Revisão de anatomia e correlações clínicas do tronco encefálico, parte i: bulbo / Review of brain anatomy and clinical correlations, part i: medulla

O Tronco encefálico (TE) é uma estrutura singular do sistema nervoso central, pois nele passam tratos sensoriais ascendentes da medula espinal, tratos sensoriais da cabeça e do pescoço, os tratos descendentes motores originados no prosencéfalo (divisão mais rostral do encéfalo), e as vias ligadas aos centros de movimento dos olhos. Contém ainda os núcleos dos nervos cranianos e está envolvido na regulação do nível de consciência através de projeções ao prosencéfalo oriundas da formação reticular. Todas essas estruturas coexistem em um espaço muito exíguo, o que faz com que o TE seja um local muito sensível às alterações patológicas, sendo que os pacientes apresentam muitos sinais neurológicos mesmo com lesões muito pequenas nesse local. Compreender a anatomia interna do TE é essencial para o diagnóstico neurológico e a prática da medicina clínica. Outros profissionais da saúde também se beneficiam desse conhecimento para melhor manejo dos seus pacientes neurológicos. Essa revisão apresenta detalhes da anatomia macroscópica e microscópica do bulbo, bem como seus correlatos clínicos frente às lesões mais comuns dessa divisão particular do TE, conhecidas como síndromes bulbares.

The brainstem is a unique structure in the central nervous system, since it gives way to ascending sensory tracts from the spinal cord, sensory tracts from the head and neck, motor descending tracts originating from the forebrain, and the pathways connected to the eye movement centers. It also contains the cranial nerve nuclei and is involved in the regulation of consciousness levels through projections to the forebrain originating in the reticular formation. All these structures coexist in a very small space, which makes the brainstem very sensitive to pathological changes, with patients presenting several neurological symptoms even with very small brainstem lesions. Understanding the internal anatomy of the brainstem is essential for neurological diagnosis and the practice of clinical medicine. Other health professionals also benefit from this knowledge to better manage their neurological patients. This review presents detailed information on the macroscopic and microscopic anatomy of the medulla, as well as its clinical correlates in the face of the most common lesions of this particular division of the brainstem, known as medullary syndromes.

El tracto cortico espinal: perspectiva histórica / The corticospinal tract: historical perspective

RESUMEN: La neuroanatomía y la neurofisiología han permitido en gran parte entender de forma más integrada las estructuras que conforman el sistema nervioso y los mecanismos asociados con la transmisión de los potenciales de acción, relacionados con la vía corticoespinal en la ejecución de movimientos voluntarios. Se realizó una revisión histórica sobre la vía corticoespinal, desde el punto de vista neuroanatómico y neurofisiológico mediante una revisión de literatura en distintas bases de datos y libros de texto dedicados a estas vías nerviosas. La información obtenida se ordenó cronológicamente, seleccionando los datos más relevantes que desde el punto de vista neuroanatómico y neurofisiológico han permitido comprender su mecanismo funcional. Actualmente se tiene un conocimiento muy depurado de los distintos elementos que componen la vía corticoespinal, lo que permitirá su aplicación en el campo de la salud y resolver múltiples problemas de la función motora.

SUMMARY: Neuroanatomy and Neurophysiology have, in large part, permitted a more thorough understanding of those structures that conform the nervous system and mechanisms associated with the transmission of action potentials associated with the corticospinal tract. This assertion is made based upon a literature review of various databases and textbooks dedicated to said nerve tracts. The information obtained was ordered chronologically, and data was selected that, from the neuroanatomical and neurophysiological viewpoints, were most relevant and have permitted the comprehension of its functional mechanism. The thorough understanding of those elements that compose the corticospinal tract will permit its application in the health field and resolve multiple motor function problems.

Mini-Review of Studies Reporting the Repeatability and Reproducibility of Diffusion Tensor Imaging

PURPOSE: Diffusion tensor imaging (DTI) data must be analyzed by an analyzer after data processing. Hence, the analyzed data of DTI might depend on the analyzer, making it a major limitation. This paper reviewed previous DTI studies reporting the repeatability and reproducibility of data from the corticospinal tract (CST), one of the most actively researched neural tracts on this topic. MATERIALS AND METHODS: Relevant studies published between January 1990 and December 2018 were identified by searching PubMed, Google Scholar, and MEDLINE electronic databases using the following keywords: DTI, diffusion tensor tractography, reliability, repeatability, reproducibility, and CST. As a result, 15 studies were selected. RESULTS: Measurements of the CSTs using region of interest methods on 2-dimensional DTI images generally showed excellent repeatability and reproducibility of more than 0.8 but high variability (0.29 to 1.00) between studies. In contrast, measurements of the CST using the 3-dimensional DTT method not only revealed excellent repeatability and reproducibility of more than 0.9 but also low variability (repeatability, 0.88 to 1.00; reproducibility, 0.82 to 0.99) between studies. CONCLUSION: Both 2-dimensional DTI and 3-dimensional DTT methods appeared to be reliable for measuring the CST but the 3-dimensional DTT method appeared to be more reliable.

Opalski Syndrome Presenting as Sensorimotor Deficits Ipsilateral to Cerebral Infarction

Opalski syndrome is a rare lateral medullary infarction variant presenting with ipsilateral motor deficits known to be caused by involvement of the post-decussating pyramidal tract. Here, we report two rare cases of Opalski syndrome presenting as ipsilateral sensorimotor deficits in cerebral infarction.

Autosomal Recessive Spastic Ataxia of Charlevoix-Saguenay

Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS), which is caused by mutations in SACS gene, is a very rare neurodegenerative disorder characterized by the clinical triad of early onset cerebellar ataxia, pyramidal tract features, and sensorimotor polyneuropathy. Herein, we report a 35-year-old Korean male who presented with gait disturbance and lower extremity weakness. Neuroimaging and ophthalmologic evaluation revealed features consistent with ARSACS. Mutation in SACS gene was demonstrated in clinical exome sequence analysis and the patient was finally diagnosed as ARSACS.

Glial Cell Line-derived Neurotrophic Factor-overexpressing Human Neural Stem/Progenitor Cells Enhance Therapeutic Efficiency in Rat with Traumatic Spinal Cord Injury

Spinal cord injury (SCI) causes axonal damage and demyelination, neural cell death, and comprehensive tissue loss, resulting in devastating neurological dysfunction. Neural stem/progenitor cell (NSPCs) transplantation provides therapeutic benefits for neural repair in SCI, and glial cell line-derived neurotrophic factor (GDNF) has been uncovered to have capability of stimulating axonal regeneration and remyelination after SCI. In this study, to evaluate whether GDNF would augment therapeutic effects of NSPCs for SCI, GDNF-encoding or mock adenoviral vector-transduced human NSPCs (GDNF-or Mock-hNSPCs) were transplanted into the injured thoracic spinal cords of rats at 7 days after SCI. Grafted GDNF-hNSPCs showed robust engraftment, long-term survival, an extensive distribution, and increased differentiation into neurons and oligodendroglial cells. Compared with Mock-hNSPC- and vehicle-injected groups, transplantation of GDNF-hNSPCs significantly reduced lesion volume and glial scar formation, promoted neurite outgrowth, axonal regeneration and myelination, increased Schwann cell migration that contributed to the myelin repair, and improved locomotor recovery. In addition, tract tracing demonstrated that transplantation of GDNF-hNSPCs reduced significantly axonal dieback of the dorsal corticospinal tract (dCST), and increased the levels of dCST collaterals, propriospinal neurons (PSNs), and contacts between dCST collaterals and PSNs in the cervical enlargement over that of the controls. Finally grafted GDNF-hNSPCs substantially reversed the increased expression of voltage-gated sodium channels and neuropeptide Y, and elevated expression of GABA in the injured spinal cord, which are involved in the attenuation of neuropathic pain after SCI. These findings suggest that implantation of GDNF-hNSPCs enhances therapeutic efficiency of hNSPCs-based cell therapy for SCI.

Motor Evoked Potentials in the Upper Extremities of Children with Spastic Hemiplegic Cerebral Palsy

The aim of this study was to evaluate and compare the reorganization of corticospinal pathways innervating upper extremity muscles in patients with spastic hemiplegic cerebral palsy (CP). Thirty-2 patients (17 male, 15 female) with spastic hemiplegic CP were enrolled. The average age (mean ± standard deviation) was 7.5 ± 4.6 (range: 2–17) years. Transcranial magnetic stimulation (TMS) was applied to the unaffected and affected motor cortices in turn, and bilateral electromyographic recordings were made from the first dorsal interossei (FDI), the biceps brachii (BB), and the deltoid muscles during rest. The onset latency, central motor conduction time, and peak-to-peak amplitude of motor evoked potentials (MEPs) were measured for each muscle bilaterally. Whilst TMS of both affected and unaffected hemispheres elicited contralateral MEPs in all muscles, the number of MEPs evoked from the affected hemisphere was less than from the unaffected hemisphere for FDI and BB. TMS responses to stimulation of the affected side showed prolonged latency and reduced amplitude. The amplitudes of MEPs increased with age whereas the latencies were relatively constant. These results suggest that the corticospinal pathways to the proximal and distal muscles of the upper extremity undergo sequential maturation and reorganization patterns.

Delayed Extensive White Matter Injury Caused by a Subdural Hemorrhage and Role of Corticospinal Tract Integrity

A subdural hemorrhage (SDH) is a common disorder with usually good prognosis. Most SDHs resolve with or without with minimal sequelae. We present a case report of a patient with SDH, who had delayed extensive white matter injury with disruptions of corticospinal tracts (CSTs) by diffusion tensor imaging (DTI) and showed abysmal prognosis, despite long-term rehabilitation. A 62-year-old man with an SDH underwent burr hole trephination for hematoma removal. Within 7 days, the hemorrhage diminished. At 12 weeks after the onset, the patient's weakness did not improve, and a follow-up magnetic resonance imaging revealed extensive leukomalacia, especially in the white matter. The DTI for CST revealed severe injury of CST integrity. He did not re-gain muscle strength and functional independence, despite 3 months of inpatient rehabilitation. This case describes SDH with delayed extensive white matter injury and exceptional poor prognosis and urges caution in that the SDH may induce very variable functional recovery. Besides, DTI for CST would be useful in predicting the long-term functional prognosis in extensive white matter injury.

Ten-Year Follow-Up of Transcranial Magnetic Stimulation Study in a Patient With Congenital Mirror Movements: A Case Report

Most studies concerning congenital mirror movements (CMMs) have been focused on the motor organization in the distal hand muscles exclusively. To the best of our knowledge, there is no data on motor organization pattern of lower extremities, and a scarcity of data on the significance of forearm and arm muscles in CMMs. Here, we describe the case of a 19-year-old boy presenting mirror movements. In these terms, a 10-year transcranial magnetic stimulation study demonstrated that the motor organization pattern of the arm muscles was different from that of distal hand and forearm muscles even in the same upper extremity, and that the lower extremities showed the same pathways as healthy children. Moreover, in this case, an ipsilateral motor evoked potentials (MEPs) for distal hand muscles increased in amplitude with age, even though the intensity of mirror movements decreased. In the arm muscles, however, it was concluded that the contralateral MEPs increased in amplitude with age.

Changes in Diffusion Metrics of the Red Nucleus in Chronic Stroke Patients With Severe Corticospinal Tract Injury: A Preliminary Study

OBJECTIVE: To explore plastic changes in the red nucleus (RN) of stroke patients with severe corticospinal tract (CST) injury as a compensatory mechanism for recovery of hand function. METHODS: The moderate group (MG) comprised 5 patients with synergistic hand grasp movement combined with limited extension, and the severe group (SG) included 5 patients with synergistic hand grasp movement alone. The control group (CG) included 5 healthy subjects. Motor assessment was measured by Motricity Index (MI). Diffusion tensor imaging was analyzed using fractional anisotropy (FA) and radial diffusivity (RD) in the individual regions of interest (ROIs)—bilateral internal capsule and anterior pons for CST injury and bilateral RN for rubrospinal tract (RST) injury. RESULTS: The SG showed a significantly lower MI score than the MG mainly due to differences in hand subscores. Significantly reduced FA was observed in both MG and SG compared with CG, while SG showed increased MD and RD in the affected ROIs of CST, and increased FA on the unaffected side compared with CG. However, in the RN ROI, a significantly increased FA and decreased RD on the unaffected side similar to the affected side were found only in the SG. The relative index of FA was lower and RD in SG was higher than in CG in RST. CONCLUSION: The diffusion metrics of RST showed changes in patients with severe CST injury, suggesting that RST may play a role in the recovery of hand function in patients with severe CST injury.

Altered White Matter Integrity in Human Immunodeficiency Virus-Associated Neurocognitive Disorder: A Tract-Based Spatial Statistics Study

OBJECTIVE: Human immunodeficiency virus (HIV) infection has been known to damage the microstructural integrity of white matter (WM). However, only a few studies have assessed the brain regions in HIV-associated neurocognitive disorders (HAND) with diffusion tensor imaging (DTI). Therefore, we sought to compare the DTI data between HIV patients with and without HAND using tract-based spatial statistics (TBSS). MATERIALS AND METHODS: Twenty-two HIV-infected patients (10 with HAND and 12 without HAND) and 11 healthy controls (HC) were enrolled in this study. A whole-brain analysis of fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD), and axial diffusivity was performed with TBSS and a subsequent 20 tract-specific region-of-interest (ROI)-based analysis to localize and compare altered WM integrity in all group contrasts. RESULTS: Compared with HC, patients with HAND showed decreased FA in the right frontoparietal WM including the upper corticospinal tract (CST) and increased MD and RD in the bilateral frontoparietal WM, corpus callosum, bilateral CSTs and bilateral cerebellar peduncles. The DTI values did not significantly differ between HIV patients with and without HAND or between HIV patients without HAND and HC. In the ROI-based analysis, decreased FA was observed in the right superior longitudinal fasciculus and was significantly correlated with decreased information processing speed, memory, executive function, and fine motor function in HIV patients. CONCLUSION: These results suggest that altered integrity of the frontoparietal WM contributes to cognitive dysfunction in HIV patients.

Craniopharyngioma with Intratumoral Hemorrhage and Superficial Siderosis

Superficial siderosis of the central nervous system (CNS) is a progressive and debilitating neurological disease manifesting sensorineural hearing loss, cerebellar ataxia, and pyramidal tract signs. Chronic extravasation of blood into the subarachnoid space results in the accumulation of hemoglobin derivate in the subpial layer of the CNS, which is toxic to the neural tissues. Craniopharyngioma is a benign third ventricle tumor, which rarely presents with tumor bleeding. We report a rare case of superficial siderosis associated with craniopharyngioma with intratumoral hemorrhage in a patient with no history of prior trauma or CNS surgery.

Complex Regional Pain Syndrome of Non-hemiplegic Upper Limb in a Stroke Patient: A Case Report

Complex regional pain syndrome (CRPS) type I in stroke patients is usually known to affect the hemiplegic upper limb. We report a case of CRPS presented in an ipsilesional arm of a 72-year-old female patient after an ischemic stroke at the left middle cerebral artery territory. Clinical signs such as painful range of motion and hyperalgesia of her left upper extremity, swollen left hand, and dystonic posture were suggestive of CRPS. A three-phase bone scintigraphy showed increased uptake in all phases in the ipsilesional arm. Diffusion tensor tractography showed significantly decreased fiber numbers of the corticospinal tract and the spinothalamic tract in both unaffected and affected hemispheres. Pain and range of motion of the left arm of the patient improved after oral steroids with a starting dose of 50 mg/day.

Pyramidal and Proprioceptive Dysfunctions as the Main Neurologic Features in Symptomatic Type I Chiari Malformation Patients

Objective Broader access to magnetic resonance imaging (MRI) has increased the diagnosis of tonsillar ectopia, with most of these patients being asymptomatic. The early diagnosis and treatment of type I Chiari malformation (CM I) patients has impact on the prognosis. This study supplements information about the neurologic exam of symptomatic patients with CM I. Methods The sample was composed of 32 symptomatic patients with CM I diagnosed by a combination of tonsil herniation of more than 5 mm below the magnum foramen (observed in the sagittal T2 MRI) and at least one of the following alterations: intractable occipital headache, ataxia, upper or lower motor neuron impairment, sensitivity deficits (superficial and deep) or lower cranial nerves disorders. Results Occipital headache was the most frequent symptom (53.12%). During the physical exam, the most common dysfunctions were those from the pyramidal system (96.87%), followed by posterior cord syndrome (87.5%). Discussion In this study, patients became symptomatic around the fifth decade of life, which is compatible with previous descriptions. Patients withmore than 2 years of evolution have worse responses to treatment. Occipital headache, symptoms in the upper limbs, gait and proprioceptive disorders are common findings in patients with CM I. Conclusion Deep tendinous reflexes and proprioception disorders were the main neurologic features found in symptomatic CM I patients.

Is Corticospinal Tract Degeneration Caused by Sjögren Syndrome?

No abstract available.

Gait Characteristic in a Stroke Patient with an Intact Corticospinal Tract and Corticoreticular Pathway: A Case Study

PURPOSE: The prefrontal lobe, supplementary motor area, cerebellum, and basal ganglia are activated during gait. In addition, gait is controlled by nerves, such as the corticospinal tract (CST) and corticoreticular pathway (CRP). In this study, the presence of an injury to the CST and CRP was identified by diffusion tensor imaging and the characteristics of the gait pattern were investigated according to inferior cerebral artery infarction. METHODS: One patient and six control subjects of a similar age participated. A 69-year-old female patient had an injury to the left basal ganglia, insular gyrus, corona radiata, dorsolateral prefrontal cortex, and postcentral gyrus due to an inferior cerebral artery infarction. Diffusion tensor imaging (DTI) data was acquired 4 weeks after the stroke. The kinematic and spatio-temporal parameters of gait were collected using a three-dimensional gait analysis system. RESULTS: On 4 weeks DTI, the CST and CRP in the affected hemisphere did not show injury to the affected and unaffected hemisphere. Gait analysis showed that the cadence of spatio-temporal parameter was decreased significantly in the patient. The angle of the knee joint was decreased significantly in the affected and unaffected sides compared to the control group. CONCLUSION: The results of diffusion tensor imaging showed that although the patient was evaluated to be capable of an independent gait, the quality and quantity of gait might be reduced. This study could help better understand the gait ability analysis of stroke patients and the abnormal gait pattern of patients with a brain injury.

Sepsis Associated Encephalopathy Accompanied by Bilateral Corticospinal Tract Lesions in Diffusion Weighed Image

No abstract available.

A Case Report Hemiparesis Caused by Ipsilateral Middle Cerebral Artery Infarction

As the corticospinal tract crosses at the medulla, supratentorial stroke generally influences the opposite extremity. However, new incidences of hemiparesis might occur in the ipsilateral brain if there was a previous infarction in the opposite brain or a congenital structural abnormality. The occurrence of ipsilateral hemiparesis after cerebral infarction is very rare; however, we report here the case of a patient who developed right hemiparesis that was identified as acute right middle cerebral artery infarction.

Hiperintensidad de tracto corticoespinal en resonancia magnética nuclear como signo de lesión de neurona motora superior en esclerosis lateral amiotrófica, reporte de caso y revisión de literatura / High-intensity signal in the corticospinal tract in MRI as a sign of upper motor neuron lesion in amyotrophic lateral sclerosis: Case report and literature review

RESUMEN La esclerosis lateral amiotrófica (ELA) es una enfermedad neurodegenerativa que compromete principalmente el sistema motor. Puede ser adquirida de manera esporádica o hereditaria y presenta una incidencia que varía entre 1.5 a 2.7 casos por 100.000 personas/año, con una mediana de supervivencia de 2 a 4 años. Esta enfermedad está caracterizada por compromiso de ambas motoneuronas, superior e inferior y sus manifestaciones clínicas pueden variar desde leve debilidad muscular en etapas tempranas, hasta falla respiratoria asociada en etapas tardías. El diagnóstico es esencialmente clínico y se hace de acuerdo a los criterios revisados de El Escorial para el diagnóstico de Esclerosis Lateral Amiotrófica (ELA). A pesar de esto, el diagnóstico de ELA en etapas tempranas sigue siendo un reto, lo que retrasa su identificación. Por esta razón surge el interés por identificar nuevos biomarcadores que ayuden al diagnóstico más temprano de la entidad. A continuación se presentará el caso de una mujer de 53 años, a la cual se le realiza un diagnóstico de ELA y en la que se encuentra como hallazgo de resonancia magnética cerebral (RM) cerebral, hiperintensidad bilateral del tracto corticoespinal. Discutiremos en este caso la importancia de los hallazgos en neuroimagen como biomarcador de daño en la enfermedad.

SUMMARY Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder that mainly involves the motor system. It may be sporadic or hereditary, and has an incidence ranging from 1.5 to 2.7 cases per 100,000 persons / year, with a median survival of 2 to 4 years. This disease is characterized by damage of both upper and lower motor neurons, and its clinical manifestations can vary from mild muscle weakness in early stages, to respiratory failure associated in later stages. The diagnosis is based on clinical findings and is made according to the revised El Escorial criteria. Although, the diagnosis of ALS remains a challenge in the early stages and delays it's identification. For this reason, interest to identify new biomarkers that help earlier identification and monitoring of the progression of the disease are being studied. Authors present a case of a woman of 53 years old with a clinical diagnosis of ALS and evidence of corticospinal tract high intensity signal on brain MRI. We will discuss the relevance of brain imaging findings as a biomarker of upper motoneuron damage in ALS.