Quantitative Validation of the Correlation Between Optimized Pyramidal Tract Delineation After Brain Shift Compensation and Direct Electrical Subcortical Stimulation During Brain Tumor Surgery.

It remains unclear whether tractography of pyramidal tracts is correlated with the intraoperative direct electrical subcortical stimulation (DESS), and brain shift further complicates the issue. The objective of this research is to quantitatively verify the correlation between optimized tractography (OT) of pyramidal tracts after brain shift compensation and DESS during brain tumor surgery. OT was performed for 20 patients with lesions in proximity to the pyramidal tracts based on preoperative diffusion-weighted magnetic resonance imaging. During surgery, tumor resection was guided by DESS. A total of 168 positive stimulation points and their corresponding stimulation intensity thresholds were recorded. Using the brain shift compensation algorithm based on hierarchical B-spline grids combined with a Gaussian resolution pyramid, we warped the preoperative pyramidal tract models and used receiver operating characteristic (ROC) curves to investigate the reliability of our brain shift compensation method based on anatomic landmarks. Additionally, the minimum distance between the DESS points and warped OT (wOT) model was measured and correlated with DESS intensity threshold. Brain shift compensation was achieved in all cases, and the area under the ROC curve was 0.96 in the registration accuracy analysis. The minimum distance between the DESS points and the wOT model was found to have a significantly high correlation with the DESS stimulation intensity threshold (r = 0.87, P < 0.001), with a linear regression coefficient of 0.96. Our OT method can provide comprehensive and accurate visualization of the pyramidal tracts for neurosurgical navigation and was quantitatively verified by intraoperative DESS after brain shift compensation.

Lateral Corticospinal Tract and Dorsal Column Damage: Predictive Relationships With Motor and Sensory Scores at Discharge From Acute Rehabilitation After Spinal Cord Injury.

OBJECTIVE: To determine if lateral corticospinal tract (LCST) integrity demonstrates a significant predictive relationship with future ipsilateral lower extremity motor function (LEMS) and if dorsal column (DC) integrity demonstrates a significant predictive relationship with future light touch (LT) sensory function post spinal cord injury (SCI) at time of discharge from inpatient rehabilitation. DESIGN: Retrospective analyses of imaging and clinical outcomes. SETTING: University and academic hospital. PARTICIPANTS: A total of 151 participants (N=151) with SCI. INTERVENTIONS: Inpatient rehabilitation. MAIN OUTCOME MEASURES: LEMS and LT scores at discharge from inpatient rehabilitation. RESULTS: In 151 participants, right LCST spared tissue demonstrated a significant predictive relationship with right LEMS percentage recovered (ß=0.56; 95% confidence interval [CI], 0.37-0.73; R=0.43; P<.001). Left LCST spared tissue demonstrated a significant predictive relationship with left LEMS percentage recovered (ß=0.66; 95% CI, 0.50-0.82; R=0.51; P<.001). DC spared tissue demonstrated a significant predictive relationship with LT percentage recovered (ß=0.69; 95% CI, 0.52-0.87; R=0.55; P<.001). When subgrouping the participants into motor complete vs incomplete SCI, motor relationships were no longer significant, but the sensory relationship remained significant. Those who had no voluntary motor function but recovered some also had significantly greater LCST spared tissue than those who did not recover motor function. CONCLUSIONS: LCST demonstrated significant moderate predictive relationships with lower extremity motor function at the time of discharge from inpatient rehabilitation, in an ipsilesional manner. DC integrity demonstrated a significant moderate predictive relationship with recovered function of LT. With further development, these neuroimaging methods might be used to predict potential deficits after SCI and to provide corresponding targeted interventions.

Optimized Tractography Mapping and Quantitative Evaluation of Pyramidal Tracts for Surgical Resection of Insular Gliomas: a Correlative Study with Diffusion Tensor Imaging-Derived Metrics and Patient Motor Strength.

We investigate the correlation between diffusion tensor imaging (DTI)-derived metric statistics and motor strength grade of insular glioma patients after optimizing the pyramidal tract (PT) delineation. Motor strength grades of 45 insular glioma patients were assessed. All the patients underwent structural and diffusion MRI examination before and after surgery. We co-registered pre- and post-op datasets, and a two-tensor unscented Kalman filter (UKF) algorithm was employed to delineate bilateral PTs after DWI pre-processing. The tractography results were voxelized, and their labelmaps were cropped according to the location of frontal and insular parts of the lesion. Both the whole and cropped labelmaps were used as regions of interest to analyze fractional anisotropy (FA) and Trace statistics; hence, their ratios were calculated (lesional side tract/contralateral normal tract). The combination of DWI pre-processing and two-tensor UKF algorithm successfully delineated bilateral PTs of all the patients. It effectively accomplished both full fiber delineation within the edema and an extensive lateral fanning that had a favorable correspondence to the bilateral motor cortices. Before surgery, correlations were found between patients' motor strength grades and ratios of PT volume and FA standard deviation (SD). Nearly 3 months after surgery, correlations were found between motor strength grades and the ratios of metric statistics as follows: whole PT volume, whole mean FA, and FA SD. We substantiated the correlation between DTI-derived metric statistics and motor strength grades of insular glioma patients. Moreover, we posed a workflow for comprehensive pre- and post-op DTI quantitative research of glioma patients.

Mapping the corticoreticular pathway from cortex-wide anterograde axonal tracing in the mouse.

The corticoreticular pathway (CRP) has been implicated as an important mediator of motor recovery and rehabilitation after central nervous system damage. However, its origins, trajectory and laterality are not well understood. This study mapped the mouse CRP in comparison with the corticospinal tract (CST). We systematically searched the Allen Mouse Brain Connectivity Atlas (© 2011 Allen Institute for Brain Science) for experiments that used anterograde tracer injections into the right isocortex in mice. For each eligible experiment (N = 607), CRP and CST projection strength were quantified by the tracer volume reaching the reticular formation motor nuclei (RFmotor ) and pyramids, respectively. Tracer density in each brain voxel was also correlated with RFmotor versus pyramids projection strength to explore the relative trajectories of the CRP and CST. We found significant CRP projections originating from the primary and secondary motor cortices, anterior cingulate, primary somatosensory cortex, and medial prefrontal cortex. Compared with the CST, the CRP had stronger projections from each region except the primary somatosensory cortex. Ipsilateral projections were stronger than contralateral for both tracts (above the pyramidal decussation), but the CRP projected more bilaterally than the CST. The estimated CRP trajectory was anteromedial to the CST in the internal capsule and dorsal to the CST in the brainstem. Our findings reveal a widespread distribution of CRP origins and confirm strong bilateral CRP projections, theoretically increasing the potential for partial sparing after brain lesions and contralesional compensation after unilateral injury.

Blowing up Neural Repair for Stroke Recovery: Preclinical and Clinical Trial Considerations.

The repair and recovery of the brain after stroke is a field that is emerging in its preclinical science and clinical trials. However, recent large, multicenter clinical trials have been negative, and conflicting results emerge on biological targets in preclinical studies. The coalescence of negative clinical translation and confusion in preclinical studies raises the suggestion that perhaps the field of stroke recovery faces a fate similar to stroke neuroprotection, with interesting science ultimately proving difficult to translate to the clinic. This review highlights improvements in 4 areas of the stroke neural repair field that should reorient the field toward successful clinical translation: improvements in rodent genetic models of stroke recovery, consideration of the biological target in stroke recovery, stratification in clinical trials, and the use of appropriate clinical trial end points.

Recovery and Prediction of Dynamic Precision Grip Force Control After Stroke.

Background and Purpose- Dexterous object manipulation, requiring generation and control of finger forces, is often impaired after stroke. This study aimed to describe recovery of precision grip force control after stroke and to determine clinical and imaging predictors of 6-month performance. Methods- Eighty first-ever stroke patients with varying degrees of upper limb weakness were evaluated at 3 weeks, 3 months, and 6 months after stroke. Twenty-three healthy individuals of comparable age were also studied. The Strength-Dexterity test was used to quantify index finger and thumb forces during compression of springs of varying length in a precision grip. The coordination between finger forces (CorrForce), along with Dexterity-score and Repeatability-score, was calculated. Anatomical magnetic resonance imaging was used to calculate weighted corticospinal tract lesion load (wCST-LL). Results- CorrForce, Dexterity-score, and Repeatability-score in the affected hand were dramatically lower at each time point compared with the less-affected hand and the control group, even in patients with mild motor impairment according to Fugl-Meyer assessment. Improved performance over time occurred in CorrForce and Dexterity-score but not in Repeatability-score. The Fugl-Meyer assessment hand subscale, sensory function, and wCST-LL best predicted CorrForce and Dexterity-score status at 6 months (R2=0.56 and 0.87, respectively). wCST-LL explained substantial variance in CorrForce (R2=0.34) and Dexterity-score (R2=0.50) at 6 months; two-point discrimination and Fugl-Meyer score accounted for considerable additional variance. Absence of recovery in CorrForce was predicted by wCST-LL >4 cc and in Dexterity-score by wCST-LL >6 cc. Conclusions- Findings highlight persisting deficits in the ability to grasp and control finger forces after stroke. wCST-LL was the strongest predictor of performance at 6 months, but early two-point discrimination and Fugl-Meyer score had substantial additional predictive value. Registration- URL: https://www.clinicaltrials.gov. Unique identifier: NCT02878304.

Corticospinal Tract Injury Estimated From Acute Stroke Imaging Predicts Upper Extremity Motor Recovery After Stroke.

Background and Purpose- Injury to the corticospinal tract (CST) has been shown to have a major effect on upper extremity motor recovery after stroke. This study aimed to examine how well CST injury, measured from neuroimaging acquired during the acute stroke workup, predicts upper extremity motor recovery. Methods- Patients with upper extremity weakness after ischemic stroke were assessed using the upper extremity Fugl-Meyer during the acute stroke hospitalization and again at 3-month follow-up. CST injury was quantified and compared, using 4 different methods, from images obtained as part of the stroke standard-of-care workup. Logistic and linear regression were performed using CST injury to predict ΔFugl-Meyer. Injury to primary motor and premotor cortices were included as potential modifiers of the effect of CST injury on recovery. Results- N=48 patients were enrolled 4.2±2.7 days poststroke and completed 3-month follow-up (median 90-day modified Rankin Scale score, 3; interquartile range, 1.5). CST injury distinguished patients who reached their recovery potential (as predicted from initial impairment) from those who did not, with area under the curve values ranging from 0.70 to 0.8. In addition, CST injury explained ≈20% of the variance in the magnitude of upper extremity recovery, even after controlling for the severity of initial impairment. Results were consistent when comparing 4 different methods of measuring CST injury. Extent of injury to primary motor and premotor cortices did not significantly influence the predictive value that CST injury had for recovery. Conclusions- Structural injury to the CST, as estimated from standard-of-care imaging available during the acute stroke hospitalization, is a robust way to distinguish patients who achieve their predicted recovery potential and explains a significant amount of the variance in poststroke upper extremity motor recovery.

The Relationship Between Leukoaraiosis Involving Contralateral Corticobulbar Tract and Dysphagia in Patients with Acute Unilateral Corona Radiata Infarction with Corticobulbar Tract Involvement.

This study investigated the impact of leukoaraiosis (LA) involving the contralateral corticobulbar tract (CBT) on dysphagia in patients with unilateral corona radiata (CR) infarction with CBT involvement. Patients admitted to the Department of Neurology (September 2011-August 2014) were evaluated; those with a first episode of acute unilateral CR infarction involving the CBT and with LA were included. The 'Case' group comprised patients with LA involving the contralateral CBT; the 'Control' group comprised patients with LA not involving the contralateral CBT. The primary outcome was the feeding method at discharge; secondary outcomes were the feeding method at admission and results of the bedside swallowing test, videofluoroscopic swallowing study (VFSS), videofluoroscopic dysphagia scale, penetration-aspiration scale, American Speech-Language-Hearing Association National Outcome Measurement System Swallowing Scale (ASHA NOMS), oral transit time, and pharyngeal transit time. Infarct size was measured using brain magnetic resonance imaging; LA severity was rated using the Fazekas scale. Eighty-one patients were included (mean age 64.6 ± 11.5 years; 64% male; Case group: 20, 5 underwent VFSS; Control group: 67, 11 underwent VFSS). The Case group was older and had higher total Fazekas scale score than the Control group. The feeding method at discharge and ASHA NOMS score were significantly worse in the Case group than in the Control group. Multivariate analysis revealed that LA involving the contralateral CBT independently predicted the feeding method at discharge and ASHA NOMS score. In conclusion, LA involving the contralateral CBT is associated with dysphagia in patients with unilateral CR infarction involving the CBT.

Neuroimaging Identifies Patients Most Likely to Respond to a Restorative Stroke Therapy.

BACKGROUND AND PURPOSE: Patient heterogeneity reduces statistical power in clinical trials of restorative therapies. Valid predictors of treatment responsiveness are needed, and several have been studied with a focus on corticospinal tract (CST) injury. We studied performance of 4 such measures for predicting behavioral gains in response to motor training therapy. METHODS: Patients with subacute-chronic hemiparetic stroke (n=47) received standardized arm motor therapy, and change in arm Fugl-Meyer score was calculated from baseline to 1 month post-therapy. Injury measures calculated from baseline magnetic resonance imaging included (1) percent CST overlap with stroke, (2) CST-related atrophy (cerebral peduncle area), (3) CST integrity (fractional anisotropy) in the cerebral peduncle, and (4) CST integrity in the posterior limb of internal capsule. RESULTS: Percent CST overlap with stroke, CST-related atrophy, and CST integrity did not correlate with one another, indicating that these 3 measures captured independent features of CST injury. Percent injury to CST significantly predicted treatment-related behavioral gains (r=-0.41; P=0.004). The other CST injury measures did not, neither did total infarct volume nor baseline behavioral deficits. When directly comparing patients with mild versus severe injury using the percent CST injury measure, the odds ratio was 15.0 (95% confidence interval, 1.54-147; P<0.005) for deriving clinically important treatment-related gains. CONCLUSIONS: Percent CST injury is useful for predicting motor gains in response to therapy in the setting of subacute-chronic stroke. This measure can be used as an entry criterion or a stratifying variable in restorative stroke trials to increase statistical power, reduce sample size, and reduce the cost of such trials.

Why Are Only Some Subcortical Ischemic Lesions on Diffusion Magnetic Resonance Imaging Associated With Stroke Symptoms in Small Vessel Disease?

Background and Purpose- In cerebral small vessel diseases, small subcortical ischemic lesions (SSIL) on diffusion imaging are responsible for stroke manifestations but can also be occasionally observed in the absence of overt neurological symptoms. We aimed to determine, in a large cohort of young patients with CADASIL (Cerebral Autosomal-Dominant Arteriopathy With Subcortical Infarcts and Leukoencephalopathy), a severe monogenic condition leading to SSIL in young patients, the characteristics of SSIL and of surrounding cerebral tissue associated with the presence of stroke symptoms. Methods- Among a cohort of 323 genetically confirmed CADASIL patients who were systematically evaluated every 18 months clinically and with magnetic resonance imaging, we studied all visible SSIL and documented ischemic stroke events with available magnetic resonance imaging data. We used mixed-effect logistic regression models to determine whether the presence of stroke symptoms was associated with age, sex, the volume of SSIL, their location with respect to preexisting white matter hyperintensities and with the load of the different magnetic resonance imaging markers of small vessel disease. Results- We identified 73 SSIL (30 with stroke symptoms and 43 without) in 55 patients. In multivariable models, stroke symptoms were more frequent in male patients (estimate=1.94; SE=0.82; P=0.03) and less frequent when SSIL appeared in contact to preexisting white matter hyperintensities (estimate=-2.12; SE=0.83; P=0.01). Within pyramidal tracts, stroke symptoms were more frequent in patients with extensive white matter hyperintensities (estimate=3.8×10-5; SE=9.3×10-6; P<10-4). Conclusions- Altogether, our results suggest that when SSIL occur, the presence of stroke symptoms may depend on sex and alterations of the surrounding brain tissue rather than on the characteristics of the SSIL itself.

Effectiveness of navigation-guided cyst aspiration before resection of large cystic brain tumors: a proof of concept for more radical surgery.

BACKGROUND: Resection of tumors close to the corticospinal tract (CST) carries a high risk of damage to the CST. For cystic tumors, aspirating the cyst before resection may reduce the risk of damage to vital structures. This study evaluated the effectiveness of cyst aspiration, by comparing the results before and after aspiration of diffusion tensor image (DTI) tractography. METHODS: This study enrolled 23 patients with large cystic brain tumors (>20 cm3) between 2012 and 2016. All underwent magnetic resonance imaging (MRI), including DTI tractography, followed by navigation-guided aspiration of the cyst and subsequent tumor resection via craniotomy. Distances between the tumor margin and CST before and after cyst aspiration, volume reduction, and postoperative outcomes were assessed. RESULTS: Median tumor volume decreased from 88 cm3 (range, 25-153) to 29 cm3 (range, 20-80) and distances between tumor margins and the CST increased from 5.7 mm (range, 0.6-22.0) to 14.8 mm (range, 0.6-41.4) after aspiration. Neurological symptoms of patients immediately improved after cyst aspiration. All patients, except for one with a secondary glioblastoma, underwent gross total resection of the tumor. No neurological deterioration was observed after tumor resection. CONCLUSIONS: Navigation-guided cyst aspiration followed by resection is a useful and safe procedure for brain tumors with large cystic components. Cyst aspiration resulted in expansion of the compressed brain tissue between the tumor margins and vital structures, making maximal safe resection possible.

The brain-derived neurotrophic factor Val66Met polymorphism and degeneration of the corticospinal tract after stroke: a diffusion tensor imaging study.

BACKGROUND AND PURPOSE: A common single nucleotide polymorphism, Val66Met, in the human brain-derived neurotrophic factor (BDNF) gene has a potential role in the pathogenesis and treatment of stroke. The relevance of the BDNF Val66Met polymorphism to long-term stroke outcomes was examined, specifically with respect to changes in corticospinal integrity. METHODS: Thirty-five stroke patients with unilateral motor weakness were genotyped within 2 weeks after onset (T1), and changes in the integrity of the ipsilesional corticospinal tract (CST) as well as alterations in motor function at 1 month (T2) and 3 months after onset (T3) were tracked. RESULTS: On the basis of the Fugl-Meyer assessment upper extremity score, carriers of the Met allele (Val/Met and Met/Met) showed poorer motor outcomes at T2 and T3 compared to carriers of only the Val allele (Val/Val). For both BDNF allele types, patients exhibited characteristic degeneration of the CST compared to healthy controls. There were no differences between the two genotypes with respect to time-dependent changes in diffusion-tensor-imaging-derived parameters of the CST. However, the two groups showed different relationships between motor outcomes and directional diffusivities according to the elapsed time after onset. Poorer motor function was associated with lower axial diffusivity values for the Val/Val genotype group in the sub-acute phase (T1 and T2) but with higher radial diffusivity values for the Val/Met and Met/Met genotype group in the early chronic phase (T3). CONCLUSIONS: Motor recovery in stroke patients may be affected by the BDNF Val66Met polymorphism, possibly through its effects on distinct pathological processes underlying corticospinal degeneration.

TMS-induced motor evoked potentials in Wilson's disease: a systematic literature review.

Wilson's disease (WD) is a metabolic brain disease resulting from improper copper metabolism. Although pyramidal symptoms are rarely observed, subclinical injury is highly possible as copper accumulates in all brain structures. The usefulness of motor evoked potentials (MEPs) in pyramidal tracts damage evaluation still appears to be somehow equivocal. We searched for original papers assessing the value of transcranial magnetic stimulation elicited MEPs with respect to motor function of upper and lower extremity in WD. We searched PubMed for original papers evaluating use of MEPs in WD using key words: "motor evoked potentials Wilson's disease" and "transcranial magnetic stimulation Wilson's disease." We found six articles using the above key words. One additional article and one case report were found while viewing the references lists. Therefore, we included eight studies. Number of patients in studies was low and their clinical characteristic was variable. There were also differences in methodology. Abnormal MEPs were confirmed in 20-70% of study participants. MEPs were not recorded in 7.6-66.7% of patients. Four studies reported significantly increased cortical excitability (up to 70% of patients). Prolonged central motor conduction time was observed in four studies (30-100% of patients). One study reported absent or prolonged central motor latency in 66.7% of patients. Although MEPs may be abnormal in WD, this has not been thoroughly assessed. Hence, further studies are indispensable to evaluate MEPs' usefulness in assessing pyramidal tract damage in WD.

A rare case of ispilateral hemiparesis in a patient with uncrossed pyramidal tract shown by tractography.

This article presents a unique case of ipsilateral hemiparesis in a 66-year-old individual, contrary to the conventional understanding of supratentorial strokes causing contralateral neurological deficits. The patient exhibited persistent weakness and sensory abnormalities on the left side of the body following a left occipital infarct. Neuroimaging revealed a chronic stroke in the left occipital lobe, with diffusion tensor imaging demonstrating uncrossed pyramidal tracts at the level of the medulla. The discussion encompasses the anatomical basis of corticospinal tract crossing, historical perspectives, and previous documented cases of ipsilateral strokes. The rarity of complete uncrossed corticospinal tracts without underlying congenital abnormalities or genetic disorders is highlighted. The study underscores the importance of considering such atypical presentations in stroke evaluations and the role of advanced imaging techniques in confirming diagnosis and understanding underlying mechanisms.

Predictors and Outcomes of Salvaging the Corticospinal Tract After Thrombectomy in Basilar Artery Occlusion Stroke.

Background: Regional eloquence of brainstem structures may contribute to neurological status in basilar artery occlusion (BAO) stroke. The corticospinal tract (CST) which is vulnerable to BAO is important for motor activity. This study investigated the impact of CST salvage on outcomes and its associated factors in patients with BAO treated with thrombectomy. Methods: We retrospectively investigated 88 patients with BAO admitted ≤24 h after onset and presented with motor deficits and who underwent thrombectomy. Patients with a pre-stroke modified Rankin Scale (mRS) score of 4-5 who did not undergo baseline brain computed tomography angiography were excluded. CST salvage was evaluated using follow-up imaging (magnetic resonance imaging [MRI] or computed tomography when MRI was not available) after thrombectomy. A good outcome was defined as a 3-month mRS score of ≤2 or 3 if a patient's pre-stroke mRS score was 3. The associations between CST salvage and outcomes and clinical parameters were analyzed using logistic regression analyses. Results: Thirty-nine (44.3%) patients had CST salvage and the same number of patients had good outcomes. CST salvage was independently associated with a good outcome [adjusted odds ratio (aOR): 18.52, 95% confidence interval (CI): 4.31-79.67, p < 0.001]. After adjusting for confounders, atrial fibrillation (aOR: 3.92, 95% CI: 1.18-13.00, p = 0.026), location of occlusion (mid-BAO; aOR: 0.21, 95% CI: 0.06-0.72, p = 0.013), length of occlusion (involved segment of BAO <2; aOR: 4.77, 95% CI: 1.30-17.59, p = 0.019), and onset-to-puncture-time ≤180 min (aOR: 4.84, 95% CI: 1.13-20.75, p = 0.034) were significantly associated with CST salvage. Conclusion: CST salvage was associated with good functional outcomes in patients with BAO treated with thrombectomy. The presence of atrial fibrillation, location and length of BAO may predict CST salvage after thrombectomy, and rapid treatment with thrombectomy may protect this eloquent tract in these patients.

Mapping the human corticoreticular pathway with multimodal delineation of the gigantocellular reticular nucleus and high-resolution diffusion tractography.

The corticoreticular pathway (CRP) is a major motor tract that transmits cortical input to the reticular formation motor nuclei and may be an important mediator of motor recovery after central nervous system damage. However, its cortical origins, trajectory and laterality are incompletely understood in humans. This study aimed to map the human CRP and generate an average CRP template in standard MRI space. Following recently established guidelines, we manually delineated the primary reticular formation motor nucleus (gigantocellular reticular nucleus [GRN]) using several group-mean MRI contrasts from the Human Connectome Project (HCP). CRP tractography was then performed with HCP diffusion-weighted MRI data (N = 1065) by selecting diffusion streamlines that reached both the cortex and GRN. Corticospinal tract (CST) tractography was also performed for comparison. Results suggest that the human CRP has widespread origins, which overlap with the CST across most of the motor cortex and include additional exclusive inputs from the medial and anterior prefrontal cortices. The estimated CRP projected through the anterior and posterior limbs of the internal capsule before partially decussating in the midbrain tegmentum and converging bilaterally on the pontomedullary reticular formation. Thus, the CRP trajectory appears to partially overlap the CST, while being more distributed and anteromedial to the CST in the cerebrum before moving posterior to the CST in the brainstem. These findings have important implications for neurophysiologic testing, cortical stimulation and movement recovery after brain lesions. We expect that our GRN and tract maps will also facilitate future CRP research.

Neurophysiological Characteristics of Allgrove (Triple A) Syndrome: Case Report and Literature Review.

Allgrove or "Triple A" syndrome is characterized by alacrima, achalasia, and adrenocorticotropic hormone-resistant adrenal insufficiency, as well as central and peripheral nervous system involvement. Patients demonstrate heterogeneity with regard to their age of symptom onset, disease severity, and nature of clinical symptoms. Neurophysiological testing has also shown variability ranging from: motor neuron disease with prominent bulbar involvement, motor-predominant neuropathy, or sensorimotor polyneuropathy with axonal or mixed axonal and demyelinating features. We report an 11-year-old boy who presented with neurological symptoms of progressive spasticity and peripheral neuropathy. His neurophysiological testing confirmed a sensorimotor polyneuropathy with axonal and demyelinating features. Exome sequencing identified compound heterozygote variants in the AAAS gene. We summarize the neurophysiological findings in him and 29 other patients with Allgrove syndrome where nerve conduction study findings were available thereby providing a review of the heterogeneity in neurophysiological findings that have been reported in this rare disorder.

A Comparative Study of Diffusion Fiber Reconstruction Models for Pyramidal Tract Branches.

Currently, comparative studies evaluating the quantification accuracy of pyramidal tracts (PT) and PT branches that were tracked based on four mainstream diffusion models are deficient. The present study aims to evaluate four mainstream models using the high-quality Human Connectome Project (HCP) dataset. Diffusion tensor imaging (DTI), diffusion spectral imaging (DSI), generalized Q-space sampling imaging (GQI), and Q-ball imaging (QBI) were used to construct the PT and PT branches in 50 healthy volunteers from the HCP. False and true PT fibers were identified based on anatomic information. One-way repeated measure analysis of variance and post hoc paired-sample t-test were performed to identify the best PT and PT branch quantification model. The number, percentage, and density of true fibers of PT obtained based on GQI and QBI were significantly larger than those based on DTI and DSI (all p < 0.0005, Bonferroni corrected), whereas false fibers yielded the opposite results (all p < 0.0005, Bonferroni corrected). More trunk branches (PTtrunk) were present in the four diffusion models compared with the upper limb (PTUlimb), lower limb (PTLlimb), and cranial (PTcranial) branches. In addition, significantly more true fibers were obtained in PTtrunk, PTUlimb, and PTLlimb based on the GQI and QBI compared with DTI and DSI (all p < 0.0005, Bonferroni corrected). Finally, GQI-based group probabilistic maps showed that the four PT branches exhibited relatively unique spatial distributions. Therefore, the GQI and QBI represent better diffusion models for the PT and PT branches. The group probabilistic maps of PT branches have been shared with the public to facilitate more precise studies on the plasticity of and the damage to the motor pathway.

Kinematic Measures of Bimanual Performance are Associated With Callosum White Matter Change in People With Chronic Stroke.

OBJECTIVES: To investigate the relationship between bimanual performance deficits measured using kinematics and callosum (CC) white matter changes that occur in people with chronic stroke. DESIGN: Cross-sectional, observational study of participants with chronic stroke and age-matched controls. SETTING: Recruitment and assessments occurred at a stroke recovery research center. Behavioral assessments were performed in a controlled laboratory setting. Magnetic resonance imaging scans were performed at the Center for Biomedical Imaging. PARTICIPANTS: Individuals were enrolled and completed the study (N=39; 21 participants with chronic stroke; 18 age-matched controls with at least 2 stroke risk factors). MAIN OUTCOME MEASURES: Diffusion imaging metrics were obtained for each individual's CC and corticospinal tract (CST), including mean kurtosis (MK) and fractional anisotropy (FA). A battery of motor assessments, including bimanual kinematics, were collected from individuals while performing bimanual reaching. RESULTS: Participants with stroke had lower FA and MK in the CST of the lesioned hemisphere when compared with the non-lesioned hemisphere. The FA and MK values in the CST were correlated with measures of unimanual hand performance. In addition, participants with stroke had significantly lower FA and MK in the CC than matched controls. CC diffusion metrics positively correlated with hand asymmetry and trunk displacement during bimanual performance, even when correcting for age and lesion volume. CONCLUSIONS: These data confirm previous studies that linked CST integrity to unimanual performance and provide new data demonstrating a link between CC integrity and both bimanual motor deficits and compensatory movements.