Neurological Glossary
Neurological terms are often complicated and difficult to understand. The following glossary defines a variety of terms to help you understand neurological terminology:
Echocardiogram
An ultrasound examination of the heart
Echolalia
The echoing or repetition of verbal utterances made by another person
Echopraxia
Imitative repetition of the movements
Edinger-Westphal nucleus
Accessory nucleus of each oculomotor nerve that supplies preganglionic parasympathetic fibers for pupillary constriction and lens accommodation; located in the midline between the extraocular oculomotor nerve nuclei
Efferent
Motor pathway proceeding from the CNS toward the peripheral end organs
Eidetic memory (photographic memory)
Ability to vividly recall visual images
Electroencephalogram (EEG)
Test that measures and records the electrical activity of the brain by using sensors (electrodes) attached to the head.
Electronic aids
Assistive devices
Eloquent cortex
Regions of the cerebral cortex responsible for motor
Embolism
The blockage of a blood vessel by an embolus'something previously circulating in the blood (such as a blood clot
Emotional liability
A state of emotional disinhibition
Encephalitis
Inflammation of the brain
Encephalocele
Failure of bone fusion in the posterior midline of the skull resulting in a bony cleft through which meninges and/or brain parenchyma protrude
Encephalomalacia
Focal softening of the brain in areas of tissue death following cerebral infarction
Encephalopathy
Meaning
Endomysium
Innermost layer of connective tissue that forms an interstitial layer around each individual muscle fibre
Endoneurium (epilemma)
Innermost layer of connective tissue of a peripheral nerve that forms an interstitial layer around each individual axon / Schwann cell unit
Enophthalmos
Recession of the eyeball within the orbit
Eosinophilic neuronal necrosis
Neuronal response to ischemia and hypoxia characterized by brightly eosinophilic (red) cytoplasm and nuclear shrinkage
Ependyma
Epithelial lining of the ventricles of the brain and the canal of the spinal cord
Ependymal cells
Type of glia consisting of cuboidal cells lining the adult ventricles and spinal canal
Ependymal true rosette
Halo of cells surrounding an empty lumen; fairly specific for
Ependymoma
WHO grade II primary CNS tumour of children (involving the 4th ventricle) and young adults (involving the spinal cord); characterized histologically by perivascular pseudorosettes
Ephaptic
Electrical conduction of a nerve impulse across a non-synaptic contact site between nerves and without the mediation of a neurotransmitter
Epilepsy
A neurological condition originating in the brain and involving abnormal electrical activity in the brain which causes seizures of varying degree
Epilepsy syndrome
Disorder defined by seizure type
Epineurium
Outermost layer of a peripheral nerve containing connective tissue and an anastomotic vascular network
Epiphyseal Plate
The layer of cartilage between the diaphysis and epiphysis
Epiphysis
A secondary centre of ossification
Epithalamus
Dorsal posterior subdivision of the diencephalon generally considered to include the habenula
Equinus
Abnormality of foot which prevents normal weight-bearing
Equilibrium Reaction
Balance reaction
Esotropia
An eye with strabismus that deviates inward
Essential tremor
Medium or high frequency (4-9 Hz) tremor that occurs with action or holding a sustained posture that typically affects the arms
Eversion
Turning the sole of the foot away from the median plane
Evoked potentials
Recordings of the nervous system's electrical response to the stimulation of specific sensory pathways
Excessive daytime sleepiness (hypersomnolence)
Subjective difficulty in staying awake and easily falling asleep when sedentary
Executive functions
Higher intellectual functions such as judgment
Exotropia
An eye with strabismus that deviates outward
Expanded Disability Status Scale (EDSS)
20-point scale
Extension
Straightening
Extensor plantar response
Extension of the great toe ('upgoing toe') with fanning of the other toes in response to application of a stimulus to the skin of the foot or leg; signifies a lesion of the corticospinal tract
Extensor posturing
Stereotyped posture occurring in coma in response to stimulation in which the arms and legs extend (hips and shoulders extend
Extensor response in the arm
Stereotyped posture occurring in coma in response to stimulation in which the upper extremity extends (shoulder extends
Extensor spasm
Manifestation of spasticity in which the legs involuntarily straighten into an extended position where they remain for several minutes
External
Outside
Extra-axial
Within the skull or vertebral column but outside of the brain or spinal cord
Extracranial-intracranial bypass
Surgery to restore blood flow to an area of brain tissue by re-routing a healthy artery in the scalp to the area of brain tissue affected by a blocked or narrowed artery
Extrapyramidal
Movement disorder not involving the corticospinal tracts; typically refers to basal ganglia or cerebellar disorders
Extrasylvian
Outside of the area surrounding the Sylvian fissure; often used synonymously with