Corticospinal inhibition investigated in relation to upper extremity motor function in cervical spinal cord injury

OBJECTIVE

Corticospinal inhibitory mechanisms are relevant to functional recovery but remain poorly understood after spinal cord injury (SCI). Post-injury characteristics of contralateral silent period (CSP), a measure of corticospinal inhibition evaluated using transcranial magnetic stimulation (TMS), is inconsistent in literature. We envisioned that investigating CSP across muscles with varying degrees of weakness may be a reasonable approach to resolve inconsistencies and elucidate the relevance of corticospinal inhibition for upper extremity function following SCI.

METHODS

We studied 27 adults with chronic C1-C8 SCI (age 48.8 ± 16.1 years, 3 females) and 16 able-bodied participants (age 33.2 ± 11.8 years, 9 females). CSP characteristics were assessed across biceps (muscle power = 3-5) and triceps (muscle power = 1-3) representing stronger and weaker muscles, respectively. We assessed functional abilities using the Capabilities of the Upper Extremity Test (CUE-T).

RESULTS

Participants with chronic SCI had prolonged CSPs for biceps but delayed and diminished CSPs for triceps compared to able-bodied participants. Early-onset CSPs for biceps and longer, deeper CSPs for triceps correlated with better CUE-T scores.

CONCLUSIONS

Corticospinal inhibition is pronounced for stronger biceps but diminished for weaker triceps muscle in SCI indicating innervation relative to the level of injury matters in the study of CSP.

SIGNIFICANCE

Nevertheless, corticospinal inhibition or CSP holds relevance for upper extremity function following SCI.

Current animal models of extracorporeal cardiopulmonary resuscitation: A scoping review

Aim

Animal models of Extracorporeal Cardiopulmonary Resuscitation (ECPR) focusing on neurological outcomes are required to further the development of this potentially life-saving technology. The aim of this review is to summarize current animal models of ECPR.

Methods

A comprehensive database search of PubMed, EMBASE, and Web of Science was undertaken. Full-text publications describing animal models of ECPR between January 1, 2000, and June 30, 2022, were identified and included in the review. Data describing the conduct of the animal models of ECPR, measured variables, and outcomes were extracted according to pre-defined definitions.

Results

The search strategy yielded 805 unique reports of which 37 studies were included in the final analysis. Most studies (95%) described using a pig model of ECPR with the remainder (5%) describing a rat model. The most common method for induction of cardiac arrest was a fatal ventricular arrhythmia through electrical stimulation (70%). 10 studies reported neurological assessment of animals using physical examination, serum biomarkers, or electrophysiological findings, however, only two studies described a multimodal assessment. No studies reported the use of brain imaging as part of the neurological assessment. Return of spontaneous circulation was the most reported primary outcome, and no studies described the neurological status of the animal as the primary outcome.

Conclusion

Current animal models of ECPR do not describe clinically relevant neurological outcomes after cardiac arrest. Further work is needed to develop models that more accurately mimic clinical scenarios and can test innovations that can be translated to the application of ECPR in clinical medicine.

Longitudinal evolution of Central Nervous System anomalies in fetuses with open spina bifida fetoscopic repair and correlation with neurological outcome

BACKGROUND

Open spina bifida (OSB) is associated with Central Nervous System anomalies, as abnormal Corpus callosum (CC) and heterotopias. However, the impact of prenatal surgery over these structures remains unclear.

OBJECTIVES

To describe longitudinal changes of Central Nervous System anomalies before and after prenatal OSB repair, and to evaluate their relationship with postnatal neurological outcomes.

STUDY DESIGN

Retrospective cohort study of fetuses with OSB who underwent Percutaneous fetoscopic repair from January 2009 to August 2020. All women had pre- and postsurgical fetal Magnetic Resonance (MR), with an average of one week prior and four weeks after surgery, respectively. We evaluated defect characteristics in the presurgical MR; fetal head biometry, clivus supra-occiput angle, and the presence of structural CNS anomalies, as abnormalities in CC, heterotopias, ventriculomegaly (VMG), and hindbrain herniation (HBH) in both pre- and postsurgical MR. Neurological assessment was performed using the Pediatric Evaluation of Disability Inventory (PEDI) scale in children with 12-months or older, covering three different sections: self-care, mobility, and social/cognitive function.

RESULTS

Forty-six fetuses were evaluated. Pre-and post-surgery MR were performed at a median GA of 25.3 and 30.6 weeks, with a median interval of 0.8 weeks prior surgery, and 4.0 weeks after surgery. There was a 70% reduction in HBH (100% vs. 32.6%, p<0.001), and a normalization of the clivus supra-occiput angle after surgery (55.3 (48.8,61.0) vs. 79.9 (75.2,85.4), p<0.001). No significant increase in abnormal CC (50.0% vs. 58.7%, p=0.157) or heterotopia (10.8% vs. 13.0%, p=0.706) was observed. Ventricular dilation was higher after surgery (15.6 (12.7,18.1) vs. 18.8 (13.7,22.9) mm, p<0.001), with a higher proportion of severe ventricular dilation after surgery (≥15mm) (52.2% vs. 67.4%, p=0.020). Thirty-four children underwent neurological assessment, with 50% presenting a global optimal PEDI result and 100% presenting a normal social/cognitive function. Children with optimal global PEDI presented a lower rate of presurgical anomalies in CC and severe VMG. When analyzed as independent variables to global PEDI scale, the presence of abnormal CC and severe VMG showed an Odds-Ratio of 27.7 (p=0.025, CI 1.53-500.71) for a suboptimal result.

CONCLUSIONS

Prenatal OSB repair did not change the proportion of abnormal CC nor heterotopias after surgery. The combination of presurgical abnormal CC and severe ventricular dilation (≥ 15 mm) is associated with an increased risk of suboptimal neurodevelopment.

Literature review of stroke assessment for upper-extremity physical function via EEG, EMG, kinematic, and kinetic measurements and their reliability

BACKGROUND

Significant clinician training is required to mitigate the subjective nature and achieve useful reliability between measurement occasions and therapists. Previous research supports that robotic instruments can improve quantitative biomechanical assessments of the upper limb, offering reliable and more sensitive measures. Furthermore, combining kinematic and kinetic measurements with electrophysiological measurements offers new insights to unlock targeted impairment-specific therapy. This review presents common methods for analyzing biomechanical and neuromuscular data by describing their validity and reporting their reliability measures.

METHODS

This paper reviews literature (2000-2021) on sensor-based measures and metrics for upper-limb biomechanical and electrophysiological (neurological) assessment, which have been shown to correlate with clinical test outcomes for motor assessment. The search terms targeted robotic and passive devices developed for movement therapy. Journal and conference papers on stroke assessment metrics were selected using PRISMA guidelines. Intra-class correlation values of some of the metrics are recorded, along with model, type of agreement, and confidence intervals, when reported.

RESULTS

A total of 60 articles are identified. The sensor-based metrics assess various aspects of movement performance, such as smoothness, spasticity, efficiency, planning, efficacy, accuracy, coordination, range of motion, and strength. Additional metrics assess abnormal activation patterns of cortical activity and interconnections between brain regions and muscle groups; aiming to characterize differences between the population who had a stroke and the healthy population.

CONCLUSION

Range of motion, mean speed, mean distance, normal path length, spectral arc length, number of peaks, and task time metrics have all demonstrated good to excellent reliability, as well as provide a finer resolution compared to discrete clinical assessment tests. EEG power features for multiple frequency bands of interest, specifically the bands relating to slow and fast frequencies comparing affected and non-affected hemispheres, demonstrate good to excellent reliability for populations at various stages of stroke recovery. Further investigation is needed to evaluate the metrics missing reliability information. In the few studies combining biomechanical measures with neuroelectric signals, the multi-domain approaches demonstrated agreement with clinical assessments and provide further information during the relearning phase. Combining the reliable sensor-based metrics in the clinical assessment process will provide a more objective approach, relying less on therapist expertise. This paper suggests future work on analyzing the reliability of metrics to prevent biasedness and selecting the appropriate analysis.

Assessment of motor limb strength by neuroscience nurses: variations in practice and associated challenges

BACKGROUND

Limb strength is a central component of neurological assessment and monitoring in nursing practice, yet there is a lack of research examining the tools used by nurses or challenges nurses encounter when using these tools. The evidence base is lacking to inform effective practice and the underpinning educational approaches.

AIM

To determine which tools are used by UK and Irish neuroscience nurses in the assessment of limb strength and the associated challenges and variations in practice.

METHODS

This study used an online self-reported survey design to ascertain which tools neuroscience nurses used and their experience of using these (n=160).

FINDINGS

Practices varied, with a dominance of two tools being used in practice: the Medical Research Council scale and the 'normal power' to 'no movement' scale found on the neurological observation chart. Most respondents used the same tool across all conditions.

CONCLUSION

This study highlights variations in assessment practice and the absence of a sound evidence base behind choice of motor limb strength assessment tools used.

Effects of a multifaceted neurological assessment educational program in nursing students: A randomized crossover study

AIM

This study aimed to verify the effects of a multifaceted neurological assessment educational program on neurological assessment-related knowledge, skills, communication ability and self-efficacy in nursing students.

BACKGROUND

Nurses should be equipped with optimal neurological assessment competency to ensure quality care for patients with neurological symptoms.

DESIGN

This study involved a waitlist control group with a randomized crossover design.

METHODS

Fourth-year nursing students were randomly assigned to an intervention group (n = 28) or a waitlist control group (n = 27). Pre- and post-intervention differences in neurological assessment knowledge, skills, communication ability and self-efficacy between the intervention and the waitlist control group were analyzed using generalized estimated equations.

RESULTS

The nursing students in the intervention group showed significantly improved knowledge, skills, communication ability and self-efficacy scores compared with those in the waitlist control group. Scores related to knowledge, skills and communication ability were maintained and self-efficacy scores had further increased at 2 weeks after the educational program in the intervention group.

CONCLUSIONS

Our multifaceted neurological assessment educational program is useful for improving nursing students' knowledge, skills, communication ability and self-efficacy.

Combination of Endothelin-1 (ET-1) and L-NAME to Induce Murine Focal Cortical Stroke with Persistent Sensorimotor Deficits

The endothelin-1 (ET-1) model of stroke involves the stereotactic injection of the vasoconstrictor ET-1 to produce a focal ischemic injury. In rats, this model produces consistent deficits, in contrast to more variable results in mice. In this chapter, we describe a new method to induce a murine focal ischemic cortical stroke by injecting L-NAME, another potent vasoconstrictor , in combination with ET-1 into the sensorimotor cortex. This ET-1 /L-NAME stroke induction protocol produces consistent focal cortical infarcts and sensorimotor functional impairments in C57BL/6 mice.

Insights into motor performance deficits after stroke: an automated and refined analysis of the lower-extremity motor coordination test (LEMOCOT)

Background

The lower-extremity motor coordination test (LEMOCOT) is a performance-based measure used to assess motor coordination deficits after stroke. We aimed to automatically quantify performance on the LEMOCOT and to extract additional performance parameters based on error analysis in persons with stroke (PwS) and healthy controls. We also aimed to explore whether these parameters provide additional information regarding motor control deficit that is not captured by the traditional LEMOCOT score. In addition, the associations between the LEMOCOT score, parameters of error and performance-based measures of lower-extremity impairment and gait were tested.

Methods

Twenty PwS (age: 62 ± 11.8 years, time after stroke onset: 84 ± 83 days; lower extremity Fugl-Meyer: 30.2 ± 3.7) and 20 healthy controls (age: 42 ± 15.8 years) participated in this cross-sectional exploratory study. Participants were instructed to move their big toe as fast and accurately as possible between targets marked on an electronic mat equipped with force sensors (Zebris FDM-T, 60 Hz). We extracted the contact surface area of each touch, from which the endpoint location, the center of pressure (COP), and the distance between them were computed. In addition, the absolute and variable error were calculated.

Results

PwS touched the targets with greater foot surface and demonstrated a greater distance between the endpoint location and the location of the COP. After controlling for the number of in-target touches, greater absolute and variable errors of the endpoint were observed in the paretic leg than in the non-paretic leg and the legs of controls. Also, the COP variable error differentiated between the paretic, non-paretic, and control legs and this parameter was independent of in-target counts. Negative correlations with moderate effect size were found between the Fugl Meyer assessment and the error parameters.

Conclusions

PwS demonstrated lower performance in all outcome measures than did controls. Several parameters of error indicated differences between legs (paretic leg, non-paretic leg and controls) and were independent of in-target touch counts, suggesting they may reflect motor deficits that are not identified by the traditional LEMOCOT score.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12984-021-00950-z.

Development of a clinical scale for assessment of patients with diffuse intrinsic pontine glioma (DIPG) receiving experimental therapy: the PONScore

PURPOSE

Monitoring neurological side-effects in experimental therapy for diffuse intrinsic pontine glioma (DIPG) can be challenging. We aimed to develop a neurological scale that could be used by non-specialists to quantify neurological changes during experimental treatment of DIPG.

METHODS

We developed the Pontine Observational Neurological Score (PONScore) to measure signs and symptoms of DIPG by adapting validated assessment scales of neurological signs and symptoms in children. We developed a prototype score, taught it to paediatric intensive care nursing staff, who used the Score to assess children receiving awake pontine infusion of chemotherapy for treatment of DIPG. We used their feedback to develop the PONScore. Points are allocated for headache, ophthalmoplegia, facial and tongue weakness, dysarthria, paraesthesia, limb weakness and dysmetria with increasing scores reflecting increasing disability. The PONScore was administered every hour during awake pontine infusion. Correlation and agreement calculations between nursing staff, as non-specialists, and a specialist rater were performed in 30 infusions in 6 children (aged 8-11). Changes in PONScore versus volume of infusion are described in a further 55 infusions in 8 children (aged 3-11).

RESULTS

The PONScore demonstrated excellent intra-rater reliability with an intra-class co-efficient of 0.98 (95% CI 0.97-0.99; p-value < 0.001) between a specialist and non-specialist raters with strong correlation between scores and a Spearman correlation coefficient of 0.985 (p < 0.001). PONScores increased from 3.3 to 5.7 (p-value < 0.001) during infusion reflecting accumulation of neurological signs and symptoms during infusion.

CONCLUSIONS

We describe a novel neurological scale that can be used by non-specialists to describe acute neurological changes in children receiving experimental therapy for DIPG. Prospective validation as part of a clinical trial is required.

Towards individualized cortical thickness assessment for clinical routine

Background

Cortical thickness measures the width of gray matter of the human cortex. It can be calculated from T1-weighted magnetic resonance images (MRI). In group studies, this measure has been shown to correlate with the diagnosis/prognosis of a number of neurologic and psychiatric conditions, but has not been widely adapted for clinical routine. One of the reasons for this might be that there is no reference system which allows to rate individual cortical thickness data with respect to a control population.

Methods

To address this problem, this study compared different methods to assess statistical significance of cortical thinning, i.e. atrophy. All compared methods were nonparametric and encompassed rating an individual subject’s data set with respect to a control data population. Null distributions were calculated using data from the Human Connectome Project (HCP, n = 1000), and an additional HCP data set (n = 113) was used to calculate sensitivity and specificity to compare the different methods, whereas atrophy was simulated for sensitivity assessment. Validation measures were calculated for the entire cortex (“cumulative”) and distinct brain regions (“regional”) where possible.

Results

The approach yielding the highest combination of specificity and sensitivity implemented generating null distributions for anatomically distinct brain regions, based on the most extreme values observed in the population. With that method, while regional variations were observed, cumulative specificity of 98.9% and cumulative sensitivity at 80% was achieved for simulated atrophy of 23%.

Conclusions

This study shows that validated rating of individual cortical thickness measures is possible, which can help clinicians in their daily routine to discover signs of atrophy before they become visually apparent on an unprocessed MRI. Furthermore, given different pathologies present with distinct atrophy patterns, the regional validation proposed here allows to detect distinct patterns of atrophy, which can further enhance differential diagnosis/prognosis.

Quantified pre-operative neurological dysfunction predicts outcome after coronary artery bypass surgery

AIMS

Patients undergoing coronary artery bypass grafting (CABG) surgery may experience neurological impairment. We examined whether intraoperative regional cerebral oxygen saturation (rSO₂) and neurological dysfunction prior to surgery, measured by robotic technology, are important predictors of post-operative performance following CABG surgery.

METHODS

Adult patients undergoing CABG surgery were recruited for this single-center prospective observational study. Intraoperative rSO₂ was captured using the FORESIGHT cerebral oximeter. Neurological assessment was performed pre-operatively and 3 months following surgery using robotic technology and a standardized pen-and-paper assessment. Linear regression models were generated to determine the predictive ability of both intraoperative rSO₂ and pre-operative performance on post-operative neurological outcome.

RESULTS

Forty patients had complete data available for analysis. Quantified pre-operative performance accounted for a significantly larger amount of variance in post-operative outcome compared to intraoperative rSO₂. In particular, pre-operative scoring on a cognitive visuospatial task accounted for 82.2% of variance in post-operative performance (b = 0.937, t(37) = 12.98, p = 1.28e-5).

DISCUSSION

Our results suggest that pre-operative performance is a stronger indicator of post-operative neurological outcome than intraoperative rSO₂, and should be included as an important variable when elucidating the relationship between cerebral oxygen levels and post-operative neurological impairment. Rigorous neurological assessment prior to surgery can provide valuable information about each individual patient's path to recovery.

CONCLUSION

Using robotic technology, quantified neurological impairment prior to CABG surgery may better predict post-operative neurological outcomes, compared to intraoperative rSO₂ values.

Motor abnormalities and cognitive impairment in first-episode psychosis patients, their unaffected siblings and healthy controls

Motor abnormalities (MAs) may be already evidenced long before the beginning of illness and are highly prevalent in psychosis. However, the extent to which the whole range of MAs are related to cognitive impairment in psychosis remains understudied. This study aimed to examine comparatively the relationships between the whole range of motor abnormalities and cognitive impairments in the first-episode of psychosis (FEP), their unaffected siblings and healthy control subjects. Fifty FEP patients, 21 of their healthy siblings and 24 age- and sex matched healthy controls were included. Motor assessment included catatonic, extrapyramidal and neurological soft signs (NSS) by means of standardized instruments. An exhaustive neuropsychological battery was also performed to extract the 7 cognitive dimensions of MATRICS initiative. Higher scores on NSS but not on extrapyramidal and catatonic signs showed significant associations with worse cognitive performance in the three study groups. However, the pattern of associations regarding specific cognitive functions was different among the three groups. Moreover, extrapyramidal signs showed significant associations with cognitive impairment only in FEP patients but not in their unaffected siblings and healthy controls. Catatonic signs did not show any significant association with cognitive functioning in the three study groups. These findings add evidence to the associations between motor abnormalities, particularly NSS and extrapyramidal signs, and cognitive impairment in first-episode psychosis patients. In addition, our results suggest that the specific pattern of associations between MAs and cognitive functioning is different in FEP patients from those of the unaffected siblings and healthy subjects.

Motor abnormalities in first-episode psychosis patients and long-term psychosocial functioning

Motor abnormalities (MAs) are highly prevalent in patients with first-episode psychosis both before any exposure and after treatment with antipsychotic drugs. However, the extent to which these abnormalities have predictive value for long-term psychosocial functioning is unknown. One hundred antipsychotic-naive first-episode psychosis (FEP) patients underwent extensive motor evaluation including catatonic, parkinsonism, dyskinesia, akathisia and neurological soft signs. Patients were assessed at naïve state and 6months later. Patients were followed-up in their naturalistic treatment and settings and their psychosocial functioning was assessed at 6-month, 1year, 5year and 10years from the FEP by collecting all available information. A set of linear mixed models were built to account for the repeated longitudinal assessment of psychosocial functioning during the follow-up regarding to the five domains of MAs (catatonic, parkinsonism, akathisia, dyskinesia and neurologic soft-signs) at index episode at antipsychotic naïve state and after 6months of FEP. Basic epidemiological variables, schizophrenia diagnosis and average of chlorpromazine equivalent doses of antipsychotic drugs were included as covariates. Catatonic signs and dyskinesia at drug-naïve state were significantly associated with poor long-term psychosocial functioning. Moreover, higher scores on parkinsonism, akathisia, neurological soft signs and catatonic signs at 6-month of FEP but not dyskinesia showed significant associations with poor long-term psychosocial functioning. Our results added empirical evidence to motor abnormalities as core manifestations of psychotic illness before and after antipsychotic treatment with high predictive value for poor long-term psychosocial functioning in FEP patients.

Neurological Assessment Using a Quantitative Sensory Test in Patients with Chronic Unilateral Orofacial Pain

Background:

Quantitative Sensory Testing (QST) has been used in clinical and experimental settings to establish sensory assessment for different types of pains, and may be a useful tool for the assessment of orofacial pain, but this premise needs to be tested.

Objective:

The aim of the study was to evaluate responses to thermal stimuli between painful and non-painful facial sites in subjects with orofacial pain using QST.

Methods:

A total of 60 participants (5o females: 28-83 years; 10 males: 44-81 years) with unilateral orofacial pain were recruited from the Orofacial Pain Clinic at the Pain Management and Research Centre, Royal North Shore Hospital, Sydney, Australia. The study followed the methods of limits of the German Research Network testing four modalities of thermal thresholds, the Warm Sensation, the Cold Sensation, the Heat Pain and the Cold Pain using a TSA-II Neurosensory Analyser. The results were compared to the results from the unaffected side of the same patient on the same area and a single t test statistical analysis was performed, where a p value of less than 0.05 was considered significant.

Results:

The Mean Difference for Cold Sensation between the pain side and the non-pain side was 0.48 °C ± 1.5 (t= 2.466, p=0.017), 0.68 °C ± 2.04 for Warm Sensation (t= -2.573, p= 0.013), 2.56 °C ± 2.74 for Cold Pain (t= 7.238, p<0.001) and -1.21 °C ± 2.59 for Hot Pain (t= -3.639, p=0.001).

Conclusion:

The study showed that QST methods using thermal stimuli could be used to evaluate sensory dysfunction in orofacial pain patients using the specific parameters of cool and warm sensation, and cold and hot pain.

Spinal Cord Injuries

Spinal Cord injury (SCI) is one of the most devastating and demoralizing ailment for both the patient and the medical practitioner. However, with the better understanding of the pathophysiology, better imaging modalities and emphasis on immobilization and rehabilitation has provided a ray of hope to such patients. The initial care aims at immobilization and evacuation by the classical log roll method and focuses on life-saving procedures. Basic imaging should be augmented with an MRI in doubtful cases. Immobilization either external or internal should be followed by early efforts for rehabilitation. The use of steroids during the acute phase has become controversial. The focus of latest studies has shifted to neuroprotective and regenerative agents.