1 international unit IU; 95% confidence interval, -10,643.5 IU; -2,164.6 IU;
= 0.003), as well as the erythropoietin resistance index (
= 0.004). During the period with FCM, ferritin levels were higher than during FX (
< 0.001), while transferrin was reduced (
= 0.001).
During FCM treatment, minor doses of EPO were administered if compared to those delivered during FX therapy. Stable and on target levels of hemoglobin were maintained with better control of anemia through high levels of ferritin and TSAT.
Motor deficits affect patients with Alzheimer's disease only at later stages. Recent studies demonstrate that the primary motor cortex is affected by neuronal degeneration accompanied by the ...formation of amyloid plaques and neurofibrillary tangles. It is conceivable that neuronal loss is compensated by reorganization of the neural circuitries occurring along the natural course of the disease, thereby maintaining motor performances in daily living. Cortical motor output to upper limbs was tested via motor‐evoked potentials from forearm and hand muscles elicited by transcranial magnetic stimulation of motor cortex in 16 patients with mild Alzheimer's disease without motor deficits. Motor cortex excitability was increased, and the center of gravity of motor cortical output, as represented by excitable scalp sites, showed a frontal and medial shift, without correlated changes in the site of maximal excitability (hot‐spot). This may indicate functional reorganization, possibly after the neuronal loss in motor areas. Hyperexcitability might be caused by a dysregulation of the intracortical GABAergic inhibitory circuitries and selective alteration of glutamatergic neurotransmission. Such findings suggest that motor cortex hyperexcitability and reorganization allows prolonged preservation of motor function during the clinical course of Alzheimer's disease.
Evidence suggests that an alteration in cerebral hemodynamics plays a relevant role in the occurrence of stroke in patients with carotid occlusion. The purpose of the present study was to evaluate ...the relationships among baseline characteristics, type and number of collateral pathways, cerebral vasomotor reactivity (VMR), and outcome of patients with carotid occlusion.
One hundred four patients with symptomatic or asymptomatic internal carotid artery occlusion were followed up prospectively for a median period of 24 months. Cerebral VMR to apnea was calculated with transcranial Doppler ultrasonography by means of the breath-holding index (BHI) in the middle cerebral arteries. The patency of the 3 major intracranial collateral vessels was also evaluated.
During the follow-up period, 18 patients experienced an ischemic stroke ipsilateral to internal carotid artery occlusion. Among factors considered, only older age, number of collateral pathways, and BHI values in the middle cerebral artery ipsilateral to the occluded side were significantly associated with the risk of ipsilateral stroke (P<0.001, P=0.008, and P<0.001, respectively; multiple Cox regression analysis). A normal VMR and favorable prognosis characterized patients with full collateral development; in this group, no patient experienced an ischemic event. On the other hand, an impaired VMR and increased probability of experiencing a stroke were found in patients without collateral pathways; the annual risk of ipsilateral stroke in this group was 32.7%. Patients with 1 or 2 collateral pathways showed a different VMR ranging from normal to strongly reduced BHI values. The ipsilateral stroke event risk was 17.5% in patients with 1 collateral vessel and 2.7% in patients with 2 collateral pathways. In this case, the risk of cerebrovascular events occurring during the follow-up period was significantly related to VMR.
These data suggest that cerebral hemodynamic status in patients with carotid occlusive disease is influenced by both individual anatomic and functional characteristics. The planning of strategies to define the risk profile and any attempt to influence patients' outcome should be based on the evaluation of the intracranial hemodynamic adaptive status, with particular attention to the number of collateral vessels and the related VMR.
It is a common feeling that girls speak earlier than boys; however, whether or not there are gender differences in early language acquisition remains controversial. The present paper aims to review ...the research on gender effects in early language acquisition and development, to determine whether, and from which age, an advantage for girls does eventually emerge. The focus is on the production of actions and communicative gestures, and early lexical comprehension and production, by girls and boys. The data from various studies that were conducted with direct and indirect tools suggest that some gender differences in actions, gesture, and lexical development depend on the interactions of different factors. Studies differ in terms of age ranges, sample sizes, and tools used, and the girl advantage is often slight and/or not evident at all ages considered. Statistical significance for gender differences appears to depend on the greater individual variability among boys, with respect to girls, which results in a greater number of boys classified as children with poor verbal ability. Biological (e.g., different maturational rates), neuropsychological (e.g., different cognitive strategies in solving tasks), and cultural (e.g., differences in the way parents relate socially to boys and girls) factors appear to interact, to create feedback loops of mutual reinforcement.
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