Biofeedback fixation training method for improving eccentric vision in patients with loss of foveal function secondary to different maculopathies

International Ophthalmology - Fixation stability (FS) of the preferred retinal locus (PRL) may be improved by biofeedback fixation training (BFT) with microperimetry. Such training can be done on...     

Prevalence of patent foramen ovale in ischemic stroke in Italy: the SISIFO study

Patent foramen ovale (PFO) is a common congenital anatomical defect in the general population with a mean prevalence of 20 %. Transcranial Doppler sonography and echocardiography, both with infusion of agitated saline as an echo contrast, have been introduced for the diagnosis of PFO. Transesophageal echocardiography is considered the gold standard. Several studies have suggested an association between cryptogenetic stroke and PFO, but the role of this condition as a risk factor for stroke is still debated. The aims of this prospective multicentre study are the evaluation of PFO prevalence in the whole ischemic stroke population and the identification of a stroke recurrence profile risk in patients with PFO. All consecutive patients admitted for acute ischemic stroke and with a confirmed diagnosis at discharge are eligible cases for the study. Demographic and vascular risk factors are registered. Clinical severity is summarized by the National Institute of Health stroke scale. Echocardiographic and transcranial studies are performed in each patient to detect the presence of PFO. Prevalence of PFO will be calculated with 95 % CIs. Univariate analysis will be performed to detect the correlation of PFO with different registered factors and multivariable analysis with PFO as independent variable. The present study should contribute to better identify the role of PFO in ischemic stroke risk and recurrence-related events. Qualifying findings of the study are represented by the high number of enrolled patients, the prospective methodology of the study and the presence of secondary instrumental endpoints.     

Validation of the Italian version of Parkinson’s Disease-Cognitive Rating Scale (PD-CRS)

Cognitive impairment (CI) is a frequent feature associated with both early and advanced stages of Parkinson’s disease (PD). An evaluation of cognitive functions is relevant to identify those parkinsonians at risk of developing dementia. In the present study, the Italian version of Parkinson’s Disease-Cognitive Rating Scale (PD-CRS) assessing fronto-subcortical and cortical cognitive functions in PD was validated in 387 parkinsonians and was used to test the empirical validity of the item 1.1 (cognitive impairment) of the Italian version of MDS-UPDRS as screening tool for CI in PD. PD-CRS was free from floor and ceiling effect. The mean PD-CRS score was 76.1 (mean cortical score, 24.5 ± 4.6; mean subcortical score, 51.5 ± 17.5). The internal consistency was satisfactory (α = 0.89); corrected item-total correlation was 0.570 (naming) to 0.696 (working memory). The correlation between PD-CRS and part I–IV of MDS-UPDRS was weak. The low agreement between classification of PD sample into patients with mild cognitive impairment (PD-MCI), dementia (PD-D) and normal cognition (PD-NC) according to scores of item 1.1 and classification according to cutoff scores of PD-CRS for PD-MCI, PD-D and PD-NC indicated a poor empirical validity of item 1.1 of MDS-UPDRS as cognitive screening tool for CI in PD (Κ = 0.114; weighted Κ = 0.17; SE of Κ = 0.038; 95 % confidence interval from 0.040 to 0.1895). The Italian version of PD-CRS is an easy, consistent and valid tool for assessment of the cognitive cortical and subcortical impairments in PD.     

The Lindblom roller.

Neuropathic pain is caused by injury of the peripheral or central nervous system. The neurological examination of the sensory system in neuropathic pain patients guides the anatomical localization of the injury. Among the sensory modalities to be tested, priority should be given to those subserved by small peripheral sensory fibers or by the spinothalamic tract that most commonly are abnormal in neuropathic pain patients. Testing of cold and warm perception was traditionally carried out in the clinic using tubes filled with water at different temperatures, a cumbersome method that has limited the routine examination of these sensory modalities. The Lindblom roller offers a practical and effective method of readily testing temperature perception and is among the best available clinical tools for delineating the anatomical boundaries of a sensory abnormality. Routinely use of the Lindblom roller shall be standard bedside clinical assessment of neuropathic pain patients. To exemplify this statement we describe two patients affected by complex and fluctuating painful sensory abnormalities caused by an extradural mass compressing the spinal cord. The level of the injury was readily localized with a roller kept at room temperature.     

A switch from inter‐ocular to inter‐hemispheric suppression following monocular deprivation in the rat visual cortex

Binocularity is a key property of primary visual cortex (V1) neurons that is widely used to study synaptic integration in the brain and plastic mechanisms following an altered visual experience. However, it is not clear how the inputs from the two eyes converge onto binocular neurons, and how their interaction is modified by an unbalanced visual drive. Here, using visual evoked potentials recorded in the juvenile rat V1, we report evidence for a suppressive mechanism by which contralateral eye activity inhibits responses from the ipsilateral eye. Accordingly, we found a lack of additivity of the responses evoked independently by the two eyes in the V1, and acute silencing of the contralateral eye resulted in the enhancement of ipsilateral eye responses in cortical neurons. We reverted the relative cortical strength of the two eyes by suturing the contralateral eye shut [monocular deprivation (MD)]. After 7 days of MD, there was a loss of interocular suppression mediated by the contralateral, deprived eye, and weak inputs from the closed eye were functionally inhibited by interhemispheric callosal pathways. We conclude that interocular suppressive mechanisms play a crucial role in shaping normal binocularity in visual cortical neurons, and a switch from interocular to interhemispheric suppression represents a key step in the ocular dominance changes induced by MD. These data have important implications for a deeper understanding of the key mechanisms that underlie activity‐dependent rearrangements of cortical circuits following alteration of sensory experience.