Cerebellar Infarction: Unusual Manifestation with Facial Palsy, Focal Seizures, and Secondary Generalization

A Closer Look at a Small Brain: Transnuchal Ultrasound Facilitates High-Resolution Imaging of the Cerebellum in Preterm Infants

PURPOSE

 Very preterm infants are at risk for cerebellar injury and impaired cerebellar growth with adverse neurodevelopmental outcome. Ultrasound through the mastoid fontanel (MF) with a curved-array or sector probe is the most established method for the sonographic examination of the cerebellum. The goal of our study was to examine the validity of transnuchal ultrasound through the foramen occipitale magnum (FOM) with a linear probe for monitoring postnatal cerebellar growth.

METHODS

 Retrospective analysis of routine ultrasound scans through FOM and MF in 105 preterm infants born between 23 and 36 weeks of gestation with a birthweight of less than 1500 g.

RESULTS

 Diameters of the cerebellar hemispheres obtained through the two acoustic windows mastoid fontanel and foramen occipitale magnum showed high correlations (r's = 0.981 and 0.983, p's < 0.001). Corrected gestational age was significantly associated with transverse cerebellar diameter (TCD) on the first scan (r = 0.908, p < 0.001) as well as postnatal cerebellar growth (r = 0.920, p < 0.001). Postnatal growth was slightly decreased resulting in cerebellar growth restriction on serial scans. Both associations exceeded the calculated ratio of TCD to head circumference (r = 0.657, p < 0.001) and TCD to biparietal diameter with gestational age (r = 0.705, p < 0.001).

CONCLUSION

 Transnuchal ultrasound is feasible for examination of the preterm cerebellum and improves image quality compared to scans through the MF with higher resolution at a very short distance. Monitoring cerebellar growth during early postnatal life via transnuchal ultrasound can help to identify children at high risk for neurodevelopmental impairment.

Cerebellum and Prematurity: A Complex Interplay Between Disruptive and Dysmaturational Events

The cerebellum plays a critical regulatory role in motor coordination, cognition, behavior, language, memory, and learning, hence overseeing a multiplicity of functions. Cerebellar development begins during early embryonic development, lasting until the first postnatal years. Particularly, the greatest increase of its volume occurs during the third trimester of pregnancy, which represents a critical period for cerebellar maturation. Preterm birth and all the related prenatal and perinatal contingencies may determine both dysmaturative and lesional events, potentially involving the developing cerebellum, and contributing to the constellation of the neuropsychiatric outcomes with several implications in setting-up clinical follow-up and early intervention.

Possible contribution of cerebellar disinhibition in epilepsy

OBJECTIVE

We hypothesize that loss of inhibition from the cerebellum can lead to cortical activation and seizures.

BACKGROUND

The traditional model for development of seizures purports that the source of seizures is increased electrical activity originating from cerebral cortical neurons. Studies have shown a decrease in inhibition results in a shift of cortical activity to a hyperexcitable state, which may lead to seizures. Interestingly, a 1978 study suggested the term "disorder of disinhibition" as a way to describe epilepsy from studies of chronic cerebellar stimulation.

DESIGN/METHODS

Cases and experimental studies in which cerebellar lesions have been implicated in the development of seizures were reviewed. Cases in which cerebellar inhibition has been targeted in the treatment of seizures were also included. Twenty-six studies and case reports are presented for this report.

RESULTS

The cases show cerebellar lesions can lead to cortical epileptiform activity. Purkinje cell loss is linked to the occurrence of seizures in animals. The majority of patients with cerebellar lesions were seizure free after complete resection, while less than half of patients were seizure free after partial resection. Novel treatments using deep-brain stimulation targeting cerebellar structures demonstrated therapeutic benefits for seizures.

CONCLUSIONS

Although pathophysiology is not well-understood, the cerebellum likely plays an inherent role in inhibiting aberrant cortical epileptogenesis. Cerebellar lesions may cause seizures due to loss of the inhibition of cortical areas or through intrinsic epileptic activity. Treatments enhancing cerebellar stimulation have shown therapeutic benefits in treating seizures, which could potentially provide another avenue for treatment.

Neonatal Cerebellar Hemorrhage and Facial Nerve Palsy: An Unusual Association

Cerebellar hemorrhage is rare in term newborns and is most often seen after traumatic birth. Lifelong sequelae include motor and cognitive impairment. We report the uncommon case of a late preterm infant born by spontaneous delivery who showed right peripheral facial palsy at 24 hours of life. Cranial ultrasound showed lateral ventricles dilatation and a diffuse hyperechoic round lesion in the right cerebellar hemisphere. The computed tomography scan confirmed a hemorrhagic lesion in the right cerebellar hemisphere and in the vermis with midline shift and intraventricular bleeding. Ommaya reservoir was inserted and used for a few days. The facial palsy gradually recovered to a complete remission after 6 weeks. Follow-up examinations at 12 and 18 months evidenced infant's delayed motor function, hyperreflexia, tremors, and speech delay.

Perinatal stroke syndromes: Similarities and diversities in aetiology, outcome and management

With a birth-prevalence of 37-67/100,000 (mostly term-born), perinatal stroke encompasses distinct disease-states with diverse causality, mechanism, time of onset, mode of presentation and outcome. Neonatal primary haemorrhagic stroke and ischemic events (also divided into neonatal arterial ischemic stroke and neonatal cerebral sinus venous thrombosis) that manifest soon after birth are distinguished from presumed perinatal - ischemic or haemorrhagic - stroke. Signs of the latter become apparent only beyond the neonatal period, most often with motor asymmetry or milestones delay, and occasionally with seizures. Acute or remote MRI defines the type of stroke and is useful for prognosis. Acute care relies on homeostatic maintenance. Seizures are often self-limited and anticonvulsant agents might be discontinued before discharge. Prolonged anticoagulation for a few weeks is an option in some cases of sinovenous thrombosis. Although the risk of severe impairment is low, many children develop mild to moderate multimodal developmental issues that require a multidisciplinary approach.

Cerebellar motor syndrome from children to the elderly

More than a century after the description of its cardinal components, the cerebellar motor syndrome (CMS) remains a cornerstone of daily clinical ataxiology, in both children and adults. Anatomically, motor cerebellum involves lobules I-V, VI, and VIII. CMS is typically associated with errors in the metrics of voluntary movements and a lack of coordination. Symptoms and motor signs consist of speech deficits, impairments of limb movements, and abnormalities of posture/gait. Ataxic dysarthria has a typical scanning (explosive with staccato) feature, voice has a nasal character, and speech is slurred. Cerebellar mutism is most common in children and occurs after resection of a large midline cerebellar tumor. Ataxia of limbs includes at various degrees dysmetria (hypermetria: overshoot, hypometria: undershoot), dysdiadochokinesia, cerebellar tremor (action tremor, postural tremor, kinetic tremor, some forms of orthostatic tremor), isometrataxia, disorders of muscle tone (both hypotonia and cerebellar fits), and impaired check and rebound. Handwriting is irregular and some patients exhibit megalographia. Cerebellar patients show an increased body sway with a broad-based stance (ataxia of stance). Gait is irregular and staggering. Delayed learning of complex motor skills may be a prominent feature in children. CMS is currently explained by the inability of the cerebellum to handle feedback signals during slow movements and to create, store, select, and update internal models during fast movements. The cerebellum is embedded in large-scale brain networks and is essential to perform accurate motor predictions related to body dynamics and environmental stimuli. Overall, the observations in children and adults exhibiting a CMS fit with the hypothesis that the cerebellum contains neural representations reproducing the dynamic properties of body, and generates and calibrates sensorimotor predictions. Therapies aiming at a reinforcement or restoration of internal models should be implemented to cancel CMS in cerebellar ataxias. The developmental trajectory of the cerebellum, the immature motor behavior in children, and the networks implicated in CMS need to be taken into account.