Ipsilesional Side Research Articles

Focal traumatic brain injury induces neuroplastic molecular responses in lumbar spinal cord.

Background/Objectives:Motor impairment induced by traumatic brain injury (TBI) may be mediated through changes in spinal molecular systems regulating neuronal plasticity. We assessed whether a focal controlled cortical impact (CCI) TBI in the rat alters expression of the Tgfb1, c-Fos, Bdnf, and Gap43 neuroplasticity genes in lumbar spinal cord.Approach/Methods:Adult male Sprague-Dawley rats (n = 8) were subjected to a right-side CCI over the anterior sensorimotor hindlimb representation area or sham-injury (n = 8). Absolute expression levels of Tgfb1, c-Fos, Bdnf, and Gapd43 genes were measured by droplet digital PCR in ipsi-and contralesional, dorsal and ventral quadrants of the L4 and L5 spinal cord. The neuronal activity marker c-Fos was analysed by immunohistochemistry in the dorsal L4 and L5 segments. The contra- vs. ipsilesional expression pattern was examined as the asymmetry index, AI.Results:The Tgfb1 mRNA levels were significantly higher in the CCI vs. sham-injured rats, and in the contra- vs. ipsilesional dorsal domains in the CCI group. The number of c-Fos-positive cells was elevated in the L4 and L5 segments; and on the contralesional compared to the ipsilesional side in the CCI group. The c-Fos AI in the dorsal laminae was significantly increased by CCI.Conclusions:The results support the hypothesis that focal TBI induces plastic alterations in the lumbar spinal cord that may contribute to either motor recovery or maladaptive motor responses.

Cerebellar repetitive transcranial magnetic stimulation restores pharyngeal brain activity and swallowing behaviour after disruption by a cortical virtual lesion.

Key points Despite evidence that the human cerebellum has an important role in swallowing neurophysiology, the effects of cerebellar stimulation on swallowing in the disrupted brain have not been explored.In this study, for the first time, the application of cerebellar neurostimulation is characterized in a human model of disrupted swallowing (using a cortical virtual lesion).It is demonstrated that cerebellar stimulation can reverse the suppressed activity in the cortical swallowing system and restore swallowing function in a challenging behavioural task, suggesting the findings may have important therapeutic implications. Repetitive transcranial magnetic stimulation (rTMS) can alter neuronal activity within the brain with therapeutic potential. Low frequency stimulation to the ‘dominant’ cortical swallowing projection induces a ‘virtual‐lesion’ transiently suppressing cortical excitability and disrupting swallowing behaviour. Here, we compared the ability of ipsi‐lesional, contra‐lesional and sham cerebellar rTMS to reverse the effects of a ‘virtual‐lesion’ in health. Two groups of healthy participants (n = 15/group) were intubated with pharyngeal catheters. Baseline pharyngeal motor evoked potentials (PMEPs) and swallowing performance (reaction task) were measured. Participants received 10 min of 1 Hz rTMS to the pharyngeal motor cortex which elicited the largest PMEPs to suppress cortical activity and disrupt swallowing behaviour. Over six visits, participants were randomized to receive 250 pulses of 10 Hz cerebellar rTMS to the ipsi‐lesional side, contra‐lesional side or sham while assessing PMEP amplitude or swallowing performance for an hour afterwards. Compared to sham, active cerebellar rTMS, whether administered ipsi‐lesionally (P = 0.011) or contra‐lesionally (P = 0.005), reversed the inhibitory effects of the cortical ‘virtual‐lesion’ on PMEPs and swallowing accuracy (ipsi‐lesional, P < 0.001, contra‐lesional, P < 0.001). Cerebellar rTMS was able to reverse the disruptive effects of a ‘virtual lesion’. These findings provide evidence for developing cerebellar rTMS into a treatment for post‐stroke dysphagia.

Manual function of the unaffected upper extremity can affect functional outcome after stroke.

Traditionally, motor deficits of ipsilesional side, generally considered as the unaffected side, have been investigated less and the influence of the impairment is unknown. To evaluate the association between the manual function test (MFT) of nonparetic limb and poststroke functional outcome. We conducted a retrospective analysis of 71 hemiplegic patients with stroke. MFT on both sides was routinely measured at admission and 1 month later after admission by an experienced occupational therapist. The parameters of functional outcome after stroke were measured with the total score of functional independence measure (FIM) and the self-care subscore of FIM. Age, initial cognitive function, and MFT of the affected hand and unaffected hand were each significant factors for independently predicting short-term functional outcome after stroke. Linear regression analysis showed that initial MFT score of unaffected side is a significant predictor for 1 month follow-up subscore FIM (P<0.0001) and total FIM score (P<0.0001). Our findings suggests that initial MFT score of the nonparetic side has a significant correlation with functional outcome. Therefore, it is important to conduct MFT on the nonparetic side as well as the paretic side. Furthermore, it is necessary to undergo rehabilitation therapy on the nonparetic side.

Sensory-motor impairments of ipsilesional extremities and its impact on activity limitations following stroke

Background/Aims Stroke can result in various motor and sensory impairments on contralesional as well as ipsilesional limbs. This study examined the impact on activity limitations as a result of sensory and motor impairments of ipsilesional limbs following stroke. Methods A cross-sectional study was used to assess 50 adults with stroke (acute: n=6, subacute: n=10, chronic: n=34) and 50 age- and gender-matched typically healthy adults. The Modified Ashworth Scale, the Brunnstrom Approach, Nottingham Sensory Assessment, Star Cancellation Test, Right-Left Orientation Test, Trunk Impairment Scale, Single Leg Stance Test, and the Fugl Mayer Assessment were used to measure outcomes for ipsilesional side impairments. Activity limitations were scored using the Wisconsin Gait Scale and the Motor Assessment Scale. Results A comparison of all impairments: tonal, voluntary control, sensation, perception, sitting and standing balance, and coordination of the ipsilesional extremity of persons with hemiparesis with corresponding extremity of typically healthy adults using unpaired t-test, showed significant impairment (P&lt;0.05). Every participant with stroke had at least one impairment on their ipsilesional side, with 8% of participants having only one impairment, 36% had two impairments, 28% had three impairments, 18% had four impairments, 8% had five impairments and 2% had all six impairments on their ipsilesional side. The percentage of participants with stroke presenting with trunk impairment was highest (100%) and that of voluntary control impairment was lowest (24%) on their ipsilesional side. The relationship between identified impairments and activity limitations was calculated using Pearson’s correlation at 0.05 level, which showed a moderate negative correlation with the Wisconsin Gait Scale and a moderate positive correlation with the Motor Assessment Scale. Conclusions Ipsilesional impairments present in people with hemiparesis have a significant impact on the activity limitation; hence it is necessary to address ipsilesional impairments along with contralesional impairments.

Disrupted functional connectivity and activity in the white matter of the sensorimotor system in patients with pontine strokes.

White matter (WM) blood oxygenation level-dependent (BOLD) signals are reported to be related to neural activity. However, sensitivity of WM BOLD signals to disease remains unclear. To investigate WM BOLD signal changes, directional variations of resting-state correlations in sensorimotor system in patients with pontine strokes, and to determine the relationship between WM BOLD signals and motor deficits. Prospective. Ethical approval was obtained from the local Ethics Committee and each participant gave written informed consent. Sixteen patients with focal pontine lesions and 16 age-matched control subjects were included. 3.0T T1 -weighted anatomic images using a 3D magnetization-prepared rapid gradient-echo sequence. Resting-state fMRI images using gradient-echo echo-planar imaging sequence. Diffusion-weighted images using single-shot spin-echo diffusion echo-planar imaging. Relevant WM tracts in the sensorimotor system by region of interest-wise analysis were identified. Power spectra of BOLD signals and anisotropy of resting-state correlations were measured in sensorimotor system and compared between two groups. Their relationships with clinical scores were analyzed. Two-sample t-test; partial correlation analysis. Power spectra of BOLD signals in nerve tracts on the ipsilesional side were significantly decreased (P < 0.05). Compared with that in healthy subjects, the anisotropy of resting-state correlations along identified WM tracts was decreased in the thalamus-dorsolateral prefrontal cortex bundle on the contralesional side, and all nerve tracts on the ipsilesional side. Partial least squares regression analysis showed the predicted outcome scores correlated significantly with actual Fugl-Meyer scores (R2 = 0.944, P = 0.013). Our findings suggest that disrupted activity and functional connectivity in WM areas of the sensorimotor system can be detected in pontine strokes, and may serve as a biomarker for motor function prediction. 2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;49:478-486.

Impact of clinical severity of stroke on the severity and recovery of visuospatial neglect.

Background and purposeThere is growing evidence that visuospatial neglect (VSN) is associated with lower functional performance in other modalities and is not restricted to the lesioned hemisphere alone, and may also affect the non-lesioned hemisphere in severe first-ever strokes. We aimed to investigate the longitudinal association between the severity of VSN, as reflected by the extent of ipsilesional and contralesional spatial attention deficit, and clinical severity of stroke.MethodsThis is a secondary data analysis with merged data from two prospective cohort studies. Resulting in 90 patients and 8 longitudinal measurements at 1, 2, 3, 4, 5, 8, 12, and 26 weeks post-stroke onset. A letter cancellation test (LCT) was used as the primary outcome measure to demonstrate presence and severity of VSN. The clinical severity of stroke was classified using the Bamford Classification.ResultsNo significant association between clinical severity and the number of ipsilesional, as well as contralesional, omissions on the LCT was observed. Recovery of VSN at the contralesional hemiplegic, as well as ipsilesional non-hemiplegic side, was only dependent on ‘time’ as a reflection of spontaneous neurobiological recovery post-stroke. The recovery of the ipsilesional extension of VSN was significantly slower for the total anterior circulation infarct (TACI) group compared to the non-TACI group.ConclusionsLarger strokes have a significant negative impact on recovery of visual attention at the non-hemiplegic side. No clinical determinants that regulate spontaneous time-dependent recovery of VSN were found. While early ‘stroke severity’ has been regarded as a strong predictor of functional outcome at a group level, other prognostic factors (demographic, stroke related) need to be determined.Clinical trial registrationEXPLICIT-stroke Trial: http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=1424Stroke Intensity Trial: http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=1665

Anticipatory postural adjustments in the shoulder girdle in the reach movement performed in standing by post-stroke subjects

After a stroke in middle cerebral artery territory, there is a high probability of dysfunction of the ventromedial pathways, mainly related with postural control mechanisms such as the anticipatory postural adjustments (APAs). According to neuroanatomical knowledge, these pathways have a predominant ipsilesional disposition, which justifies a bilateral postural control dysfunction, often neglected in rehabilitation. In order to assess this bilateral postural control dysfunction, electromyography activity was assessed in eight post-stroke and 10 healthy individuals in the anterior deltoids, the superior and lower trapezius, and the latissimus dorsi as they reached for a bottle with both upper limbs separately at a self-selected velocity and fast velocity while standing associated with trunk kinematics analysis. Through this analysis it was possible to compare the timing of APAs in scapular muscles between sides in post-stroke and with healthy individuals, and to verify if there is a relation between the timing and the displacement of the trunk in the temporal window of the APAs. Indeed, post-stroke individuals show a delayed activation of APAs on scapular girdle muscles on both ipsilesional and contralesional sides, which were not reflected in the trunk displacement.

Genetic and Environmental Contributions to Variation in the Posterior Communicating Collaterals of the Circle of Willis.

Variation in blood flow mediated by the posterior communicating collateral arteries (PComs) contributes to variation in the severity of tissue injury in obstructive disease. Evidence in animals and humans indicates that differences in the extent of PComs, i.e., their anatomic lumen diameter and whether they are present bilaterally, unilaterally, or absent, are a major factor. These differences arise during development since they are present at birth. However, the causal mechanisms are unknown. We used angiography after maximal dilation to examine involvement of genetic, environmental, and stochastic factors. The extent of PComs varied widely among seven genetically diverse strains of mice. Like pial collaterals in the microcirculation, aging and hypertension reduced PCom diameter, while in contrast, obesity, hyperlipidemia, metabolic syndrome, and diabetes mellitus had no effect. Naturally occurring intrauterine growth restriction had no effect on extent of PCom or pial collaterals in the adult. The number and diameter of PComs evidenced much larger apparent stochastic-dependent variation than pial collaterals. In addition, both PComs underwent flow-mediated outward remodeling after unilateral permanent MCA occlusion that varied with genetic background and was greater on the ipsilesional side. These findings indicate that variation in the number and diameter of PCom collateral arteries arises from stochastic factors and naturally occurring genetic variants that differ from those that cause variation in pial collateral arterioles. Environmental factors also contribute: aging and hypertension reduce PCom diameter. Our resultssuggest possible sources of variation of PComs in humans and provide information relevant when studying mouse models of occlusive cerebrovascular disease.

Dissociable components of spatial neglect associated with frontal and parietal lesions

Spatial neglect is a complex neuropsychological disorder, in which patients fail to detect and respond to contralesional stimuli. Recent studies suggest that these symptoms may reflect a combination of different component deficits, associated with different lesion substrates. Thus, damage to right lateral prefrontal and inferior parietal regions produce different degrees of left neglect on cancellation and line bisection tasks, respectively. Here we tested for dissociable behaviors across two tasks designed to assess distinct cognitive processes possibly mediating such components, in 14 patients with right focal lesion in either the frontal or parietal lobe. In the “distractor filtering” task, patients had to respond to a visual target presented centrally, with or without a lateralized distractor. Only frontal-lesioned patients showed a marked slowing of reaction times when a central target appeared with a simultaneous right distractor (compared to center and left distractor). In the “spatial coding” task, patients had to detect a target among successive visual stimuli presented horizontally with three sequence conditions (regular/predictive or irregular/non-predictive). Only parietal-lesioned patients were unable to benefit from the predictability of the target position, with similar reaction times across all sequence conditions. By contrast, frontal patients showed faster reaction times on trials with a regular succession of stimuli (compared to random order). Taken together, these results suggest that frontal damage may contribute to left inattention by disrupting top-down control and resistance to distractors on the ipsilesional side, whereas parietal damage may disrupt the maintenance of stable locations in space across gaze shifts or time. This further supports the notion that left neglect may arise as a combined breakdown or impaired connectivity between frontal and parietal mechanisms involved (respectively) in the selective control and memory storage components of spatial attention.

Optimal visuo-vestibular integration for self-motion perception in patients with unilateral vestibular loss

Unilateral vestibular loss (UVL) is accompanied by deficits in processing of visual and vestibular self-motion cues. The present study examined whether multisensory integration of these two types of information is, nevertheless, intact in such patients. Patients were seated on a rotating platform with a screen simulating 3D rotation in front of them and asked to judge the relative magnitude of two successive rotations in the yaw plane in three conditions: vestibular stimulation, visual stimulation and bimodal stimulation (congruent stimuli from both modalities together). Similar to findings in healthy controls, UVL patients exhibited optimal multisensory integration during both ipsi- and contralesional rotations. The benefit of multisensory integration was more pronounced on the ipsilesional side. These results show that visuo-vestibular integration for passive self-motion is automatic and suggests that it functions without additional cognitive mechanisms, unlike more complex multisensory tasks such as postural control and spatial navigation, previously shown to be impaired in UVL patients.

The Reticulospinal Pathway Does Not Increase Its Contribution to the Strength of Contralesional Muscles in Stroke Survivors as Compared to Ipsilesional Side or Healthy Controls.

Startling acoustic stimulation (SAS), via activation of reticulospinal (RS) pathways, has shown to increase muscle strength in healthy subjects. We hypothesized that, given RS hyperexcitability in stroke survivors, SAS could increase muscle strength in stroke survivors. The objective was to quantify the effect of SAS on maximal and sub-maximal voluntary elbow flexion on the contralesional (impaired) side in stroke survivors as compared to ipsilesional (non-impaired) side and healthy controls. Thirteen hemiparetic stroke survivors and 12 healthy subjects volunteered for this investigation. Acoustic stimulation was given at rest, during ballistic maximal and sustained sub-maximal isometric elbow contractions using low (80 dB) and high intensity sound (105 dB). The effect of acoustic stimuli was evaluated from EMG and force recordings. Prevalence of acoustic startle reflex with shorter latency in the impaired biceps was greater as compared to the response in the non-impaired side of stroke subjects and in healthy subjects. Delivery of SAS resulted in earlier initiation of elbow flexion and greater peak torque in healthy subjects and in stroke subjects with spastic hemiplegia during maximal voluntary elbow flexion tasks. During sub-maximal elbow flexion tasks, SAS-induced force responses were slightly greater on the impaired side than the non-impaired side. However, no statistically significant difference was found in SAS-induced responses between impaired and non-impaired sides at maximal and sub-maximal elbow flexion tasks. The findings suggest RS hyperexcitability in stroke survivors with spastic hemiplegia. The results of similar SAS-induced responses between healthy and stroke subjects indicate that RS projections via acoustic stimulation are not likely to contribute to muscle strength for stroke survivors to a significant extent.

Clinical and video head impulse test in the diagnosis of posterior circulation stroke presenting as acute vestibular syndrome inthe emergency department.

Head impulse test (HIT) is the critical bedside examination which differentiates vestibular neuritis (VN) from posterior circulation stroke (PCS) in acute vestibular syndrome (AVS). Video-oculography based HIT (vHIT) may have aadditional strength in making the differentiation. Patients admitted to the emergency department of a tertiary-care medical center with AVS were studied. An emergency specialist and a neurologist performed HIT. vHIT was conducted by an neuro-otology research fellow. Forty patients 26 male, 14 female with a mean age of 49 years were included in the analyses. Final diagnoses were VN in 24 and PCS in 16 patients.In the VN group, clinical HIT was assessed as abnormal in 19(80%) cases by the emergency specialist and in 20(83%) by the neurologist. In all PCS patients, HIT was recorded as normal both by the emergency specialist and the neurologist (100%).On vHIT, patients with VN had significantly low gain values for both the ipsilesional and contralesional sides when compared with the healthy controls, with significantly lower figures for the ipsilesional side (p < 0.001). All patients in this group had normal DWI-MRI.PCS patients had bilaterally low gain (p < 0.05) on vHIT. However, gain asymmetry was not significant. Subgroup analyses according to presence of brainstem involvement revealed bilateral low gain (p < 0.05) in patients with brainstem infarction (anterior inferior cerebellar artery-posterior inferior cerebellar artery stroke, AICA-PICA stroke) whereas patients with pure cerebellar infarction (posterior inferior cerebellar artery-superior cerebellar artery stroke, PICA-SCA stroke) had gain values similar to healthy controls.With a gain cut-off ≤0.75 and gain asymmetry cut-off ≥17%, as determined by ROC analysis, 100% of PCS patients and 80% of VN patients were correctly diagnosed. Clinical HIT, either performed by an emergency specialist or neurologist is equivalent to vHIT gain and gain asymmetry analysis as conducted by neuro-otologist in the diagnosis of PCS, albeit mislabeling about 20% of VN patients. vHIT does not appear to yield additional diagnostic information. These findings indicate the strength of clinical HIT. Pure gain-based vHIT analysis seems limited and needs to be incorporated with saccade analysis.

Persistent neglect in everyday life

Unilateral Spatial Neglect (USN) is a multifarious syndrome ( Cubelli, 2017 ), aspects of which could be long lasting either as poor performance on individual diagnostic tests ( Farne et al., 2004 ), in subclinical forms ( Colombo et al., 1982 ) or as a marked preference for the ipsilesional side even in the absence of overt omissions ( Mattingley, et al., 1994 ). The assessment of USN, both when first diagnosed and in the follow-ups, is carried out by means of standard tests. However, these tests are not equipoise in detecting USN ( Halligan et al., 1989 ); they can present double dissociations ( Halligan and Marshall, 1992 ) and can be differentially sensitive to compensation strategies ( Campbell and Oxbury, 1976 ). Therefore, it is widely assumed that the more tests are used, the higher is the probability of detecting signs of initial or residual USN ( Azouvi et al., 2006 ). Nevertheless, we have observed a dissociation between normal performance on all formal tests of a very large battery and clear signs of USN in everyday tasks and actions.

Neural Patterns of Reorganization after Intensive Robot-Assisted Virtual Reality Therapy and Repetitive Task Practice in Patients with Chronic Stroke.

Several approaches to rehabilitation of the hand following a stroke have emerged over the last two decades. These treatments, including repetitive task practice (RTP), robotically assisted rehabilitation and virtual rehabilitation activities, produce improvements in hand function but have yet to reinstate function to pre-stroke levels—which likely depends on developing the therapies to impact cortical reorganization in a manner that favors or supports recovery. Understanding cortical reorganization that underlies the above interventions is therefore critical to inform how such therapies can be utilized and improved and is the focus of the current investigation. Specifically, we compare neural reorganization elicited in stroke patients participating in two interventions: a hybrid of robot-assisted virtual reality (RAVR) rehabilitation training and a program of RTP training. Ten chronic stroke subjects participated in eight 3-h sessions of RAVR therapy. Another group of nine stroke subjects participated in eight sessions of matched RTP therapy. Functional magnetic resonance imaging (fMRI) data were acquired during paretic hand movement, before and after training. We compared the difference between groups and sessions (before and after training) in terms of BOLD intensity, laterality index of activation in sensorimotor areas, and the effective connectivity between ipsilesional motor cortex (iMC), contralesional motor cortex, ipsilesional primary somatosensory cortex (iS1), ipsilesional ventral premotor area (iPMv), and ipsilesional supplementary motor area. Last, we analyzed the relationship between changes in fMRI data and functional improvement measured by the Jebsen Taylor Hand Function Test (JTHFT), in an attempt to identify how neurophysiological changes are related to motor improvement. Subjects in both groups demonstrated motor recovery after training, but fMRI data revealed RAVR-specific changes in neural reorganization patterns. First, BOLD signal in multiple regions of interest was reduced and re-lateralized to the ipsilesional side. Second, these changes correlated with improvement in JTHFT scores. Our findings suggest that RAVR training may lead to different neurophysiological changes when compared with traditional therapy. This effect may be attributed to the influence that augmented visual and haptic feedback during RAVR training exerts over higher-order somatosensory and visuomotor areas.

Brain plasticity following MI-BCI training combined with tDCS in a randomized trial in chronic subcortical stroke subjects: a preliminary study

Brain-computer interface-assisted motor imagery (MI-BCI) or transcranial direct current stimulation (tDCS) has been used in stroke rehabilitation, though their combinatory effect is unknown. We investigated brain plasticity following a combined MI-BCI and tDCS intervention in chronic subcortical stroke patients with unilateral upper limb disability. Nineteen patients were randomized into tDCS and sham-tDCS groups. Diffusion and perfusion MRI, and transcranial magnetic stimulation were used to study structural connectivity, cerebral blood flow (CBF), and corticospinal excitability, respectively, before and 4 weeks after the 2-week intervention. After quality control, thirteen subjects were included in the CBF analysis. Eleven healthy controls underwent 2 sessions of MRI for reproducibility study. Whereas motor performance showed comparable improvement, long-lasting neuroplasticity can only be detected in the tDCS group, where white matter integrity in the ipsilesional corticospinal tract and bilateral corpus callosum was increased but sensorimotor CBF was decreased, particularly in the ipsilesional side. CBF change in the bilateral parietal cortices also correlated with motor function improvement, consistent with the increased white matter integrity in the corpus callosum connecting these regions, suggesting an involvement of interhemispheric interaction. The preliminary results indicate that tDCS may facilitate neuroplasticity and suggest the potential for refining rehabilitation strategies for stroke patients.

The role of the ipsilesional side in the rehabilitation of post-stroke subjects

Most stroke lesions occur in the middle cerebral artery territory, presenting a high probability of damage of pathways with predominant ipsilesional disposition, mainly related to postural control. Despite the high probability of bilateral postural control dysfunction based on neuroanatomical fundaments, both research and clinical rehabilitation involving stroke subjects have been focused on contralesional side (also named affected side) impairments, while ipsilesional side (also named non-affected side) impairments have been attributed to an adaptive strategy. This paper aims to present a critical understanding about the state-of-the-art that sustains the hypothesis that stroke subjects with middle cerebral artery territory lesion at the subcortical level show an atypical behaviour in the ipsilateral side associated with the lesion itself and the possible implications.

Abstract WP263: Feasibility and Utility Of EEG for Estimating Infarct Volume During ER Assessment of Suspected Acute Stroke--A Pilot Study

Introduction: Endovascular therapy (EVT) improves outcomes in the setting of acute ischemic stroke (AIS) in a time-dependent manner, highlighting the need for improved methods to rapidly identify eligible patients, particularly in the pre-hospital setting. Current pre-hospital assessments are imprecise for this goal. Pre-hospital measurement of brain injury via EEG might provide additional useful diagnostic information regarding EVT eligibility. As a first step, the current study examined (1) feasibility of obtaining EEG early during ER assessment of patients with suspected AIS, and (2) EEG metrics predicting infarct volume. Methods: In subjects transported to the UC Irvine Medical Center for suspected AIS, a 3 min dense-array resting EEG was obtained during ED assessment. Results: EEG was acquired in 25 subjects (mean age 65 yr), 12 of whom were discharged with a diagnosis of radiologically confirmed AIS and 13 of whom were discharged with a non-stroke diagnosis. Median time from ED arrival to EEG = 114 min (and as early as 32 min after arrival), and time from last known well to EEG = 333 min. EEG was acquired in 24 subjects, with data lost due to human error in 1 subject. Among patients with AIS, median NIHSS score = 4 (range 0-19) and median infarct volume = 12 cc (range 0.3- 83). Infarct volume was found to correlate inversely with power in the low beta (13-19Hz) frequency range, bilaterally: larger infarcts were associated with reduced beta power in the leads over motor cortex (C3, C4) on the ipsilesional side (rho = -0.57, p=0.03) and on the contralesional side (rho = -0.60, p=0.02). Conclusions: The current findings support the potential of rapid EEG methods to identify patients with large infarcts who may be ideal candidates for EVT. Future studies will examine how well current findings extend to the pre-hospital setting, and how specific these EEG findings are for patients eligible for EVT.

Magnetic resonance imaging of the functional anatomy of the superior oblique muscle in patients with primary superior oblique overaction

PurposeTo quantitatively determine the size and contractility of the superior oblique (SO) muscle in primary SO overaction (PSOOA).Patients and methodsA prospective, observational study was conducted on 12 patients with PSOOA, and 10 healthy, orthotropic subjects. Sets of contiguous, 2 mm slice thickness, quasi-coronal magnetic resonance imaging were obtained during different gazes, giving pixel resolution of 0.391 mm. Cross-sectional areas of the SO muscles were determined in primary position, supraduction, and infraduction to evaluate size and contractility. The cross-sectional areas of SO muscle were compared with those of controls in the primary position to detect hypertrophy or atrophy and changes in contractility could be detected during the vertical gaze. All statistical calculations were performed using PROC MIXED (SAS 9.4).ResultsThere was no difference between the ipsilesional (affected eye), contralesional (unaffected eye), and normal SO muscle cross-sections: 0.176±0.018 cm2, 0.175±0.005 cm2, and 0.173±0.015 cm2, respectively (P=0.82). The maximum contractility of SO muscle on the ipsilesional (affected) side was 0.097±0.024 cm2, and was different than on the contralesional (unaffected) side: 0.067±0.015 cm2 and in control subjects: 0.063±0.018 cm2 (P=0.0002).ConclusionsIn PSOOA, the ipsilesional SO is more contractile than the contralesional SO muscle and different than in controls, with no difference in SO muscle size in primary position, which suggests that excessive innervation rather than muscle hypertrophy underlies PSOOA.

Nucleus prepositus hypoglossi lesions produce a unique ocular motor syndrome

To describe the ocular motor abnormalities in 9 patients with a lesion involving the nucleus prepositus hypoglossi (NPH), a key constituent of a vestibular-cerebellar-brainstem neural network that ensures that the eyes are held steady in all positions of gaze. We recorded eye movements, including the vestibulo-ocular reflex during head impulses, in patients with vertigo and a lesion involving the NPH. Our patients showed an ipsilesional-beating spontaneous nystagmus, horizontal gaze-evoked nystagmus more intense on looking toward the ipsilesional side, impaired pursuit more to the ipsilesional side, central patterns of head-shaking nystagmus, contralateral eye deviation, and decreased vestibulo-ocular reflex gain during contralesionally directed head impulses. We attribute these findings to an imbalance in the NPH-inferior olive-flocculus-vestibular nucleus loop, and the ocular motor abnormalities provide a new brainstem localization for patients with acute vertigo.

When Does Return of Voluntary Finger Extension Occur Post-Stroke? A Prospective Cohort Study.

ObjectivesPatients without voluntary finger extension early post-stroke are suggested to have a poor prognosis for regaining upper limb capacity at 6 months. Despite this poor prognosis, a number of patients do regain upper limb capacity. We aimed to determine the time window for return of voluntary finger extension during motor recovery and identify clinical characteristics of patients who, despite an initially poor prognosis, show upper limb capacity at 6 months post-stroke.MethodsSurvival analysis was used to assess the time window for return of voluntary finger extension (Fugl-Meyer Assessment hand sub item finger extension≥1). A cut-off of ≥10 points on the Action Research Arm Test was used to define return of some upper limb capacity (i.e. ability to pick up a small object). Probabilities for regaining upper limb capacity at 6 months post-stroke were determined with multivariable logistic regression analysis using patient characteristics.Results45 of the 100 patients without voluntary finger extension at 8 ± 4 days post-stroke achieved an Action Research Arm Test score of ≥10 points at 6 months. The median time for regaining voluntary finger extension for these recoverers was 4 weeks (lower and upper percentile respectively 2 and 8 weeks). The median time to return of VFE was not reached for the whole group (N = 100). Patients who had moderate to good lower limb function (Motricity Index leg≥35 points), no visuospatial neglect (single-letter cancellation test asymmetry between the contralesional and ipsilesional sides of <2 omissions) and sufficient somatosensory function (Erasmus MC modified Nottingham Sensory Assessment≥33 points) had a 0.94 probability of regaining upper limb capacity at 6 months post-stroke.ConclusionsWe recommend weekly monitoring of voluntary finger extension within the first 4 weeks post-stroke and preferably up to 8 weeks. Patients with paresis mainly restricted to the upper limb, no visuospatial neglect and sufficient somatosensory function are likely to show at least some return of upper limb capacity at 6 months post-stroke.