Parents and caregivers should learn about autism spectrum disorder and its effects on their children. They should also learn how this disorder affects the entire family. It’s for this reason that researchers focus on research topics in autism that educate parents and caregivers about taking care of autistic children Mar 16, · These patients often present with cognitive impairment in memory, behavior, language, social functioning and often autism [1,2,4]. Joubert syndrome It is a rare autosomal recessive disorder associated with varying degrees of vermian dysplasia and lack of decussation of fibres in the superior cerebellar peduncles and pyramidal tracts Sep 25, · Autism Spectrum Disorders (ASDs) are a group of developmental disabilities that can cause significant social, communication and behavioral challenges. CDC is working to find out how many children have ASDs, discover the risk factors, and raise awareness of the signs
20 Great Scholarships for Students on the Autism Spectrum
Try out PMC Labs and tell us essay autism spectrum disorder you think. Learn More. The cerebellum is a crucial structure of hindbrain which helps in maintaining motor tone, posture, gait and also coordinates skilled voluntary movements including eye movements.
Cerebellar abnormalities have different spectrum, presenting symptoms and prognosis as compared to supratentorial structures and brainstem. This article intends to review the various pathological processes involving the cerebellum along with their imaging features on MR, which are must to know for all radiologists, neurologists and neurosurgeons for their prompt diagnosis and management.
Three pairs of dense fibre bundles Superior, middle and inferior cerebellar peduncles connect cerebellum with the brainstem [ 1 ].
There are certain pathologies unique to the cerebellum and it can also be involved by some nonspecific diseases that affect other areas of brain as well. These abnormalities are being identified with increasing frequency because of high resolution of infratentorial structures with MR imaging [ 2 ]. This article intends to review the various pathological processes involving the cerebellum along with their imaging features.
They may or may not be associated with involvement of other structures like pons, essay autism spectrum disorder, corpus callosum and cerebral hemispheres [ 1 ]. The important ones are discussed below. It is a sporadic disorder which occurs due to chromosomal abnormalities or single gene disorder or teratogen exposure resulting in developmental arrest of hindbrain formation. It consists of a group of anomalies in which there is cerebellar vermis hypoplasia and cystic dilatation of the fourth ventricle, which can be well appreciated on MR.
Dandy-Walker malformation which forms the most severe end of the spectrum can be differentiated from the Dandy-Walker variant Figure 1 by the presence of enlarged posterior fossa, elevation of tentorium and torcula herophilli, absent vermis in contrast to hypoplastic vermis in Dandy-walker variant.
The essay autism spectrum disorder hemispheres can be hypoplastic as well. The various associations are: nervous system malformations neuronal migrational anomalies and agenesis of corpus callosum and extracranial anomalies cardiac anomalies, skeletal dysplasias. Early diagnosis and management with ventriculoperitoneal or cystoperitoneal shunting is essential for improved survival in these patients [ 1 ]. Mega cistern magna and arachnoid cyst constitute the major differentials on imaging.
Mega cisterna magna can be differentiated by the presence of normal cerebellar vermis and hemispheres. Arachnoid cyst mimicks mega cisterna magna radiologically, but it causes mass effect on cerebellum, essay autism spectrum disorder ventricle and sometimes scalloping of inner cortex of occipital bone.
However, the exact differentiation between the two is possible with ventriculogram or cisternogram to show the communication of mega cisterna magna with the perimedullary subarachnoid space [ 3 ]. It was previously categorized as chiari4 malformation, but this term is obsolete now.
It refers to generalized hypoplasia of cerebellar hemispheres and vermis with no associated cyst or essay autism spectrum disorder of the posterior fossa.
It may be unilateral or bilateral. The etiological factors include exposure to drugs such as phenytoin, infection with cytomegalovirus, ionizing radiation and genetic defects trisomies 21,18 and These patients often present with cognitive impairment in memory, behavior, language, social functioning and often autism [ 124 ]. It is a rare autosomal recessive disorder associated with varying degrees of vermian dysplasia and lack of decussation of fibres in the superior cerebellar peduncles and pyramidal tracts.
It is characterized clinically by neonatal breathing dysregulation, developmental delay, hypotonia, ataxia, nystagmus, intellectual disability and abnormal facies [ 5 ]. Axial non-contrast CT images of the brain showing dilated batwing-shaped fourth ventricle Ahypoplastic vermis A, essay autism spectrum disorder, B in addition to thickened and elongated superior cerebellar peduncles with deep interpeduncular fossa A, B giving molar-tooth appearance.
It is a congenital abnormality of the cerebellum with absent or small vermis along with the fusion of cerebellar hemispheres, cerebellar peduncles with or without dentate nuclei [ 12 ]. Other rare syndromes associated with hypoplastic vermis include Oro-facial-digital syndrome type4, COACH syndrome and Arima syndrome cerebro-oculo-hepato-renal syndrome [ 1 ].
It is focal area of disorganized architecture in cerebellar hemispheres. Although its pathogenesis is still unclear, it is seen in association with chromosomal trisomies, intrauterine infections and congenital muscular dystrophies.
Most common sites of involvement are the nodulus, flocculus and tonsils. The MR imaging features include folial essay autism spectrum disorder, irregular grey-white interface with defective, large, abnormal fissures, heterotopias and cortical cystic lesions in severe cases with no contrast enhancement [ 8 ], essay autism spectrum disorder.
It is also known as dysplastic cerebellar gangliocytoma and presents clinically with macrocephaly and seizures. It results from derangement of normal laminar cellular organization of cerebellum resulting in thickened folia.
It has a strong association with visceral hamartomas [ 2 ]. There is evidence of mass effect on the fourth ventricle. The approach to diagnose cerebellar malformations is well illustrated in Supplement Figure 1. These are common hindbrain malformations associated with the caudal displacement of the cerebellum and the brainstem [ 1 ]. Chiari 1 is the commonest out of all and is characterized by herniation of peg like cerebellar tonsils more than 5 mm below the foramen magnum.
Syringohydromyelia is a common association. It is often asymptomatic or patients present in early adolescence with ataxia, neck pain and headache [ 9 ]. Chiari 2 consists of caudal displacement of cerebellar vermis, medulla and fourth ventricle through the foramen magnum and often associated with spina bifida and lumbosacral myelomeningocele [ 9essay autism spectrum disorder, 10 ] Figure 4.
Clinical symptoms depend on the age and range from myelomeningocele, cranial nerve palsies in the neonatal period to features of raised intracranial pressure during childhood and scoliosis in adults. A, B One and a half year old male child with chiari-2 malformation.
Sagittal T2 weighted images essay autism spectrum disorder the cervicodorsal spine including craniocervical junction essay autism spectrum disorder evidence of essay autism spectrum disorder displacement of the cerebellar vermis and medulla with spina bifida and meningomyelocele in the lower dorsal spine, essay autism spectrum disorder.
There is presence of syringohydromyelia as well in the dorsal spinal cord. Chiari 3 is quite uncommon and is characterized by combination of Chiari 2 malformation along with occipital or high cervical encephalocele [ 9 ].
Chiari 4 is obsolete term now and was previously used for severe cerebellar hypoplasia without its herniation [ 9 ]. Although cerebellar infarcts are more common than hemorrhage, they constitute only 1. Infarcts may occur in territories of any of the three arteries supplying the cerebellum namely: superior cerebellar artery SCAanterior inferior cerebellar artery AICAposterior inferior cerebellar artery PICA.
SCA supplies superior surface of cerebellar hemispheres upto great horizontal fissure, superior vermis, dentate nucleus and parts of midbrain. AICA perfuses anteroinferior surface of cerebellum with middle cerebellar peduncle, flocculus and inferolateral pons. Lastly, PICA supplies posteroinferior cerebellar hemispheres, inferior vermis, tonsils and lower medulla. Axial FLAIR sequence A showing hyperintensity involving bilateral posterior inferior cerebellar hemispheres corresponding to territory of posterior inferior cerebellar artery which shows acute diffusion restriction on diffusion weighted sequence B.
The most common etiological factor is uncontrolled hypertension, other causes being vascular malformations and neoplastic bleed. MR signal intensity characteristics depend on the stage of bleed.
Essay autism spectrum disorder carry a good prognosis if managed timely with evacuation and control of hydrocephalus, essay autism spectrum disorder, which is essentially required in cases of bleeds larger than 3 cm in diameter or with evidence of brainstem compression.
Remote cerebellar hemorrhage is a rare entity seen in the clinical setting of prior intracranial surgery or supratentorial craniotomies and has self limiting course.
Although its exact pathogenesis is still not clear, nevertheless, male sex, perioperative hypertension and CSF loss, preoperative use of anticoagulants are essay autism spectrum disorder risk factors [ 12 ]. Acute cerebellitis acute cerebellar ataxia is a rare inflammatory disorder characterized by isolated inflammation of cerebellum which can be either infectious, post-infectious or post-vaccination. The usual etiological factor being viral agents which include Varicella zoster, Epstein barr, measles, mumps, rubella, herpes simplex and coxsackie viruses.
It is more common in children, who present with acute onset of ataxia, essay autism spectrum disorder and dysarthria. Neuroimaging is usually normal and recovery often occurs over weeks, except in severe cases, in which there are features of raised intracranial pressure, essay autism spectrum disorder, hydrocephalus and brain herniation.
These cases also show positive findings on MR. The most common findings are diffuse swelling of bilateral cerebellar hemispheres involving both grey and white matter with T2 hyperintensities, mild diffusion restriction and contrast enhancement in the involved cerebellar cortex and leptomeninges Figure 6.
Unilateral involvement of cerebellum is uncommon and involvement of vermis and cerebellar peduncles is variable [ 13 ]. Axial FLAIR sequence A of MRI of the brain showing diffuse hyperintensities involving both cerebellar hemispheres with compression of fourth ventricle leading to obstructive hydrocephalus.
Parasagittal T2 weighted sequence B showing hyperintensities involving grey matter of cerebellar hemisphere with compressed fourth ventricle and tonsillar herniation. Axial contrast enhanced T1 weighted MR C showing diffuse leptomeningeal enhancement in bilateral cerebellum and axial diffusion weighted sequence D showing restricted diffusion in the same location. Parenchymal granulomas like tuberculomas, neurocysticercosis can also occur in the cerebellum as in other areas of the brain.
Essay autism spectrum disorder cerebellar abnormalities due to various inborn errors of metabolism can be divided into four groups namely: cerebellar hypoplasia in adenylsuccinase deficiencycerebellar atrophy, patchy or diffuse white matter abnormalities and involvement of dentate nuclei and cerebellar cortex [ 14 ]. Cerebellar atrophy can be differentiated from cerebellar hypoplasia discussed earlier by the presence of enlarged fissures in comparison to normal foliae secondary to loss of tissue in the former, but differentiation can be difficult at times or atrophy can be superimposed on hypoplasia in congenital disorder of glycosylation.
Atrophy can be due to a number of toxic causes like alcoholic cerebellar degeneration, drugs like phenytoin along with genetic neurodegenerative disorders discussed later [ 1415 ]. Symmetric involvement of dentate nuclei is seen in metabolic disorders like leigh disease, maple syrup urine disease also involves cerebellar white matterwernicke encephalopathy, and toxic causes like metronidazole induced essay autism spectrum disorder Figure 7methyl bromide intoxication or some organic solvents.
It is seen as hyperintensity on T2 weighted and FLAIR sequence with or without diffusion restriction [ 16 ]. The cerebellar cortex involvement is a feature of infantile neuroaxonal dystrophy [ 1415 ]. Axial FLAIR A and coronal T2 B sequence of MRI of the brain showing symmetric hyperintensities involving bilateral dentate nuclei of the cerebellum.
Axial diffusion weighted sequence C showing mild diffusion restriction in bilateral dentate nuclei. The inherited degenerations comprise a complex group of chronic disorders characterized by progressive ataxia and dysarthria. Familiarity with these entities and their imaging features is helpful for the differential diagnosis of ataxias of uncertain clinical type. It results from a defective gene located on chromosome 11q Essay autism spectrum disorder shows marked cerebellar atrophy involving both vermis and hemispheres.
Additionally, low signal intensity foci can be seen on T2 gradient echo images through out the brain representing capillary telangiectasias. Sometimes hemorrhages can be seen due to rupture of telangiectatic vessels. Wallis et al, essay autism spectrum disorder. reported increased choline signal in the cerebellum in these patients which can be a helpful differentiating feature from other forms of ataxias essay autism spectrum disorder 17 ]. It is the most common inherited progressive ataxia with autosomal recessive inheritance, which results due to repetition of unstable GAA trinucleotide in chromosome 9q.
In addition, there is loss of myelinated fibres and gliosis in the posterior and lateral columns of the cervical spinal cord. MRI shows thinning and intramedullary signal changes in the cervical spinal cord. The other significant finding which correlates with essay autism spectrum disorder degree of neurological deficits is atrophy of the peridentate cerebellum and superior cerebellar peduncles. Moreover, there is atrophy of the central portion of the medulla and midbrain, dorsal part of upper pons and optic chiasma [ 1819 ].
Olivopontocerebellar atrophy also known as multiple system atrophy-c type : It is a neurodegenerative disorder resulting from abnormalities of alpha-synuclein metabolism resulting in intracellular deposition both in neurons and oligodendroglia. Presentation is with ataxia and bulbar dysfunction and MR is the imaging modality of choice. On MRI, gross atrophy and T2 hyperintensities are seen in pons, middle cerebellar peduncles and cerebellum with hot cross bun sign in pons selective involvement of pontocerebellar tracts leads to formation of a cross on T2 weighted axial images through the pons [ 20 ] Figure 8.
Axial T2 weighted image A of the brain showing diffuse atrophy of the cerebellum and pons with hot cross bun sign in pons. Axial FLAIR sequence B showing hyperintensity in bilateral middle cerebellar peduncles with pontocerebellar atrophy, essay autism spectrum disorder.
What is autism spectrum disorder? - Mental health - NCLEX-RN - Khan Academy
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Autism spectrum disorders are not rare; many primary care pediatricians care for several children with autism spectrum disorders. Pediatricians play an important role in early recognition of autism spectrum disorders, because they usually are the first point of contact for parents. Parents are now much more aware of the early signs of autism spectrum disorders because Sep 25, · Autism Spectrum Disorders (ASDs) are a group of developmental disabilities that can cause significant social, communication and behavioral challenges. CDC is working to find out how many children have ASDs, discover the risk factors, and raise awareness of the signs Autism Speaks is dedicated to promoting solutions, across the spectrum and throughout the life span, for the needs of individuals with autism and families
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