| Benedikt syndrome | |
|---|---|
| Other names | Paramedian midbrain syndrome |
| Specialty | Neurology  |
Benedikt syndrome, also called Benedikt's syndrome or paramedian midbrain syndrome, is a rare type of posterior circulation stroke of the brain, with a range of neurological symptoms affecting the midbrain, cerebellum and other related structures.
It is characterized by the presence of
Neuroanatomical structures affected include the oculomotor nucleus, red nucleus, corticospinal tracts and superior cerebellar peduncle decussation.
It has a similar cause, morphology, signs and symptoms to Weber's syndrome; the main difference between the two being that Weber's is more associated with hemiplegia (i.e. paralysis), and Benedikt's with ataxia (i.e. disturbed coordination of movements).
While both Benedikt's and Claude's syndrome share some similarities, they can be differentiated based on the type of movement impairment they cause. Benedikt's syndrome is characterized by more prominent tremors and involuntary, writhing movements (choreoathetosis), whereas Claude's syndrome is primarily marked by difficulties with coordination and balance (ataxia).[ citation needed ]
Benedikt syndrome is caused by a lesion (infarction, hemorrhage, tumor, or tuberculosis) in the tegmentum of the midbrain and cerebellum. Specifically, the median zone is impaired. It can result from occlusion of the posterior cerebral artery [1] or paramedian penetrating branches of the basilar artery. [2]
Deep brain stimulation may provide relief from some symptoms of Benedikt syndrome, particularly the tremors associated with the disorder. [3]
The oculomotor nerve, also known as the third cranial nerve, cranial nerve III, or simply CN III, is a cranial nerve that enters the orbit through the superior orbital fissure and innervates extraocular muscles that enable most movements of the eye and that raise the eyelid. The nerve also contains fibers that innervate the intrinsic eye muscles that enable pupillary constriction and accommodation. The oculomotor nerve is derived from the basal plate of the embryonic midbrain. Cranial nerves IV and VI also participate in control of eye movement.
Lateral medullary syndrome is a neurological disorder causing a range of symptoms due to ischemia in the lateral part of the medulla oblongata in the brainstem. The ischemia is a result of a blockage most commonly in the vertebral artery or the posterior inferior cerebellar artery. Lateral medullary syndrome is also called Wallenberg's syndrome, posterior inferior cerebellar artery (PICA) syndrome and vertebral artery syndrome.
The medial longitudinal fasciculus (MLF) is an area of crossed over tracts, on each side of the brainstem. These bundles of axons are situated near the midline of the brainstem. They are made up of both ascending and descending fibers that arise from a number of sources and terminate in different areas, including the superior colliculus, the vestibular nuclei, and the cerebellum. It contains the interstitial nucleus of Cajal, responsible for oculomotor control, head posture, and vertical eye movement.
Medial medullary syndrome, also known as inferior alternating syndrome, hypoglossal alternating hemiplegia, lower alternating hemiplegia, or Dejerine syndrome, is a type of alternating hemiplegia characterized by a set of clinical features resulting from occlusion of the anterior spinal artery. This results in the infarction of medial part of the medulla oblongata.
Brain herniation is a potentially deadly side effect of very high pressure within the skull that occurs when a part of the brain is squeezed across structures within the skull. The brain can shift across such structures as the falx cerebri, the tentorium cerebelli, and even through the foramen magnum. Herniation can be caused by a number of factors that cause a mass effect and increase intracranial pressure (ICP): these include traumatic brain injury, intracranial hemorrhage, or brain tumor.
The posterior cerebral artery (PCA) is one of a pair of cerebral arteries that supply oxygenated blood to the occipital lobe, part of the back of the human brain. The two arteries originate from the distal end of the basilar artery, where it bifurcates into the left and right posterior cerebral arteries. These anastomose with the middle cerebral arteries and internal carotid arteries via the posterior communicating arteries.
The flocculus is a small lobe of the cerebellum at the posterior border of the middle cerebellar peduncle anterior to the biventer lobule. Like other parts of the cerebellum, the flocculus is involved in motor control. It is an essential part of the vestibulo-ocular reflex, and aids in the learning of basic motor skills in the brain.
Cerebellar ataxia is a form of ataxia originating in the cerebellum. Non-progressive congenital ataxia (NPCA) is a classical presentation of cerebral ataxias.
The anterior inferior cerebellar artery (AICA) is one of three pairs of arteries that supplies blood to the cerebellum.
The superior cerebellar artery (SCA) is an artery of the head. It arises near the end of the basilar artery. It is a branch of the basilar artery. It supplies parts of the cerebellum, the midbrain, and other nearby structures. It is the cause of trigeminal neuralgia in some patients.
Intention tremor is a dyskinetic disorder characterized by a broad, coarse, and low-frequency tremor evident during deliberate and visually-guided movement. An intention tremor is usually perpendicular to the direction of movement. When experiencing an intention tremor, one often overshoots or undershoots one's target, a condition known as dysmetria. Intention tremor is the result of dysfunction of the cerebellum, particularly on the same side as the tremor in the lateral zone, which controls visually guided movements. Depending on the location of cerebellar damage, these tremors can be either unilateral or bilateral.
Weber's syndrome, also known as midbrain stroke syndrome or superior alternating hemiplegia, is a form of stroke that affects the medial portion of the midbrain. It involves oculomotor fascicles in the interpeduncular cisterns and cerebral peduncle so it characterizes the presence of an ipsilateral lower motor neuron type oculomotor nerve palsy and contralateral hemiparesis or hemiplegia.
Posterior cerebral artery syndrome is a condition whereby the blood supply from the posterior cerebral artery (PCA) is restricted, leading to a reduction of the function of the portions of the brain supplied by that vessel: the occipital lobe, the inferomedial temporal lobe, a large portion of the thalamus, and the upper brainstem and midbrain.
Anterior cerebral artery syndrome is a condition whereby the blood supply from the anterior cerebral artery (ACA) is restricted, leading to a reduction of the function of the portions of the brain supplied by that vessel: the medial aspects of the frontal and parietal lobes, basal ganglia, anterior fornix and anterior corpus callosum.
Posterior circulation infarct (POCI) is a type of cerebral infarction affecting the posterior circulation supplying one side of the brain.
A brainstem stroke syndrome falls under the broader category of stroke syndromes, or specific symptoms caused by vascular injury to an area of brain. As the brainstem contains numerous cranial nuclei and white matter tracts, a stroke in this area can have a number of unique symptoms depending on the particular blood vessel that was injured and the group of cranial nerves and tracts that are no longer perfused. Symptoms of a brainstem stroke frequently include sudden vertigo and ataxia, with or without weakness. Brainstem stroke can also cause diplopia, slurred speech and decreased level of consciousness. A more serious outcome is locked-in syndrome.
Claude's syndrome is a form of brainstem stroke syndrome characterized by the presence of an ipsilateral oculomotor nerve palsy, contralateral hemiparesis, contralateral ataxia, and contralateral hemiplegia of the lower face, tongue, and shoulder. Claude's syndrome affects oculomotor nerve, red nucleus and brachium conjunctivum.
Ataxic cerebral palsy is clinically in approximately 5–10% of all cases of cerebral palsy, making it the least frequent form of cerebral palsy diagnosed. Ataxic cerebral palsy is caused by damage to cerebellar structures, differentiating it from the other two forms of cerebral palsy, which are spastic cerebral palsy and dyskinetic cerebral palsy.
Cerebellar cognitive affective syndrome (CCAS), also called Schmahmann's syndrome is a condition that follows from lesions (damage) to the cerebellum of the brain. It refers to a constellation of deficits in the cognitive domains of executive function, spatial cognition, language, and affect resulting from damage to the cerebellum. Impairments of executive function include problems with planning, set-shifting, abstract reasoning, verbal fluency, and working memory, and there is often perseveration, distractibility and inattention. Language problems include dysprosodia, agrammatism and mild anomia. Deficits in spatial cognition produce visual–spatial disorganization and impaired visual–spatial memory. Personality changes manifest as blunting of affect or disinhibited and inappropriate behavior. These cognitive impairments result in an overall lowering of intellectual function. CCAS challenges the traditional view of the cerebellum being responsible solely for regulation of motor functions. It is now thought that the cerebellum is responsible for monitoring both motor and nonmotor functions. The nonmotor deficits described in CCAS are believed to be caused by dysfunction in cerebellar connections to the cerebral cortex and limbic system.
Raymond–Céstan syndrome is caused by blockage of the long circumferential branches of the basilar artery. It was described by Fulgence Raymond and Étienne Jacques Marie Raymond Céstan. Along with other related syndromes such as Millard–Gubler syndrome, Foville's syndrome, and Weber's syndrome, the description was instrumental in establishing important principles in brain-stem localization.