Polarity-Dependent Misperception of Subjective Visual Vertical during and after Transcranial Direct Current Stimulation (tDCS)

Pathologic tilt of subjective visual vertical (SVV) frequently has adverse functional consequences for patients with stroke and vestibular disorders. Repetitive transcranial magnetic stimulation (rTMS) of the supramarginal gyrus can produce a transitory tilt on SVV in healthy subjects. However, the effect of transcranial direct current stimulation (tDCS) on SVV has never been systematically studied. We investigated whether bilateral tDCS over the temporal- parietal region could result in both online and offline SVV misperception in healthy subjects. In a randomized, sham-controlled, single-blind crossover pilot study, thirteen healthy subjects performed tests of SVV before, during and after the tDCS applied over the temporal- parietal region in three conditions used on different days: right anode/left cathode; right cathode/left anode; and sham. Subjects were blind to the tDCS conditions. Montage-specific current flow patterns were investigated using computational models. SVV was significantly displaced towards the anode during both active stimulation conditions when compared to sham condition. Immediately after both active conditions, there were rebound effects. Longer lasting after-effects towards the anode occurred only in the right cathode/left anode condition. Current flow models predicted the stimulation of temporal-parietal regions under the electrodes and deep clusters in the posterior limb of the internal capsule. The present findings indicate that tDCS over the temporal-parietal region can significantly alter human SVV perception. This tDCS approach may be a potential clinical tool for the treatment of SVV misperception in neurological patients

Normative data for human postural vertical: A systematic review and meta-analysis.

Perception of verticality is required for normal daily function, yet the typical human detection error range has not been well characterized. Vertical misperception has been correlated with poor postural control and functionality in patients after stroke and after vestibular disorders. Until now, all the published studies that assessed Subjective Postural Vertical (SPV) in the seated position used small groups to establish a reference value. However, this sample size does not represent the healthy population for comparison with conditions resulting in pathological vertical. Therefore, the primary objective was to conduct a systematic review with meta-analyses of Subjective Postural Vertical (SPV) data in seated position in healthy adults to establish the reference value with a representative sample. The secondary objective was to investigate the methodological characteristics of different assessment protocols of SPV described in the literature. A systematic literature search was conducted using Medline, EMBASE, and Cochrane libraries. Mean and standard deviation of SPV in frontal and sagittal planes were considered as effect size measures. Sixteen of 129 identified studies met eligibility criteria for our systematic review (n = 337 subjects in the frontal plane; n = 187 subjects in sagittal plane). The meta-analyses measure was estimated using the pooled mean as the estimator and its respective error. Mean reference values were 0.12°±1.49° for the frontal plane and 0.02°±1.82° for the sagittal plane. There was a small variability of the results and this systematic review resulted in representative values for SPV. The critical analysis of the studies and observed homogeneity in the sample suggests that the methodological differences used in the studies did not influence SPV assessment of directional bias in healthy subjects. These data can serve as a reference for clinical studies in disorders of verticality

Intravenous rtPA versus mechanical thrombectomy in acute ischemic stroke: A historical cohort in Joinville, Brazil

Groundbreaking results concerning ischemic stroke (IS) hyperacute treatment worldwide were published in 2014 and 2015. We aimed to compare functional status after 3 months in patients treated with intra-arterial thrombectomy (IAT) and those treated with intravenous thrombolysis (IVT) alone in Joinville, Brazil.From the Joinville Stroke Registry, we extracted and compared all consecutive IVT patients treated with r-tPA within 4.5 h in the period 2009–2011 versus all consecutive IAT treated within 6 h with the Solitaire FR device plus IVT in the period 2012–2014.We registered 82 patients in the IVT group and 31 patients in the IAT group. At hospital admission, patients in the IAT group were significantly younger (p < 0.001), had a higher educational level (p = 0.001), had a slightly higher prevalence of atrial fibrillation (p = 0.057) and had more severe strokes measured by the NIH stroke scale (p = 0.011). After 90 days, 45% of patients in the IAT group and 27% in the IVT group were independent (0–1 points) according to the modified Rankin scale (adjusted odds ratio: 4.53; 95% CI: 1.22 to 16.75). Symptomatic hemorrhage was diagnosed in 10% of patients in both groups (p = 1.0). The 90-day case-fatality was 39% (32/82) in the IVT group and 26% (8/31) in the IAT group (p = 0.27). In this small cohort, a greater rate of functional independence was achieved in patients treated with IAT plus IVT, compared with patients treated with IVT lysis alone. Our “real-world” findings are consistent with results of controlled, randomized clinical trials. Keywords: Ischemic stroke, Stroke thrombolysis, Mechanical thrombectomy, Cohor

Verticality Perceptions Associate with Postural Control and Functionality in Stroke Patients.

Deficits of postural control and perceptions of verticality are disabling problems observed in stroke patients that have been recently correlated to each other. However, there is no evidence in the literature confirming this relationship with quantitative posturography analysis. Therefore, the objectives of the present study were to analyze the relationship between Subjective Postural Vertical (SPV) and Haptic Vertical (HV) with posturography and functionality in stroke patients. We included 45 stroke patients. The study protocol was composed by clinical interview, evaluation of SPV and HV in roll and pitch planes and posturography. Posturography was measured in the sitting and standing positions under the conditions: eyes open, stable surface (EOSS); eyes closed, stable surface (ECSS); eyes open, unstable surface (EOUS); and eyes closed, unstable surface (ECUS). The median PV in roll plane was 0.34° (-1.44° to 2.54°) and in pitch plane 0.36° (-2.72° to 2.45°). The median of HV in roll and pitch planes were -0.94° (-5.86° to 3.84°) and 3.56° (-0.68° to 8.36°), respectively. SPV in the roll plane was correlated with all posturagraphy parameters in sitting position in all conditions (r = 0.35 to 0.47; p < 0.006). There were moderate correlations with the verticality perceptions and all the functional scales. Linear regression model showed association between speed and SPV in the roll plane in the condition EOSS (R2 of 0.37; p = 0.005), in the condition ECSS (R2 of 0.13; p = 0.04) and in the condition EOUS (R2 of 0.22; p = 0.03). These results suggest that verticality perception is a relevant component of postural control and should be systematically evaluated, particularly in patients with abnormal postural control

Posturographic assessment of stroke patients.

<p>Data described as mean ± standard deviation.</p

Correlation between posturographic parameters in roll and pitch planes for each condition in standing and sitting position.

<p>Correlation between posturographic parameters in roll and pitch planes for each condition in standing and sitting position.</p

Correlation between SPV and posturographic parameters in roll plane at sitting position.

<p>Correlation between SPV and posturographic parameters in roll plane at sitting position.</p

Correlations between clinical and functional scales and SPV and HV in stroke patients.

<p>Correlations between clinical and functional scales and SPV and HV in stroke patients.</p