Prognostic value of median and tibial somatosensory evoked potentials in acute stroke

Predictors of manual dexterity at 3 and 6 months after stroke: integration of clinical, neurophysiological, and neuroimaging factors

This retrospective study aimed to predict dexterity at 3 and 6 months post-stroke by integrating clinical, neurophysiological, and neuroimaging factors. We included 126 patients with first-ever, unilateral, and supratentorial stroke. Demographic, stroke characteristics, and initial clinical assessment variables [Mini-mental state examination and Fugl-Meyer Assessment Upper Extremity (FMA-UE)] were evaluated 2 weeks after stroke. Dexterity, measured using the Manual Function Test (MFT) hand subscore, was the primary outcome. The neurophysiological variables, upper limb somatosensory evoked potential (SEP) and motor evoked potential (MEP), were assessed 2 weeks post-stroke. The neuroimaging variable, fractional anisotropy (FA) of the corticospinal tract (CST), was assessed 3 weeks post-stroke. Multiple regression analysis revealed significant predictors for improved dexterity at 3 and 6 months post-stroke, including younger age, higher FMA-UE score, presence of waveforms in the SEP and MEP, and higher FA values in the CST (adjusted R 2  = 0.776, P  < 0.001 at 3 months; adjusted R 2  = 0.668, P  < 0.001 at 6 months; where MEP, SEP, and FA accounted together for an additional 0.079 and 0.166 of variance beyond age and FMA-UE, respectively). Subgroup analysis was conducted by categorizing the participants based on their initial hand function: those with no hand function (MFT hand subscore = 0) (N = 60) and those with a score >0 (N = 51). Initial FMA-UE was a primary predictive factor regardless of the time point or initial severity, whereas the presence of MEP was a significant predictor only in the group with no initial hand dexterity.

The locations of stroke lesions next to the posterior internal capsule may predict the recovery of the related proprioceptive deficits

Background

Somatosensory deficits after stroke correlate with functional disabilities and impact everyday-life. In particular, the interaction of proprioception and motor dysfunctions affects the recovery. While corticospinal tract (CST) damage is linked to poor motor outcome, much less is known on proprioceptive recovery. Identifying a predictor for such a recovery could help to gain insights in the complex functional recovery processes thereby reshaping rehabilitation strategies.

Methods

50 patients with subacute stroke were tested before and after neurological rehabilitation. Proprioceptive and motor impairments were quantified with three clinical assessments and four hand movement and proprioception measures using a robotic device. Somatosensory evoked potentials (SSEP) to median nerve stimulation and structural imaging data (MRI) were also collected. Voxel-based lesion-symptom mapping (VLSM) along with a region of interest (ROI) analysis were performed for the corticospinal tract (CST) and for cortical areas.

Results

Before rehabilitation, the VLSM revealed lesion correlates for all clinical and three robotic measures. The identified voxels were located in the white matter within or near the CST. These regions associated with proprioception were located posterior compared to those associated with motor performance. After rehabilitation the patients showed an improvement of all clinical and three robotic assessments. Improvement in the box and block test was associated with an area in anterior CST. Poor recovery of proprioception was correlated with a high lesion load in fibers towards primary sensorymotor cortex (S1 and M1 tract). Patients with loss of SSEP showed higher lesion loads in these tracts and somewhat poorer recovery of proprioception. The VSLM analysis for SSEP loss revealed a region within and dorsal of internal capsule next to the posterior part of CST, the posterior part of insula and the rolandic operculum.

Conclusion

Lesions dorsal to internal capsule next to the posterior CST were associated with proprioceptive deficits and may have predictive value. Higher lesion load was correlated with poorer restoration of proprioceptive function. Furthermore, patients with SSEP loss trended towards poor recovery of proprioception, the corresponding lesions were also located in the same location. These findings suggest that structural imaging of the internal capsule and CST could serve as a recovery predictor of proprioceptive function.

Study of Short Latency Somatosensory and Brain Stem Auditory Evoked Potentials Patients with Acute Ischemic Stroke Involving Middle Cerebral Artery Territory

Background  The precise timings of evoked potentials in evaluating the functional outcome of stroke have remained indistinct. Few studies in the Indian context have studied the outcome of early prognosis of stroke utilizing evoked potentials.

Objective  The aim of this study was to determine somatosensory evoked potentials (SSEPs) and brain stem auditory evoked potentials (BAEPs), their timing and abnormalities in acute ischemic stroke involving the middle cerebral artery (MCA) territory and to correlate SSEP and BAEP with the functional outcome (National Institutes of Health Stroke Scale (NIHSS), modified Rankin scale (mRS) and Barthel’s index) at 3 months.

Methods  MCA territory involved acute ischemic stroke patients ( n = 30) presenting consecutively to the hospital within 3 days of symptoms onset were included. Details about clinical symptoms, neurological examination, treatment, NIHSS score, mRS scores were collected at the time of admission. All patients underwent imaging of the brain and were subjected to SSEP and BAEP on two occasions, first at 1 to 3 days and second at 4 to 7 days from the onset of stroke. At 3 months of follow-up, NIHSS, mRS, and Barthel’s index were recorded.

Results  P37 and N20 amplitude had a strong negative correlation (at 1–3 and 4–7 days) with NIHSS at admission, NIHSS at 3 months, mRS at admission, and mRS at 3 months and a significant positive correlation with Barthel’s index ( p  < 0.0001). BAEP wave V had a negative correlation (at 1–3 and 4–7 days) with NIHSS at admission, NIHSS at 3 months, mRS at admission, and mRS at 3 months and a positive correlation with Barthel’s index ( p < 0.0001).

Conclusion  SSEP abnormalities recorded on days 4 to 7 from onset of stroke are more significant than those recorded within 1 to 3 days of onset of stroke; hence, the timing of 4 to 7 days after stroke onset can be considered as better for predicting functional outcome.

A precision neurorehabilitation using SSEP for early detection of sensory deficit and restoration of the motor recovery in balance, gait and activities of daily living in acute stroke

BACKGROUND:

Impaired sensory in acute stroke patients results in dynamic balance, gait and activities of daily living (ADL) impairment.

OBJECTIVE:

The aim of present study was to examine the correlation between somatosensory-evoked potential (SSEP) parameters and motor recovery in balance, gait and ADL performance in hemiparetic stroke survivors.

METHODS:

One hundred and one participants with hemiparetic stroke (43 males, 58 females; mean age, 6538 ± 1222 years; post-stroke duration, 199 ± 0.74 month) participated in this study. The Electro Synergy system (Viasys Healthcare; San Diego, CA, USA) was applied to measure SSEP measurement. The 101 stroke survivors were divided into three groups consistent with their SSEP results: sensory normal group; sensory impaired group; sensory absent group. All the subject participated the inpatient rehabilitation intervention for 4 weeks. Analyses of variance (ANOVA) were used to verify the group difference among the three groups after the treatment.

RESULTS:

ANOVA revealed the significant difference (p< 0.01). The Scheffe test demonstrated that the sensory normal group showed greater increasement in Modified Barthel Index (MBI), Fugl-Myer Assessment (FMA), Trunk Impairment Scale (TIS), Berg Balance Scale (BBS) and Functional Ambulation Category (FAC) scores than the sensory impaired and absent group (p< 0.05).

CONCLUSIONS:

Our research provides therapeutic evidence that correlation of somatosensory functions on motor recovery, balance, gait, and ADL in patients with hemiplegic stroke.

Multimodal Long-Term Predictors of Outcome in Out of Hospital Cardiac Arrest Patients Treated with Targeted Temperature Management at 36 °C

Introduction: Early prediction of long-term outcomes in patients resuscitated after cardiac arrest (CA) is still challenging. Guidelines suggested a multimodal approach combining multiple predictors. We evaluated whether the combination of the electroencephalography (EEG) reactivity, somatosensory evoked potentials (SSEPs) cortical complex and Gray to White matter ratio (GWR) on brain computed tomography (CT) at different temperatures could predict survival and good outcome at hospital discharge and six months after the event. Methods: We performed a retrospective cohort study including consecutive adult, non-traumatic patients resuscitated from out-of-hospital CA who remained comatose on admission to our intensive care unit from 2013 to 2017. We acquired SSEPs and EEGs during the treatment at 36 °C and after rewarming at 37 °C, Gray to white matter ratio (GWR) was calculated on the brain computed tomography scan performed within six hours of the hospital admission. We primarily hypothesized that SSEP was associated with favor-able functional outcome at distance and secondarily that SSEP provides independent information from EEG and CT. Outcomes were evaluated using the Cerebral Performance Category (CPC) scale at six months from discharge. Results: Of 171 resuscitated patients, 75 were excluded due to missing data or uninterpretable neurophysiological findings. EEG reactivity at 37 °C has been shown the best single predictor of good out-come (AUC 0.803) while N20P25 was the best single predictor for survival at each time point. (AUC 0.775 at discharge and AUC 0.747 at six months follow up). The predictive value of a model including EEG reactivity, average GWR, and SSEP N20P25 amplitude was superior (AUC 0.841 for survival and 0.920 for good out-come) to any combination of two tests or any single test. Conclusions: Our study, in which life-sustaining treatments were never suspended, suggests SSEP cortical complex N20P25, after normothermia and off sedation, is a reliable predictor for survival at any time. When SSEP cortical complex N20P25 is added into a model with GWR average and EEG reactivity, the predictivity for good outcome and survival at distance is superior than each single test alone.

Robot-assisted gait training effectively improved lateropulsion in subacute stroke patients: a single-blinded randomized controlled trial

BACKGROUND

Some stroke patients are known to use nonparetic extremities to push toward the paretic side, a movement known as lateropulsion. Lateropulsion impairs postural balance and interferes with rehabilitation.

AIM

The aim of the present study was to investigate the effect of robot-assisted gait training (RAGT) on recovery from lateropulsion compared with conventional physical therapy (CPT).

DESIGN

This was a single-blinded, randomized controlled trial.

SETTING

Participants were recruited from a rehabilitation department of a tertiary hospital.

POPULATION

Patients diagnosed with lateropulsion after a stroke.

METHODS

Thirty-six subacute stroke patients with lateropulsion were recruited. RAGT was performed in the experimental group (N.=18), and CPT was performed in the control group (N.=18). The participants received treatment for 3 weeks, 30 minutes per day, 5 days per week. Outcomes were assessed before the intervention (T0), immediately after the intervention (T1), and 4 weeks after the intervention (T2). The Burke Lateropulsion Scale (BLS) was evaluated as a primary outcome to assess the severity of lateropulsion. The secondary outcome measures were the Berg Balance Scale (BBS), the Postural Assessment Scale for Stroke (PASS), and Somatosensory Evoked Potentials (SSEP).

RESULTS

After intervention, the experimental group showed greater improvement in the BLS score at T1 (experimental group: Δ=-1.9, control group: Δ=-1.1, P=0.032) and T2 (experimental group: Δ=-2.8, control group: Δ=-6.5, P<0.001) than the control group. In addition, the BBS was significantly improved in the experimental group at T1 (experimental group: Δ=+7.1, control group: Δ=+1.9, P<0.001) and T2 (experimental group: Δ=+13.0, control group: Δ=+6.1, P<0.001). There were significant between-group differences in the PASS at T1 (experimental group: Δ=+3.2, control group: Δ=+1.6, P=0.014) and T2 (experimental group: Δ=+8.8, control group: Δ=+4.3, P<0.001).

CONCLUSIONS

RAGT ameliorated lateropulsion and balance function more effectively than CPT in subacute stroke patients.

CLINICAL REHABILITATION IMPACT

Early RAGT may be recommended for patients with lateropulsion after stroke.

Effect of rehabilitation on the somatosensory evoked potentials and gait performance of hemiparetic stroke patients

BACKGROUND:

Gait performance of stroke patients is affected by impaired sensory ability. The purpose of the present study was to determine the relationship between somatosensory-evoked potential (SSEP) parameters and gait performance in hemiparetic stroke patients.

METHODS:

A convenience sample of 17 hemiparetic stroke patients (mean age 60.11 ± 8.83 years; 10 women; right hemiplegia: 10, left hemiplegia: 7) were recruited for the present study. The Electro Synergy system (Viasys Healthcare; San Diego, CA, USA) was used for SSEP evaluation. The 17 patients were assigned to two groups according to their SSEP results as follows: 8 patients to the normal response group and 9 patients to the abnormal group. All the participants underwent the same rehabilitation exercise programs during 4 weeks, followed by clinical evaluation. A mixed-design analysis of a variance model was used to test for differences in timed up-and-go (TUG) test and 10-meter walking test (10MWT) scores between the two independent groups while the participants were subjected to repeated measures (pretest and posttest).

RESULTS:

Analysis of variance revealed the main time effect (p< 0.05) and group by time interaction effect (p< 0.05). The post hoc test result confirmed that the normal sensory group showed greater improvement in TUG test and 10MWT scores than the abnormal sensory group (p< 0.05). The TUG test and 10MWT scores in the posttest were greater in the normal sensory group than in the abnormal sensory group.

CONCLUSIONS:

The present study demonstrated the importance of the clinical contribution of the baseline sensory function of individuals with hemiparetic stroke to their gait performance and recovery after stroke rehabilitation. As anticipated, the individuals who had intact or spared sensory function showed greater improvements in gait speed and performance measures than those who had impaired sensory function.

A systematic review investigating the relationship of electroencephalography and magnetoencephalography measurements with sensorimotor upper limb impairments after stroke

BACKGROUND

Predicting sensorimotor upper limb outcome receives continued attention in stroke. Neurophysiological measures by electroencephalography (EEG) and magnetoencephalography (MEG) could increase the accuracy of predicting sensorimotor upper limb recovery.

NEW METHOD

The aim of this systematic review was to summarize the current evidence for EEG/MEG-based measures to index neural activity after stroke and the relationship between abnormal neural activity and sensorimotor upper limb impairment. Relevant papers from databases EMBASE, CINHAL, MEDLINE and pubMED were identified. Methodological quality of selected studies was assessed with the Modified Downs and Black form. Data collected was reported descriptively.

RESULTS

Seventeen papers were included; 13 used EEG and 4 used MEG applications. Findings showed that: (a) the presence of somatosensory evoked potentials in the acute stage are related to better outcome of upper limb motor impairment from 10 weeks to 6 months post-stroke; (b) an interhemispheric imbalance of cortical oscillatory signals associated with upper limb impairment; and (c) predictive models including beta oscillatory cortical signal factors with corticospinal integrity and clinical measures could enhance upper limb motor prognosis.

COMPARING WITH EXISTING METHOD

The combination of neurological biomarkers with clinical measures results in higher statistical power than using neurological biomarkers alone when predicting motor recovery in stroke.

CONCLUSIONS

Alterations in neural activity by means of EEG and MEG are demonstrated from the early post-stroke stage onwards, and related to sensorimotor upper limb impairment. Future work exploring cortical oscillatory signals in the acute stage could provide further insight about prediction of upper limb sensorimotor recovery.

Integrated treatment modality of cathodal-transcranial direct current stimulation with peripheral sensory stimulation affords neuroprotection in a rat stroke model

Cathodal-transcranial direct current stimulation induces therapeutic effects in animal ischemia models by preventing the expansion of ischemic injury during the hyperacute phase of ischemia. However, its efficacy is limited by an accompanying decrease in cerebral blood flow. On the other hand, peripheral sensory stimulation can increase blood flow to specific brain areas resulting in rescue of neurovascular functions from ischemic damage. Therefore, the two modalities appear to complement each other to form an integrated treatment modality. Our results showed that hemodynamics was improved in a photothrombotic ischemia model, as cerebral blood volume and hemoglobin oxygen saturation ([Formula: see text]) recovered to 71% and 76% of the baseline values, respectively. Furthermore, neural activities, including somatosensory-evoked potentials (110% increase), the alpha-to-delta ratio (27% increase), and the [Formula: see text] ratio (27% decrease), were also restored. Infarct volume was reduced by 50% with a 2-fold preservation in the number of neurons and a 6-fold reduction in the number of active microglia in the infarct region compared with the untreated group. Grip strength was also better preserved (28% higher) compared with the untreated group. Overall, this nonpharmacological, nonintrusive approach could be prospectively developed into a clinical treatment modality.

Continuous EEG monitoring in the intensive care unit

The purpose and indications for continuous electroencephalography monitoring (CEEG) in intensive care unit (ICU) patients include seizure detection, monitoring the effects of treatment (including depth of sedation), grading and classification of EEG abnormalities, ischemia detection and prognostication. Practical considerations of ICU CEEG include: choice of montages (patterns of electrode placement and connections), EEG electrodes, recognition of artifacts, and the use of automated or computerized analysis. These aspects are reviewed, along with an identifcation of current advances and challenges for the future of CEEG in the ICU.

Tibial somatosensory evoked potential can prognosticate for ambulatory function in subacute hemiplegic stroke

Early prediction of expected recovery in stroke can help in planning appropriate medical and rehabilitation interventions. Recovery of ambulation is one of the essential endpoints in stroke rehabilitation. However, the correlation of somatosensory evoked potentials (SSEP) with clinical parameters and their predictive significance are not clearly defined. We aimed to examine the association between tibial nerve SSEP and ambulatory outcomes in subacute hemiplegic stroke patients. We reviewed medical records for hemiplegic patients with first-ever stroke who received inpatient rehabilitation from January 2009 to May 2013. We excluded patients with diabetes mellitus, quadriplegia, bilateral lesions, brainstem lesions, those aged over 80 years, and those with severe musculoskeletal problems. Tibial nerve SSEP were performed when they were transferred to the rehabilitation department. SSEP findings were divided into three groups; normal, abnormal and absent response. Berg balance scale and functional ambulation category (FAC) at discharge were compared with initial tibial SSEP findings using one-way analysis of variance. Thirty-one hemiplegic patients were included. Berg balance scale and FAC were significantly different according to the SSEP (P<0.001). Post hoc analysis showed a significant difference between normal and absent response in Berg balance scale (P<0.001) and FAC (P<0.001), and between abnormal and absent response in Berg balance scale (P=0.012) and FAC (P=0.019). Functional outcomes of the normal response group were better than the abnormal response group, but there was no statistical significance. These findings suggest that initial tibial nerve SSEP may be a useful biomarker for prognosticating functional outcomes in hemiplegic patients.

Prognostic value of somatosensory evoked potentials, neuron-specific enolase, and S100 for short-term outcome in ischemic stroke

To predict short-term outcome in acute ischemic stroke, we analyzed somatosensory evoked potentials (SEP) and biochemical parameters [neuron-specific enolase (NSE) and S100 protein] in a prospective study with serial measurement. In 31 patients with 1st middle cerebral artery infarction, serum NSE and S100 protein were measured daily between days 1 and 6 poststroke. The N20 and N70 components of the SEP (SEP20 and SEP70) were determined on days 1 and 6. SEP and biochemical markers in stroke patients were compared with a control group. Short-term outcome was assessed by the modified Rankin Scale (mRS) at days 7-10 and was dichotomized between good (mRS 0-2) and poor (mRS ≥3) outcome. Specificity and positive predictive value (PPV) were high at day 1 for SEP (SEP20: 100% for both; SEP70: 93 and 88%, respectively) compared with lower values for NSE (67 and 50%) and S100 (23 and 57%). In contrast, S100 showed the highest sensitivity at day 1 with 77% compared with a relatively low sensitivity of NSE (31%) and SEP (SEP20: 35%, SEP70: 47%). The biochemical markers showed an improving sensitivity over time with best values (>90%) between days 3 and 4 at the expense of a lower specificity. Specificity and PPV of SEP on day 6 was still 100% with sensitivity increasing up to 53% (SEP20) and 60% (SEP70). SEP could early differentiate between good and poor outcome and reliably predict poor outcome. Since biochemical markers and SEP complement each other in the prognosis of stroke, a combined application of these markers seems promising.

May clinical neurophysiology help to predict the recovery of neurological early rehabilitation patients?

BACKGROUND

So far, the role of clinical neurophysiology in the prediction of outcome from neurological and neurosurgical early rehabilitation is unclear.

METHODS

Clinical and neurophysiological data of a large sample of 803 early rehabilitation cases of the BDH-Clinic Hessisch Oldendorf in Northern Germany have been carefully reviewed. Most patients (43.5%) were transferred to rehabilitation after stroke, mean age was 66.6 (15.5) years. Median somatosensory (SEP), auditory (AEP) and visual evoked potentials (VEP) along with EEG recordings took place within the first two weeks after admission. Length of stay (LOS) in early rehabilitation was 38.3 (37.2) days.

RESULTS

Absence of SEP on one or both sides was associated with poor outcome, χ2 = 12.98 (p = 0.005); only 12.5% had a good outcome (defined as Barthel index, BI ≥50) when SEP were missing on both sides. In AEP, significantly longer bilateral latencies III were observed in the poor outcome group (p < 0.05). Flash VEP showed that patients in the poor outcome group had a significantly longer latency III on both sides (p < 0.05). The longer latency III, the smaller BI changes (BI discharge minus admission) were observed (latency III right r = -0.145, p < 0.01; left r = -0.206, p < 0.001). While about half of the patients with alpha EEG activity belonged to the good outcome group (80/159, 50.3%), only 39/125 (31.2%) with theta and 5/41 (12.2%) with delta rhythm had a favourable outcome, χ2 = 24.2, p < 0.001.

CONCLUSIONS

Results from this study suggest that loss of median SEP, prolongation of wave III in AEP and flash-VEP as well as theta or delta rhythms in EEG are associated with poor outcome from neurological early rehabilitation. Further studies on this topic are strongly encouraged.

Association Between Evoked Potentials and Balance Recovery in Subacute Hemiparetic Stroke Patients

Objective

To investigate the association between baseline motor evoked potential (MEP) and somatosensory evoked potential (SSEP) responses in the lower extremities and balance recovery in subacute hemiparetic stroke patients.

Methods

MEPs and SSEPs were evaluated in 20 subacute hemiparetic stroke patients before rehabilitation. Balance (static posturography and Berg Balance Scale [BBS]), motor function (Fugl-Meyer Assessment [FMA]) and the ability to perform activities of daily living (Modified Barthel Index [MBI]) were evaluated before rehabilitation and after four-weeks of rehabilitation. Posturography outcomes were weight distribution indices (WDI) expressed as surface area (WDI-Sa) and pressure (WDI-Pr), and stability indices expressed as surface area (SI-Sa) and length (SI-L). In addition, all parameters were evaluated during eyes open (EO) and eyes closed (EC) conditions.

Results

The MEP (+) group showed significant improvements in balance except WDI-Sa (EC), FMA, and MBI, while the MEP (-) group showed significant improvements in the BBS, FMA, and MBI after rehabilitation. The SSEP (+) group showed significant improvements in balance except SI-Sa (EO), FMA, and MBI, while the SSEPs (-) group showed significant improvements in the BBS, MBI after rehabilitation. The changes in the SI-Sa (EO), SI-L (EO), total MBI, and several detailed MBI subscales in the MEP (+) group after rehabilitation were significantly larger than those in the MEP (-) group.

Conclusion

Our findings suggest that initial assessments of MEPs and SSEPs might be beneficial when predicting balance recovery in subacute hemiparetic stroke patients.

Neuroprotective effects of ginsenoside Rg1-induced neural stem cell transplantation on hypoxic-ischemic encephalopathy

Ginsenoside Rg1 is the major pharmacologically active component of ginseng, and is reported to have various therapeutic actions. To determine whether it induces the differentiation of neural stem cells, and whether neural stem cell transplantation after induction has therapeutic effects on hypoxic-ischemic encephalopathy, we cultured neural stem cells in 10–80 μM ginsenoside Rg1. Immunohistochemistry revealed that of the concentrations tested, 20 mM ginsenoside Rg1 had the greatest differentiation-inducing effect and was the concentration used for subsequent experiments. Whole-cell patch clamp showed that neural stem cells induced by 20 μM ginsenoside Rg1 were more mature than non-induced cells. We then established neonatal rat models of hypoxic-ischemic encephalopathy using the suture method, and ginsenoside Rg1-induced neural stem cells were transplanted via intracerebroventricular injection. These tests confirmed that neural stem cells induced by ginsenoside had fewer pathological lesions and had a significantly better behavioral capacity than model rats that received saline. Transplanted neural stem cells expressed neuron-specific enolase, and were mainly distributed in the hippocampus and cerebral cortex. The present data suggest that ginsenoside Rg1-induced neural stem cells can promote the partial recovery of complicated brain functions in models of hypoxic-ischemic encephalopathy.

Outcome of Intensive Care Unit-Dependent, Tracheotomized Patients with Cerebrovascular Diseases

BACKGROUND

Outcome studies in intensive care unit -dependent, tracheotomized, and mechanical ventilated patients with cerebrovascular disease (CVD) are scarce.

METHODS

In a retrospective approach, we analyzed the outcome of 143 patients with ischemic stroke (IS), primary intracerebral hemorrhage (PICH), and subarachnoid hemorrhage (SAH). To measure the potential benefit of in-patient rehabilitation, we used the Functional Independence Measure (FIM). In addition, weaning and rehabilitation duration, duration of mechanical ventilation (MV) in the acute care hospital (preweaning), and mortality rates were assessed.

RESULTS

Approximately 50% of all patients were transferred home. These patients were fully independent or under nursing support. We found no differences regarding weaning and rehabilitation durations, or FIM scores in between each entity. Log-regression analyses showed that every day on MV generates a 3.2% reduction of the possibility to achieve a beneficial outcome (FIM ≥ 50 points [only moderate assistance necessary]), whereas every day in-patient rehabilitation without MV increases the chance for favorable outcome by 1.9%. Mortality rates were 5% for IS and 10% for PICH and SAH, respectively.

CONCLUSIONS

This study shows that even severely affected, tracheotomized patients with CVD benefit from early in-patient rehabilitation, irrespective of the etiology of vascular brain injury. Mortality rates of early rehabilitation in CVD are low. Until no validated outcome predictors are available, all efforts should be undertaken to enable in-patient rehabilitation, even in severe cases of CVD to improve outcome and to prevent accommodation in long-time-care facilities.

The value of the ucN13-P15 interpeak latency predicted acute posterior circulation ischemia and the chronic outcome

OBJECTIVE

To determine the sensitivity and specificity of the ucN13-P15 (CV2-Fz) and IcN13-P15 (CV7-Fz) interpeak latencies when used to predict acute posterior circulation ischemia.

METHODS

A total of 426 consecutive patients who were hospitalized within 3 days of the onset of stroke were prospectively enrolled in the study. Of these patients, 110 had infarct lesions in the posterior circulation territory. The ucN13-P15 and IcN13-P15 interpeak latencies on admission were assessed, and the chronic outcome was assessed at 3 months.

RESULTS

The ucN13-P15 and IcN13-P15 interpeak latencies (both P < 0.001) were prolonged in patients with posterior circulation ischemia than in those with anterior circulation ischemia. The optimal cutoff score of the baseline ucN13-P15 IPL (≥ 3.35 milliseconds) had a sensitivity of 76.8% and a specificity of 79.9%. The IcN13-P15 IPL (≥ 4.225 milliseconds) had a sensitivity of 56.1% and a specificity of 93.2%.

CONCLUSIONS

The ucN13-P15 interpeak latency must be appraised in light of its diagnostic value in acute posterior circulation ischemia. However, the ucN13-P15 interpeak latency was not independently predictive of a favorable outcome.

Whole-scalp EEG mapping of somatosensory evoked potentials in macaque monkeys

High-density scalp EEG recordings are widely used to study whole-brain neuronal networks in humans non-invasively. Here, we validate EEG mapping of somatosensory evoked potentials (SSEPs) in macaque monkeys (Macaca fascicularis) for the long-term investigation of large-scale neuronal networks and their reorganisation after lesions requiring a craniotomy. SSEPs were acquired from 33 scalp electrodes in five adult anaesthetized animals after electrical median or tibial nerve stimulation. SSEP scalp potential maps were identified by cluster analysis and identified in individual recordings. A distributed, linear inverse solution was used to estimate the intracortical sources of the scalp potentials. SSEPs were characterised by a sequence of components with unique scalp topographies. Source analysis confirmed that median nerve SSEP component maps were in accordance with the somatotopic organisation of the sensorimotor cortex. Most importantly, SSEP recordings were stable both intra- and interindividually. We aim to apply this method to the study of recovery and reorganisation of large-scale neuronal networks following a focal cortical lesion requiring a craniotomy. As a prerequisite, the present study demonstrated that a 300-mm² unilateral craniotomy over the sensorimotor cortex necessary to induce a cortical lesion, followed by bone flap repositioning, suture and gap plugging with calcium phosphate cement, did not induce major distortions of the SSEPs. In conclusion, SSEPs can be successfully and reproducibly recorded from high-density EEG caps in macaque monkeys before and after a craniotomy, opening new possibilities for the long-term follow-up of the cortical reorganisation of large-scale networks in macaque monkeys after a cortical lesion.

Predictors of upper limb recovery after stroke: a systematic review and meta-analysis

OBJECTIVE

To systematically review and summarize the current available literature on prognostic variables relating to upper limb recovery following stroke. To identify which, if any variables predict upper limb recovery following stroke.

DATA SOURCES

We completed searches in MEDLINE, EMBASE, AMED, CINAHL and Cochrane CENTRAL databases. Searches were completed in November 2010.

REVIEW METHODS

Studies were included if predictor variables were measured at baseline and linked to an outcome of upper limb recovery at a future time point. Exclusion criteria included predictor variables relating to response to treatment and outcome measurements of very specific upper limb impairments such as spasticity or pain. Two independent reviewers completed data extraction and assessed study quality.

RESULTS

Fifty-eight studies met the inclusion criteria. Predictor variables which have been considered within these studies include; age, sex, lesion site, initial motor impairment, motor-evoked potentials and somatosensory-evoked potentials. Initial measures of upper limb impairment and function were found to be the most significant predictors of upper limb recovery; odds ratio 14.84 (95% confidence intervals (CI) 9.08-24.25) and 38.62 (95% CI 8.40-177.53), respectively.

CONCLUSIONS

Interpretation of these results is complicated by methodological factors including variations in study populations, upper limb motor outcome scales, timing of baseline and outcome assessments and predictors selected. The most important predictive factors for upper limb recovery following stroke appears to the initial severity of motor impairment or function.

Topographic MN-SSEPs (N18, N20 and N30) might characterize underlying CNS involvements in representative types of cerebral palsy

This study is aimed at constructing the neurophysiological basis for determining the characteristic features of cerebral motor disturbance in representative cerebral palsy (CP) types using topographical S-SEPs technology. Median-nerve stimulated S-SEPs (MN-SSEPs) were examined for 23 patients with four representative types of cerebral palsy: 6 athetotic (including 3 patients due to hypoxic-ischemic encephalopathy (HIE) and 3 to kernicterus), 7 hemiplegic, 5 diplegic and 5 tetraplegic types, and 13 normal controls. In HIE group of athetotic CP, frontal N30 specifically showed severe amplitude reduction or abolishment. In hemiplegic CP, both N20 and N30 on the affected cerebral side tended either to disappear or to be normally evoked at the same time, and their mean amplitudes declined severely. In diplegic CP, the amplitudes of subcortical N18 and parietal N20 were not small but significantly enlarged. N30 amplitude stayed within normal. The reason for this unexpected enlargement of N18 and N20 is unclear, but may be partly due to premature birth which caused abnormally abundant dendritic spine due to absence from perinatal normal spine elimination in the brainstem. In several quadriplegic patients, both N20 and N30 disappeared. The mean amplitude of N30 severely decreased. In conclusion, topographical results of N18, N20 and N30 may basically suggest the underlying involvement of nervous structures in CP according to their representative type.