Clinicopathological features of progressive supranuclear palsy with asymmetrical atrophy of the superior cerebellar peduncle.

Progressive supranuclear palsy (PSP) can be diagnosed despite the presence of asymmetrical parkinsonism depending on the clinical diagnostic criteria. Some studies have reported that atrophy of the superior cerebellar peduncle (SCP) is more frequent in PSP than in Parkinson's disease. There have also been reports of PSP cases with an asymmetrically atrophic SCP. Therefore, we analyzed 48 specimens from consecutive autopsy cases that were neuropathologically diagnosed as PSP to investigate the laterality of brain lesions, including the SCP. We measured the width of the SCP and evaluated the laterality of atrophy. We semi-quantitatively evaluated neuronal loss, atrophy/myelin pallor, and tau pathology in three steps. Asymmetrical atrophy of the SCP was present in seven (14.6%) of 48 cases. The atrophic side of the SCP corresponded to the dominant side of the tau pathology in the cerebellar dentate nucleus. It was opposite to the dominant side of the myelin pallor and tau pathology in the red nucleus and of the tau pathology in the central tegmental tract and inferior olivary nucleus, coinciding with the neurologically systematic anatomy of the Guillain-Mollaret triangle. Neurodegeneration of PSP can progress asymmetrically from one side to the initially intact side in PSP with an initial predominance of Richardson's syndrome, progressive gait freezing, ocular motor dysfunction, parkinsonism, or corticobasal syndrome. To our knowledge, no previous study has reported asymmetrical PSP neuropathology; this is the first study to report the presence of PSP cases with asymmetrical SCP atrophy and systematically asymmetrical degeneration of the Guillain-Mollaret triangle.

Oftalmoplejía internuclear bilateral (WEBINO) en un paciente pediátrico con Lupus Eritematoso Sistémico / Wall-eyed bilateral internuclear ophthalmoplegia (WEBINO) in a pediatric patient with Systemic Lupus Erythematosus

Resumen El síndrome de WEBINO (wall-eyed bilateral internuclear ophthalmoplegia), se presenta por una lesión del tegmento pontino (incluye área pontina paramediana, fascículo longitudinal medial y núcleo del abducens). Presenta limitación bilateral en la aducción y exotropía en la posición de la mirada primaria, nistagmo del ojo que abduce e incapacidad para la convergencia. Reporte de caso: Presentamos el caso de una paciente de 14 años con antecedente de Lupus Eritematoso Sistémico que debutó con diplopía horizontal de inicio súbito. El diagnóstico de WEBINO fue clínico y asociado con hallazgos de lesión isquémico pontomesencefálica en Resonancia Nuclear Magnética y angioresonancia cerebral. Se administró tratamiento con Metilprednisolona y presentó resolución gradual de los síntomas, sin embargo una semana después falleció por criptococosis sistémica. Conclusiones: Hacer el diagnostico de WEBINO se hace desafiante por su rareza y por la precisión de su localización neuroanatómica. Se debe realizar una exploración detallada para definir la causa probable y establecer el tratamiento oportuno que favorezca el pronóstico neurológico.

Background: Wall-eyed bilateral internuclear ophthalmoplegia (WEBINO) is presented by a lesion of the pontine tegment (includes paramedian pontine area, medial longitudinal fascicle and nuclei of the abducens). It presents bilateral limitation in adduction and exotropia in the position of the primary gaze, abducting eye nystagmus and inability to converge. Case report: We present the case of a 14-year-old patient with a history of Systemic Lupus Erythematosus who debuted with sudden onset horizontal diplopia. WEBINO's diagnosis was clinical and associated with findings of ponto-mesencephalic ischemic injury in magnetic resonance imaging and magnetic resonance angiography. Treatment with Methylprednisolone was administered and she presented gradual resolution of the symptoms, however, one week later she died of systemic cryptococcosis. Conclusions: Making the WEBINO diagnosis is challenging due to its rarity and the precision of its neuroanatomical location. A detailed examination should be performed to define the probable cause and establish the appropriate treatment that favors the neurological prognosis.

Neuronophagia and microglial nodules in a SARS-CoV-2 patient with cerebellar hemorrhage.

We document the neuropathologic findings of a 73-year old man who died from acute cerebellar hemorrhage in the context of relatively mild SARS-CoV2 infection. The patient developed sudden onset of headache, nausea, and vomiting, immediately followed by loss of consciousness on the day of admission. Emergency medical services found him severely hypoxemic at home, and the patient suffered a cardiac arrest during transport to the emergency department. The emergency team achieved return of spontaneous circulation after over 17 min of resuscitation. A chest radiograph revealed hazy bilateral opacities; and real-time-PCR for SARS-CoV-2 on the nasopharyngeal swab was positive. Computed tomography of the head showed a large right cerebellar hemorrhage, with tonsillar herniation and intraventricular hemorrhage. One day after presentation, he was transitioned to comfort care and died shortly after palliative extubation. Autopsy performed 3 h after death showed cerebellar hemorrhage and acute infarcts in the dorsal pons and medulla. Remarkably, there were microglial nodules and neuronophagia bilaterally in the inferior olives and multifocally in the cerebellar dentate nuclei. This constellation of findings has not been reported thus far in the context of SARS-CoV-2 infection.

Wall-Eyed Bilateral Internuclear Ophthalmoplegia by Ischemic Stroke: Case Report and Literature Review.

INTRODUCTION: Wall-eyed bilateral internuclear ophthalmoplegia (WEBINO) is a rare symptom. Several studies have reported that a small brainstem lesion could cause WEBINO. CASE REPORT: The authors present the case of an 88-year-old female individual who developed sudden-onset diplopia and gait disturbance. Neurological examination revealed WEBINO with convergence impairment, gaze-evoked upward nystagmus on upward gaze, and bilateral limb ataxia. Brain magnetic resonance imaging revealed a small paramedian pontine tegmentum infarction, responsible for the symptoms. A literature review of WEBINO in ischemic stroke revealed that most patients exhibited impaired convergence and other neurological symptoms. CONCLUSION: Gaze-evoked upward nystagmus on upward gaze and bilateral limb ataxia accompanied by WEBINO due to a small brainstem lesion were the characteristic findings of our case.

Complete horizontal gaze palsy due to bilateral paramedian pontine reticular formation involvement as a presentation of multiple sclerosis: a case report.

BACKGROUND: Demyelinating central nervous system diseases include several disorders that multiple sclerosis (MS) is identified as the most common among them. Ocular movement disturbances are a typical presentation in MS patients where lesions affect the complex and interconnected pathways involved in eye motion. Centers for gaze control are located in the pons primarily; therefore, lesions involving these centers can be presented with abnormalities in gaze. However, bilateral lesions in pontine gaze centers are exceptionally rare. CASE PRESENTATION: A 16-year-old girl with bilateral horizontal gaze palsy was referred to the neurology clinic. Magnetic resonance imaging of the patient indicated bilateral hyperintensities in the pons at the level of the paramedian pontine reticular formation. The patient was diagnosed with multiple sclerosis with respect to clinical and imaging findings and managed. CONCLUSION: Ocular movement abnormalities are a commonly encountered manifestation in patients with multiple sclerosis, however, bilateral gaze palsy is an exceptionally rare sign and should guide the physician to contemplate for anticipated lesions in the pons, and suspect MS, especially in childbearing-aged women. Although an extensive workup should also be done to rule out possible mimickers.

Patterns of pontine strokes mimicking Bell's palsy.

BACKGROUND: Peripheral-type facial palsy very rarely arises from pontine stroke. We attempted to identify unique clinico-radiologic patterns associated with this condition. CASE PRESENTATION: Patients with pontine tegmentum stroke and acute onset of peripheral-type facial weakness were reviewed from the acute stroke registry of a tertiary hospital. The clinico-radiologic patterns of 10 patients were classified into one of three types based on the respective stroke mechanism. Type A (n = 5) was characterized by relatively diverse clinical presentations and larger, multiple infarctions resulting from large-artery atherosclerosis. Three cases with small lacunar infarcts were classified to type B (small vessel occlusion), and they showed only limited symptoms including horizontal gaze disturbance and facial paralysis. The two hemorrhagic cases (type C) presented with a focal pontine hemorrhage, likely due to a cavernous hemangioma. CONCLUSIONS: Peripheral-type facial palsy often occurs in pontine stroke with specific patterns. Type recognition helps to determine the underlying mechanism and the appropriate clinical approach. In particular, focal pontine tegmental infarctions showing stereotypic combinations of ophthalmoplegia and peripheral-type facial weakness (type B) might be recognized as a new type of lacunar syndrome.

Signo de "sal y pimienta" como presentación de una lesión pontina no vascular / "Salt and pepper" sign in the onset of a non-vascular pontine pathology

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Case 266: Pontine Tegmental Cap Dysplasia.

History A 1-year-old boy was referred for cochlear implant assessment after he received a diagnosis of bilateral profound sensorineural hearing loss at neonatal hearing screening shortly after birth. The child was born at term via uneventful delivery, and there was no history of familial hearing loss or maternal illness. Tympanic membranes were normal, and hearing loss was confirmed with auditory brainstem testing, which showed no response from either ear. Hearing aids were provided from 3 months of age, but no behavioral responses were noted when these were worn. He was also noted to have some mild developmental delay throughout his 1st year of life and was slow to crawl, roll over, and stand up. Physical examination showed no syndromic features or physical abnormalities. Ophthalmology confirmed normal vision and visual movements but bilateral anesthetic corneas. He had corneal abrasions due to minor repeated corneal trauma, and left-sided tarsorraphy was performed at 6 months. Facial nerve function, swallow, and voice quality were normal. To assess suitability for a cochlear implant, the patient underwent MRI of the temporal lobe and brain and thin-section CT of the temporal bones. The patient subsequently underwent left cochlear implantation.

Mesopontine cholinergic inputs to midbrain dopamine neurons drive stress-induced depressive-like behaviors.

Stressful life events are primary environmental factors that markedly contribute to depression by triggering brain cellular maladaptations. Dysregulation of ventral tegmental area (VTA) dopamine neurons has been causally linked to the appearance of social withdrawal and anhedonia, two classical manifestations of depression. However, the relevant inputs that shape these dopamine signals remain largely unknown. We demonstrate that chronic social defeat (CSD) stress, a preclinical paradigm of depression, causes marked hyperactivity of laterodorsal tegmentum (LDTg) excitatory neurons that project to the VTA. Selective chemogenetic-mediated inhibition of cholinergic LDTg neurons prevent CSD-induced VTA DA neurons dysregulation and depressive-like behaviors. Pro-depressant outcomes are replicated by pairing activation of LDTg cholinergic terminals in the VTA with a moderate stress. Prevention of CSD outcomes are recapitulated by blocking corticotropin-releasing factor receptor 1 within the LDTg. These data uncover a neuro-circuitry of depressive-like disorders and demonstrate that stress, via a neuroendocrine signal, profoundly dysregulates the LDTg.

Rare occurrence of eight-and-a-half syndrome as a clinically isolated syndrome.

Eight-and-a-half syndrome is a rare condition that is described as a combination of one-and-a-half syndrome and an ipsilateral facial nucleus lesion. We present a clinical case of occurrence of eight-and-a-half syndrome that was caused by a demyelinating lesion in the dorsal pontine tegmentum. A 44-year-old man presented to the hospital with a subacute onset of horizontal diplopia and left-sided facial weakness. MRI revealed a T2 hyperintense lesion in his dorsal pons, which was consistent with a demyelinating pathology. Treatment with intravenous steroids showed significant improvement in his symptoms. In our case, it occurred due to a suspected demyelinating lesion that was this patient's first and only demyelinating event, leaving him with a diagnosis of clinically isolated syndrome. His responsiveness to steroids represents the first case report of an adult patient presenting with an eight-and-a-half syndrome secondary to a suspected demyelinating pathology.

Tinnitus and hyperacusis: Contributions of paraflocculus, reticular formation and stress.

Tinnitus and hyperacusis are common and potentially serious hearing disorders associated with noise-, age- or drug-induced hearing loss. Accumulating evidence suggests that tinnitus and hyperacusis are linked to excessive neural activity in a distributed brain network that not only includes the central auditory pathway, but also brain regions involved in arousal, emotion, stress and motor control. Here we examine electrophysiological changes in two novel non-auditory areas implicated in tinnitus and hyperacusis: the caudal pontine reticular nucleus (PnC), involved in arousal, and the paraflocculus lobe of the cerebellum (PFL), implicated in head-eye coordination and gating tinnitus and we measure the changes in corticosterone stress hormone levels. Using the salicylate-induced model of tinnitus and hyperacusis, we found that long-latency (>10 ms) sound-evoked response components in both the brain regions were significantly enhanced after salicylate administration, while the short-latency responses were reduced, likely reflecting cochlear hearing loss. These results are consistent with the central gain model of tinnitus and hyperacusis, which proposes that these disorders arise from the amplification of neural activity in central auditory pathway plus other regions linked to arousal, emotion, tinnitus gating and motor control. Finally, we demonstrate that salicylate results in an increase in corticosterone level in a dose-dependent manner consistent with the notion that stress may interact with hearing loss in tinnitus and hyperacusis development. This increased stress response has the potential to have wide-ranging effects on the central nervous system and may therefore contribute to brain-wide changes in neural activity.

Noradrenaline from Locus Coeruleus Neurons Acts on Pedunculo-Pontine Neurons to Prevent REM Sleep and Induces Its Loss-Associated Effects in Rats.

Normally, rapid eye movement sleep (REMS) does not appear during waking or non-REMS. Isolated, independent studies showed that elevated noradrenaline (NA) levels inhibit REMS and induce REMS loss-associated cytomolecular, cytomorphological, psychosomatic changes and associated symptoms. However, the source of NA and its target in the brain for REMS regulation and function in health and diseases remained to be confirmed in vivo. Using tyrosine hydroxylase (TH)-siRNA and virus-coated TH-shRNA in normal freely moving rats, we downregulated NA synthesis in locus coeruleus (LC) REM-OFF neurons in vivo. These TH-downregulated rats showed increased REMS, which was prevented by infusing NA into the pedunculo-pontine tegmentum (PPT), the site of REM-ON neurons, normal REMS returned after recovery. Moreover, unlike normal or control-siRNA- or shRNA-injected rats, upon REMS deprivation (REMSD) TH-downregulated rat brains did not show elevated Na-K ATPase (molecular changes) expression and activity. To the best of our knowledge, these are the first in vivo findings in an animal model confirming that NA from the LC REM-OFF neurons (1) acts on the PPT REM-ON neurons to prevent appearance of REMS, and (2) are responsible for inducing REMSD-associated molecular changes and symptoms. These observations clearly show neuro-physio-chemical mechanism of why normally REMS does not appear during waking. Also, that LC neurons are the primary source of NA, which in turn causes some, if not many, REMSD-associated symptoms and behavioral changes. The findings are proof-of-principle for the first time and hold potential to be exploited for confirmation toward treating REMS disorder and amelioration of REMS loss-associated symptoms in patients.

A quantitative study of intracranial hypotensive syndrome by magnetic resonance.

OBJECTIVES: The study aims to investigate the magnetic resonance imaging (MRI) findings of intracranial hypotension syndrome (IHS) and the change of quantitative indicators, so as to yield a deeper understanding of the disease. PATIENTS AND METHODS: The clinical data and MRI findings of 26 cases of IHS which were confirmed by lumbar puncture were retrospectively analyzed. Two physicians evaluated the MRI findings including thickening and enhancement of dural, pituitary enlargement, subdural effusion (hematocele), venous engorgement and brain sagging, and measured the quantitative indicators including mamillopontine distance and pontomesencephalic angle. The consistency between the two results of the physicians was assessed by Kappa consistency test. The differences of mamillopontine distance and pontomesencephalic angle between the patient group and the control group were determined by paired t-test. The diagnostic efficiency of mamillopontine distance and pontomesencephalic angle was assessed by area under the ROC curve, and their best diagnostic thresholds were also determined, respectively. Age- and sex-matched healthy volunteers controls (n=26) were recruited and served as the control group. RESULTS: All of the 26 patients suffered from the characterized by orthostatic headache of IHS. The clinical evaluations of dural thickening and enhancement, pituitary enlargement, subdural effusion (hematocele), venous engorgement by the two physicians showed excellent agreements (κ=0.808, 1 and 0.906, P<0.01), and the clinical evaluations of brain sagging showed medium agreements (κ=0.606, P<0.01). The mamillopontine distance and pontomesencephalic angle of the patient group were 5.4 ± 1.6mm and 47.8 ± 8.7°, respectively, which were obviously less than those of the control group (6.9 ± 1.1mm and 61.0 ± 6.1°, respectively), and the differences were statistically significant (t=-4.563, P<0.01; t=-.329, P<0.01). The area under ROC curve of mamillopontine distance and pontomesencephalic angle were 0.774 and 0.908, respectively, and the diagnostic value of pontomesencephalic angle was higher than that of the mamillopontine distance. The sensitivity and specificity were 73.1% and 73.1%, respectively, when diagnostic threshold of mamillopontine distance was 6.4mm. The sensitivity and specificity were 76.9% and 96.2%, when diagnostic threshold of pontomesencephalic angle was 51.7°. CONCLUSION: The MRI findings presented characteristic features of IHS. The quantitative indicators including mamillopontine distance and pontomesencephalic angle were helpful for clinical diagnosis of subjective findings of IHS.

Saccadic Palsy following Cardiac Surgery: Possible Role of Perineuronal Nets.

OBJECTIVE: Perineuronal nets (PN) form a specialized extracellular matrix around certain highly active neurons within the central nervous system and may help to stabilize synaptic contacts, promote local ion homeostasis, or play a protective role. Within the ocular motor system, excitatory burst neurons and omnipause neurons are highly active cells that generate rapid eye movements - saccades; both groups of neurons contain the calcium-binding protein parvalbumin and are ensheathed by PN. Experimental lesions of excitatory burst neurons and omnipause neurons cause slowing or complete loss of saccades. Selective palsy of saccades in humans is reported following cardiac surgery, but such cases have shown normal brainstem neuroimaging, with only one clinicopathological study that demonstrated paramedian pontine infarction. Our objective was to test the hypothesis that lesions of PN surrounding these brainstem saccade-related neurons may cause saccadic palsy. METHODS: Together with four controls we studied the brain of a patient who had developed a permanent selective saccadic palsy following cardiac surgery and died several years later. Sections of formalin-fixed paraffin-embedded brainstem blocks were applied to double-immunoperoxidase staining of parvalbumin and three different components of PN. Triple immunofluorescence labeling for all PN components served as internal controls. Combined immunostaining of parvalbumin and synaptophysin revealed the presence of synapses. RESULTS: Excitatory burst neurons and omnipause neurons were preserved and still received synaptic input, but their surrounding PN showed severe loss or fragmentation. INTERPRETATION: Our findings support current models and experimental studies of the brainstem saccade-generating neurons and indicate that damage to PN may permanently impair the function of these neurons that the PN ensheathe. How a postulated hypoxic mechanism could selectively damage the PN remains unclear. We propose that the well-studied saccadic eye movement system provides an accessible model to evaluate the role of PN in health and disease.

Trigeminal root entry zone involvement in neuromyelitis optica and multiple sclerosis.

Trigeminal root entry zone abnormality on brain magnetic resonance imaging has been frequently reported in multiple sclerosis patients, but it has not been investigated in neuromyelitis optica patients. Brain magnetic resonance imaging of 128 consecutive multiple sclerosis patients and 46 neuromyelitis optica patients was evaluated. Trigeminal root entry zone abnormality was present in 11 (8.6%) of the multiple sclerosis patients and two (4.3%) of the neuromyelitis optica patients. The pontine trigeminal root entry zone may be involved in both multiple sclerosis and neuromyelitis optica.

Recovery of injured lower portion of the ascending reticular activating system in a patient with traumatic brain injury.

The authors report on a patient with traumatic brain injury who showed recovery of an injured lower portion of the ascending reticular activating system (ARAS) between the pontine reticular formation and the thalamus. A 57-yr-old male patient experienced head trauma. After 4 mos from onset, he exhibited impaired alertness, with a score of 7 on the Glasgow Coma Scale. At 40 mos after onset, the patient had a full Glasgow Coma Scale score of 15. The lower portion of the ARAS was reconstructed using the probabilistic tractography method. On 4-mo diffusion tensor tractography, the fractional anisotropy and the tract volume of the lower portion of the right ARAS were lower by more than 2 SDs of those of control subjects. By contrast, on 40-mo diffusion tensor tractography, the fractional anisotropy and the tract volume values of the lower portion of the right ARAS were within 2 SDs of those of the control subjects. The increment fractional anisotropy and the FV value of the lower portion of the right ARAS on 40-mo diffusion tensor tractography indicated recovery of the injured lower ARAS. As a result, recovery of an injured lower portion of the ARAS in a patient with traumatic brain injury was demonstrated.