ISTILAH NEUROLOGI abducens nerve (cranial nerve VI) motor nerve innervating the lateral rectus muscle, which abducts the eye; lesions of the nucleus, which is located in the dorsal pons, produce a horizontal gaze palsy; nerve fibers exit the ventromedial pons and because of their long course are vulnerable to damage by mass lesions/increasedintracranial pressure abduct move away from the saggittal plane of the body absence seizure (petit mal seizure) generalized seizure characterized by abrupt cessation of ongoing activity with a blank stare and lost or impaired consciousness lasting on average 10-20 seconds abulia loss of will, impulse, and decision-making ability acalculia "inability to calculate" or difficulty with arithmetic; may be the result of damage to the angular gyrusin the hemisphere dominant for speech and language acephalic migraine migraine variant consisting of the migraine aura without the headache; also known as migraine equivalent accommodation adjustment of the focal length of the lens of the eye in order to keep objects at varying distances in focus on the retina acrocephaly action potential see brachycephaly action potential rapid, transient, all-or-none nerve impulse initiated at the axon hillock; electrical signal by which the brain receives, analyzes, and conveys information action tremor tremor that appears during movement of the affected body part activities of daily living (ADLs) activities a person performs for self-care (feeding, grooming, bathing, dressing), work, homemaking, and leisure; ability to perform ADLs is often used as a measure of ability/disability activity limitations difficulties an individual may have in executing specific tasks or actions (e.g., walking independently). acute developing over minutes to hours; implies acute metabolic dysfunction (e.g., ischemia, seizure ) Acute Disseminated Encephalomyelitis (ADEM) acute, classically monophasic demyelinative disease of theCNS that may follow a viral syndrome or vaccination or no identifiable predisposing cause adduct move towards the saggittal plane of the body Adie’s syndrome association of Adie’s tonic pupil with absence of muscle stretch reflexes Adie’s tonic pupil irregularly dilated pupil exhibiting minimal or no reaction to light, slow reaction to accommodation, and hypersensitivity to pilocarpine; typically idiopathic and most often seen in young women adrenoleukodystrophy typically X-linked recessive demyelinative disease ± adrenal dysfunction due to accumulation of very long chain fatty acids afferent sensory pathway proceeding toward the CNS from the peripheral receptor organs afferent pupillary defect (Marcus-Gunn pupil) pupillary dilation in the eye with a pre-chiasmic optic pathway lesion (e.g., optic neuritis) in response to shining a light in the damaged eye after first shining it in the normal eye ageusia impaired sense of taste
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ISTILAH NEUROLOGI
abducens nerve (cranial nerve VI) motor nerve innervating the lateral rectus muscle,
which abducts the eye; lesions of the nucleus, which is located in the dorsal pons, produce a
horizontal gaze palsy; nerve fibers exit the ventromedial pons and because of their long course are
vulnerable to damage by mass lesions/increasedintracranial pressure
abduct move away from the saggittal plane of the body
absence seizure (petit mal seizure) generalized seizure characterized by abrupt cessation of
ongoing activity with a blank stare and lost or impaired consciousness lasting on average 10-20
seconds
abulia loss of will, impulse, and decision-making ability
acalculia "inability to calculate" or difficulty with arithmetic; may be the result of damage to
the angular gyrusin the hemisphere dominant for speech and language
acephalic migraine migraine variant consisting of the migraine aura without the headache; also
known as migraine equivalent accommodation adjustment of the focal length of the lens of the eye
in order to keep objects at varying distances in focus on the retina
acrocephaly action potential see brachycephaly
action potential rapid, transient, all-or-none nerve impulse initiated at the axon hillock; electrical
signal by which the brain receives, analyzes, and conveys information
action tremor tremor that appears during movement of the affected body part
activities of daily living (ADLs) activities a person performs for self-care (feeding, grooming,
bathing, dressing), work, homemaking, and leisure; ability to perform ADLs is often used as a
measure of ability/disability
activity limitations difficulties an individual may have in executing specific tasks or actions (e.g.,
walking independently).
acute developing over minutes to hours; implies acute metabolic dysfunction
perisylvian plexus referring to structures around the Sylvian fissure; includes Wernicke's area in
auditory association cortex and Broca's area in front of motor cortex
perimysium connective tissue sheath surrounding a bundle of muscle fibers
petit mal seizure see absence seizure
phonophobia abnormal intolerance to sound that commonly occurs in migraine and other
headaches
photophobia abnormal intolerance to light, usually associated with eye pain; characteristic
of meningeal irritation, migraine, optic nerve disease, and ocular or retinal disorders
physiologic tremor subtle low amplitude, high frequency tremor most easily observed in the hands
that is present in healthy persons and most prominent during posture and action
pia innermost layer of the meninges that is intimately applied to the surface of the
brain parenchyma and spinal cord and separated from the arachnoid by the subarachnoid space
Pick’s disease form of frontotemporal dementia characterized by a slowly progressive
deterioration of social skills and changes in personality in addition to impairment of intellect,
memory, and language; defined pathologically by Pick bodies (rounded tau-posiotive inclusions
similar to neurofibrillary tangles) and Pick cells (swollen or ballooned neurons) in a predominantly
frontal location
pincer grasp finger-thumb opposition
pineal midline body attached to the posterior part of the third ventricle and lying between
the superior colliculi, below the splenium of the corpus callosum; major site of melatonin
biosynthesis
pituitary apoplexy spontaneous hemorrhagic infarction of a typically large and
nonfunctioning pituitaryadenoma presenting with headache, nausea and vomiting, cranial nerve II,
III, IV, or VI palsies, altered mental status, and hypopituitarism
pituitary gland (hypophysis) endocrine organ lying ventral to the hypothalamus and optic
chiasm; includes an anterior glandular lobe made up of hormone-secreting cells and a posterior
neural lobe containing the terminals of neuropeptide-secreting, hypothalamic neurons
placing (stepping) response normal neonatal reflex consisting of elevating the foot and moving it
forward when its dorsal surface is touched; the infant will appear to attempt to stand or walk
plagiocephaly premature fusion of a unilateral coronal and/or lambdoid +/- sagittal suture
plantar response superficial (cutaneous) reflex elicited by applying a stimulus to the skin of the
foot or leg; flexion (curling down) of all toes (“downgoing toe”) is a normal response, while extension
of the great toe (“upgoing toe”) with fanning of the other toes is abnormal and signifies a lesion of
the corticospinal tract. Many methods of eliciting the plantar reflex have been described, including
the following:
Eponym Technique
Babinski
Stimulation of the plantar surface of the foot with a blunt point from the heel forward, crossing the metatarsal pad from the small to the great toe
ChaddockStimulation of the lateral aspect of the foot with a blunt point from the heel forward to the small toe
Oppenheim
Application of heavy pressure with the thumb and index finger to the anterior surface of the tibia with downward stroking from the infrapatellar region to the ankle
Gordon Squeezing or applying deep pressure to the calf muscles
Strümpell Forceful pressure on the anterior tibia
Moniz Forceful passive plantar flexion of the ankle
Gonda-Allen Downward snapping of the distal phalanx of the second or fourth toe
Stransky Gentle extension of the small toe laterally
Bing Application of pinprick to the dorsal surface of the great toe
plegia inability to activate any motor neurons; paralysis
polymyositis inflammatory muscle disease associated with primarily proximal limb weakness;
considered to be an autoimmune disease of disordered cellular immunity and often associated with
a specific collagen-vascular disease
polysomnogram continuous and simultaneous recording of multiple physiological variables during
sleep
pons middle aspect of the brainstem, lying between the midbrain rostrally and the medulla caudally
porencephaly cerebral hemispheric cyst that is usually the remnant of a destructive lesion
(e.g., stroke or infection) or is due to abnormal brain development
positive sharp wave spontaneous muscle activity seen on electromyography in association with
denervation or irritable myopathy consisting of long action potentials with initial positive (down)
wave followed by wide negative (up) wave
positive symptom exaggeration of a physiological phenomenon; implies abnormal excessive
(irritative”) discharges in gray matter or (e.g., seizure or hemifacial spasm) or chronic imbalance in
complex integrated motor pathways (e.g., chorea)
postdrome period following a migraine during which a person has impaired concentration, fatigue,
or irritability
posterior cerebral artery paired arteries that arise from the top of the basilar artery; supply blood
to the posterior areas of the brain, including the medial occipital lobes (visual cortex), the inferior
temporal lobes, andthalamus
posterior commissure one of the three major groups of commissural fibers that crosses the
midline of the epithalamus just dorsal to the point where the cerebral aqueduct opens into the
third ventricle
posterior communicating artery branch of the internal carotid artery that joins the middle
cerebral artery(anterior circulation) to the posterior cerebral artery (posterior circulation);
supplies thalamus, hypothalamus,optic chiasm, and mammillary bodies
posterior cord syndrome spinal cord injury syndrome associated with damage to the posterior
portion of the spinal cord resulting in bilateral loss of vibration /proprioception +/- bilateral weakness
below the level of the lesion
posterior fossa brainstem and cerebellum
posterior horn (dorsal horn) gray matter in the back of the spinal cord that receives sensory
information from the body through the dorsal root ganglia post-herpetic neuralgia condition
following an acute varicella zoster infection (shingles) characterized by persistent pain (3 or more
months) in the dermatomal distribution of the previous zoster rash
postural instability loss of ability to make postural adjustments in response to perturbations, i.e.,
defect in righting reflex; common in Parkinson disease
postural tremor tremor that occurs with the maintenance of a posture or position against gravity
posture ability to stand upright automatically against gravity; controlled by the vestibulospinal,
reticulospinal, and tectospinal pathways
Pott’s disease tuberculous involvement of the vertebral column with vertebral collapse
praxis ability to plan, time, sequence, and spatially organize skilled movements prefrontal
cortex corticalregion of the frontal lobe lying anterior to primary and premotor cortex; mediates
various executive functions, with the dorsolateral division involved in working memory processes,
planning, and decision making, and the ventromedial division involved in emotion and the
organization of appropriate social behavior
premotor cortex cortical region (Brodmann's area 6) in the posterior frontal lobe anterior to the
primary motorcortex involved in planning or programming of voluntary movements
primary progressive clinical course of multiple sclerosis characterized from the beginning by
progressive disease, with no plateaus or remissions, or an occasional plateau and very short-lived,
minor improvements
primary progressive aphasia progressive form of dementia characterized by global loss of
language abilities and initial preservation of other cognitive functions; pathologically, there may be
spongiform changes in teh frontal and temporal lobes rather than Alzheimer-like changes primitive
neuroepithelial tumor (PNET)tumor histologically similar to the medulloblastoma but located
outside the posterior fossa
prion proteinacious infectious agent responsible for various fatal brain diseases classified
as spongiform encephalopathy
prodrome premonitory phenomena occurring hours to days before headache onset
in migraine consisting of psychological, neurological, or constitutional symptoms
progressive multifocal leukoencephalopathy (PML) fatal demyelinating CNS disease of
immunocompromised patients caused by reactivation of the JC papovavirus
progressive supranuclear palsy (Steele-Richardson-Olszewski syndrome) Parkinson plus
syndromecharacterized by predominantly axial rigidity, akinesia, supranuclear ophthalmoplegia
(impairment of voluntary vertical gaze—downward more than upward), and pseudobulbar palsy
proprioception joint position sense
proptosis (exophthalmos) abnormal protrusion of the eyeball
prosencephalon see forebrain
prosody emotional content of language pseudoathetosis involuntary slow, writhing movements of a
limb (usually the hand or fingers) occurring when the eyes are closed due to
impaired proprioception. Unlike inathetosis, the movements are not present when the eyes are open
because visual feedback provides the necessary information to know where the limb is in space.
pseudobulbar affect condition in which episodes of laughing and/or crying occur with no apparent
precipitating event
pseudobulbar palsy syndrome characterized by dysarthria, dysphagia, dysphonia, impairment of
voluntary movements of tongue and facial muscles, and emotional lability; caused by diseases such
as multiple sclerosis, motor neuron disease, and stroke that affect the motor fibers traveling from
the cerebral cortex to the lowerbrainstem (i.e., corticobulbar tracts)
pseudorosette spoke-wheel arrangement of cells with tapered cellular processes surrounding a
blood vessel, creating a perivascular nuclear free zone; seen in most ependymomas and less
commonly in other CNS tumorsptosis eyelid droopiness
pupillary light response contraction of the pupil on exposure of the retina to light; dependent on
proper functioning of the optic and oculomotor nerves
putamen largest and most lateral component of the basal ganglia
pyramid prominent column of white matter on the ventromedial margin of
the medulla containing axons of the corticospinal tract
pyramidal tract see corticospinal tract
quad cane cane that has a broad base on four short “feet,” which provide extra stability
quadrantanopia loss of vision in either the upper or lower aspect of one hemifield (involving both
eyes)
quadrigeminal bodies two pairs of elevations on the dorsal surface of the midbrain; includes
the superior colliculi and inferior colliculi
quadriplegia (tetraplegia) paralysis of all four extremities rachischisis fissure of the spinal cord
resulting in exposure of the incompletely folded cord along the back
radiculopathy symptoms and signs associated with spinal nerve root compression
Ramsy-Hunt syndrome facial paralysis, hyperacusis, loss of taste, and vesicles on the eardrum,
external auditory meatus, or palate due to herpes zoster infection of the geniculate ganglion
raphe ridge of tissue
raphe nuclei nuclei located within the medial portion of the reticular formation in
the brainstem that secrete serotonin
Raymond syndrome ipsilateral lateral rectus palsy and contralateral hemiplegia sparing the face
due to aventral pontinelesion affecting the abducens nerve fascicles and corticospinal tract (but
sparing the facial nerve)
recurrent-remittent episodic attacks of symptoms with rapid recovery to normal health; implies
repeating episodes of a single process (e.g., transient ischemic attacks (TIA), seizures, migraine,
and multiple sclerosis)
red desaturation finding of dimmer perception of the color red in an eye affected by optic
nerve disease such as optic neuritis; sign of subtle asymmetry in optic nerve function since color
desaturation may occur despite normal visual acuity
red nucleus oval nucleus centrally placed in the upper midbrain reticular formation that receives
fibers from the deep cerebellar nuclei and cerebral cortex and projects to the cerebellum, brainstem,
spinal cord, and probably thalamus
relapsing-remitting clinical course of multiple sclerosis characterized by episodic attacks of
symptoms with recovery to normal health
REM behavior disorder disorder occurring during REM sleep in which the normal motor atonia is
partially or completely absent such that dreams can be acted out with punching, kicking, and
jumping out of bed
REM sleep (rapid eye movement sleep) sleep stage in which vivid dreaming occurs; identified
by the occurrence of rapid eye movements under closed eyelids, motor atonia, low
voltage EEG pattern, bursts of muscular twitching, irregular breathing, irregular heart rate, and
increased autonomic activity.
repetitive nerve stimulation nerve conduction study in which a brief series of shocks is applied to a
motor nerve before and after brief exercise of a muscle supplied by that nerve; useful for evaluating
disorders of neuromuscular transmission such as myasthenia gravis (decremental response see)
and Lambert Eaton myasthenic syndrome (incremental response seen).
restiform body see inferior cerebellar peduncle
resting tremor medium-frequency (3-6 Hz) tremor that occurs maximally with the affected body at
rest rather than with holding a sustained posture or making an intentional movement; common
in Parkinson disease
restless legs syndrome sleep disorder characterized by tingling, creepy-crawly, or aching
sensation in the legs and sometimes arms as well as motor restlessness that tends to occur at rest
(especially around the patient’s usual bedtime) and to be relieved temporarily by movement
reticular activating system (RAS) the activating mechanisms that lie in or near the central gray
matter of thediencephalon, midbrain, and rostral pons and are responsible for mediating
consciousness
reticular formation heterogeneous collection of neurons scattered throughout
the brainstem tegmentumthat either modulate forebrain and spinal cord activity or coordinate the
firing patterns of lower motor neuronsengaged in reflexive or stereotypical somatic motor and
visceral motor activities
reticulospinal tract descending pathway from the reticular formation of the brainstem to
spinal inter- and motor neurons that control anti-gravity posture and locomotion
retina light-sensitive neuronal layer lining the back of the eye that sends impulses through the optic
nerve that are translated into a visual image; part of the central nervous system retropulsion a
tendency to walk backward involuntarily that can occur in Parkinson disease
rhombencephalon hindbrain; includes the pons, cerebellum, and medulla
righting reflex ability to make postural adjustments in response to perturbations
rigidity increased resistance throughout the range of motion when passively moving a body part
due to co-contraction of agonist and antagonist muscles ("lead pipe")
ring-enhancement CT or MRI contrast enhancement surrounding a lesion that has blood-brain
barrierbreakdown, such as metastatic tumor or abscess
Romberg test inability to maintain upright posture when feet together and eyes closed; indicates
impairedproprioception
rooting reflex normal neonatal reflex consisting of turning the head towards a stimulus presented
to the side of the mouth, latching on, and sucking
Rosenthal fibers eosinophilic corkscrew or rod-shaped inclusions seen in
pilocytic astrocytoma rostral toward the head or nose
rostrocaudal literally “from the nose to the tail”; used to describe the sequence of symptoms
referable to progressively lower parts of the brainstem characteristic of transtentorial herniation
rubral tremor low-frequency (<4.5 Hz) tremor often of irregular, coarse rhythm that is present
during both rest and intentional movements and typically follows cerebellar outflow pathway lesions
Ruffini corpuscles thermoreceptors in the skin
saccade discrete, rapid conjugate eye movements from one object to another
saccular aneurysm spherical outpouching from one side of an artery that occurs at an arterial
bifurcation point and reflects weakness of all layers of the vessel wall
sagittal vertical plane passing through the standing body from front to back sagittal sulcus
(longitudinal fissure) long, deep, sagittally oriented cleft that separates the two cerebral
hemispheres on the dorsal midline
salivatory nuclei small nuclei in the pontine tegmentum that provide parasympathetic
preganglionic innervation to ganglia associated with the lacrimal and salivary glands to control
salivation and tearing
scanning speech (ataxic dysarthria) abnormal staccato-like speech due to a lesion of
the cerebellum orcerebellar pathways
scaphocephaly (dolichocephaly) premature closure of the sagittal suture
schizencephaly developmental birth defect characterized by abnormal slits or clefts in the cerebral
hemispheres extending from the cortical surface to the underlying ventricle
Schwann cell glial cell of the PNS that forms the insulating myelin sheath of peripheral axons
schwannoma WHO grade I benign peripheral nerve sheath tumor occurring commonly in
thecerebellopontine angle (cranial nerve VII) or in the bony foramina around the spinal cord (spinal
nerve root); characterized histologically by Antoni A and Antoni B tissue and Verocay bodies (zones
of nuclear palisading)
scintillating scotoma visual migraine aura consisting of shimmering lights followed by a dark spot
or partial loss of vision that may move across the visual field
scotoma island-like gap or blind spot in the visual field; pleural=scotomata
secondary progressive clinical course of multiple sclerosis that initially is relapsing-remitting and
then becomes progressive at a variable rate, possibly with an occasional relapse and minor
remission
secondary symptoms symptoms referable to secondary effects of a lesion e.g., edema, blockage
ofcerebrospinal fluid pathways, stretching of vessels
sectoranopia loss of vision in a wedge of the visual field
seizure discrete event due to sudden, transient, excessive neuronal discharges in the brain
sella turcica saddlelike prominence on the upper surface of the sphenoid bone of the skull, situated
in themiddle cranial fossa and containing the pituitary gland
senile plaque see neuritic plaque
sensory trick specific trigger a patient uses to relieve dystonia, e.g., touching the outer canthus of
the eye to temporarily relieve blepharospasm
septal nuclei neuronal structures in the rostral forebrain adjacent to the septum pellucidum that
communicate with the hippocampus, amygdala, hypothalamus,midbrain, habenula, cingulate gyrus,
and thalamus septum pellucidum membrane extending ventrally from the body of the corpus
callosum that separates the two lateral ventricles from each other setting sun sign forced depression
of the eyes due to pressure on the dorsalmidbrainin the setting of hydrocephalus; see
also Parinaud’s syndrome
shadow plaque foci of myelin preservation at the periphery of active multiple sclerosis plaques
thought to represent partial remyelination
sharp wave EEG pattern consisting of a transient electrical discharge with a pointed peak and a
duration of 70-200 milliseconds that stands out from ongoing background activity; has a strong
association with epilepsy
Shy-Drager syndrome older term for a variant of multisystems atrophy characterized by
preferential degeneration of the intermediolateral cell column of the spinal cord and substantia
nigra producing symmetricparkinsonism and autonomic failure
sialorrhea drooling; increased salivation
simple tic tic involving a limited number of muscles; simple vocal tics are meaningless noises such
as grunting or throat clearing; simple motor tics are focal movements such as eye blinking or facial
grimacing
single fiber electromyography electrodiagnostic test in which potentials of muscle fibers
innervated by a single axon are recorded; normal response is for fibers to be activated with
consistent latencies whereas inneuromuscular junction disorders, latencies among muscle fibers in a
single motor unit are variable (increasedjitter); most sensitive test for myasthenia gravis
Sjogren's syndrome an autoimmune disorder that prohibits production of tears and saliva
skew deviation hypertropia in which the eyes move vertically in opposite directions due to
acquiredsupranuclear or vestibulo-ocular disruption
sleep latency speed of falling asleep
sleep paralysis temporary (seconds to minutes) inability to move or talk that occurs during sleep-
to-wake or wake-to-sleep transitions; one of the symptoms of narcolepsy, but also experienced by
some non-narcoleptic individuals
slow wave sleep see non-REM sleep smooth pursuit smooth following eye movements that
maintain fixation
solitary nucleus and tract sensory nucleus of the medulla that receives afferent taste information
from nerves VII, IX, and X and mediates the gag, cough, carotid sinus, and other visceral reflexes
soma cell body, which contains the nucleus and endoplasmic reticulum somatosensory evoked
potentials (SSEP) series of waves that reflect sequential activation of neural structures along the
somatosensory pathways following electrical stimulation of peripheral nerves (typically elicited by
stimulation of the median nerve at the wrist, the common peroneal nerve at the knee, and/or the
posterior tibial nerve at the ankle and recorded from electrodes placed over the scalp, spine, and
peripheral nerves)
somesthesia sensation
somnambulism (sleep walking) arising from bed during a period when there is a simultaneous
occurrence of incomplete wakefulness and nonREM sleep; typically occurs in the first third of the
night during deep sleep
soporific causing or tending to induce sleep, such as a hypnotic drug
spasticity abnormal increase in muscle tone and reflexes, manifested as a velocity dependent
spring-like resistance to moving or being moved; indicates an upper motor neuron lesion
spike EEG pattern consisting of a transient electrical discharge with a pointed peak and a duration
of less than 70 milliseconds that stands out from ongoing background activity; has a strong
association with epilepsy spike-and-wave complex generalized synchronous pattern seen
on electroencephalogram, consisting of a sharply contoured fast wave followed by a slow wave; seen
in generalized epilepsy
spina bifida failure of bone fusion in the posterior midline of the vertebral column resulting in a
bony cleft through which the meninges and varying quantities of spinal cord tissue protrude
spina bifida occulta closed spinal dysraphism characterized by posterior vertebral defect and
various overlying cutaneous anomalies (e.g., lipoma, patch of hair); often associated with other
spinal cord abnormalities spinal dysraphism failure of bone fusion in the posterior vertebral
column; classified as open (not covered by skin) or closed (covered by skin); see
also meningocele and myelomeningocele spinocerebellar ataxia group of hereditary
neurodegenerative disorders caused by expansion of a CAG triplet repeat and characterized by
progressive ataxia and variable other features such as neuropathy and hearing or visual loss
spinal accessory nerve (cranial nerve XI) motor nerve originating partly from
the medulla (nucleus ambiguus—innervating laryngeal muscles) and partly from the spinal cord
(accessory nucleus in the ventral horn of the cervical cord—innervating the sternocleidomastoid and
trapezius muslces); lesion results in weakness in turning the head to the opposite side and elevating
the shoulder
spinocerebellar tract fiber tract originating in the spinal cord and carrying proprioceptive input to
theipsilateral cerebellum
spinothalamic tract axonal tract carrying information on pain and temperature that arises from
the posterior nerve roots, which ascend a few segments in Lissauer’s tract before synapsing in the
substantia gelatinosa, crossing to the opposite side of the cord in the anterior commisure, and
traveling in the anterolateral aspect of the cord up to the thalamus and cortex
splenium thickened posterior border of the corpus callosum
spondylosis degenerative disease of the vertebral column that can result in spinal cord
compression
spongiform encephalopathy progressive neurodegenerative disorder associated with
various prion agents that produce spongy changes in the brain (e.g., Creutzfeldt-Jakob disease, kuru)
spreading cortical depression brief wave of intense cortical activation followed by a marked
decrease inneuronal activity and reduced blood flow that starts in the occipital cortex and spreads
anteriorally at a rate of 2-6 mm/min; thought to underline migraine aura
status epilepticus medical emergency defined as more than 30 minutes of either
continuous seizure activity or two or more sequential seizures without full recovery of consciousness
in between
status migrainosus migraine attack that persists for > 72 hours and often leads to hospitalization
stereognosis ability to recognize objects by touch
stereotypy repetitive stereotyped movements commonly seen in tardive dyskinesia, Tourette
syndrome, or autism
stocking-glove typical distribution on the body where symptoms/signs of
peripheral neuropathy are evident (toes to knee and fingers to wrist)
strabismus misalignment of the eyes that is either developmental (due to a miscalibration of the
binocular vergence system in the cerebral cortex at some point in infancy or childhood) or acquired
(due to a palsy of a cranial nerve or extraocular muscle)
stria medullaris white matter tract connecting the anterior hypothalamus and septal nuclei in the
medial basalforebrain with the habenula
stria terminalis white matter tract containing amygdaloid efferents to the septal nuclei in the
medial basalforebrain and nuclei of the anterior hypothalamus
striate cortex see calcarine cortex
striatonigral degeneration (SND) older term for a variant of multisystems atrophy characterized
by degeneration of the striatum and the substantia nigra producing symmetric parkinsonism that
does not respond to levodopa or dopamine agonists
striatum part of the basal ganglia consisting of the caudate and putamen separated by fibers of the
anterior limb of the internal capsule
stroke sudden loss of neurological function caused by a blockage or rupture of a blood vessel to the
brain or spinal cord; includes infarction and hemorrhage subtypes
stupor condition of unresponsiveness from which the patient can only be aroused by vigorous and
repeated stimuli; once stimulus ceases, patient lapses back into unresponsiveness
subacute developing over days to weeks; suggests an expanding lesion (e.g, tumor or abscess)
subarachnoid hemorrhage bleeding in the subarachnoid space most commonly due to trauma or
rupture of an aneurysm or arteriovenous malformation
subarachnoid space actual space separating the pia and arachnoid that surround the brain and
spinal cord; contains cerebrospinal fluid, arteries and veins, and filaments of arachnoid matter,
giving it the appearance of a spider web
subclinical seizure electrographic seizure without clinical manifestations subcortical portion of
the brain immediately below the cerebral cortex; includes corona radiata, internal capsule, basal
ganglia, and thalamus, among others
subcortical leukoencephalopathy see Binswanger’s disease
subdural hemorrhage collection of blood in the subdural space following trauma to small bridging
veins or in elderly patients with cerebral atrophy or those with clotting abnormalities
subdural space potential space between the dura and arachnoid that can be filled with
blood, cerebrospinal fluid, or pus
subhyaloid hemorrhage accumulation of blood near the optic disc seen on fundoscopic exam
insubarachnoid hemorrhage
subiculum division of the parahippocampal gyrus adjacent to the hippocampal fissure that is the
major source of efferent fibers from the hippocampal formation to rostral structures in the
basal forebrain
substantia gelatinosa narrow, dense, vertical band of gray matter forming the dorsal part of the
posterior column of the spinal cord and serving to integrate the sensory stimuli that give rise to the
sensations of pain and temperature
substantia nigra nucleus in the midbrain tegmentum that is divided into the pars compacta, a
region of compactly organized dopaminergic cells that innervate the striatum and cerebral cortex,
and the pars reticulata, a region containing loosely organized cells that is a pallidal division of
the basal ganglia and sends its output to the thalamus and superior colliculus
subthalamic nucleus (subthalamus) nucleus in the ventral diencephalon that modulates the
output of thebasal ganglia from the internal segment of the globus pallidus to the thalamus
sulcus groove in the cerebral cortex separating two gyri
superior cerebellar peduncle (brachium conjunctivum) principle efferent fiber bundle from
thecerebellum; fibers decussate in the midbrain and end primarily in the red
nucleus and dorsal thalamus; lesions of the caudal SCP before the decussation result
in ipsilateral deficits in motor coordination whereas lesionsrostral to the decussation result
in contralateral deficits; afferent fibers from the ventral spinocerebellar tracttravel in the SCP to
bring proprioceptive information from the lower body to the cerebellum
superior colliculus paired structures on the dorsal surface of the rostral midbrain that receive
unconscious visual input directly from the retina and help orient the head and eyes to all types of
sensory stimuli
superior sagittal sinus venous structure occupying the convex margin of the falx cerebri and
draining the upper part of the cerebral hemispheres
supranuclear central connections rostral to the cranial nerve nuclei
suprasellar above the sella turcica
supratentorial above the tentorium cerebelli, i.e., cerebral cortex, thalamus, and basal ganglia
suture junction between two bones of the skull: coronal separates the 2 frontal bones from the
parietal bones; metopic separates the frontal bones; sagittal separates the 2 parietal bones;
lambdoid separates the occipital bone from the 2 parietal bones
Sylvian fissure (lateral fissure or lateral sulcus) prominent long, deep fissure on the lateral
surface of thecerebral hemisphere that divides the posterior frontal and anterior parietal lobes from
the superior temporal lobe
sympathetic nervous system part of the autonomic nervous system concerned with preparing
the body for fear, fight, or flight; preganglionic fibers arise from the lateral horns of the spinal
segments T1-L2
symptomatic epilepsy epilepsy that is due to a known cause (e.g., tumor)
syncope temporary loss of consciousness due to a lack of blood flow to the brain
syndrome of inappropriate ADH secretion (SIADH) disorder of osmoregulation involving
excessive release of arginine vasopressin (antidiuretic hormone), which causes excessive water
retention by the kidney, leading to a dilutional hyponatremia; occurs in a wide range of neurological
disorders and other medical conditions
synesthesia
condition associated with involuntary perceptual experiences that are elicited by stimuli that would
not be expected to elicit such a response—a crossing of sensory modalities, e.g., experiencing colors
in response to numbers, letters, and words
synucleinopathies
group of neurodegenerative diseases characterized by neuronal or glial inclusions composed of
alpha-synuclein; includes idiopathic Parkinson disease and diffuse Lewy body disease
syringobulbia central cavitation (cystic lesion) within the spinal cord (syringomyelia) that extends
up to themedulla and pons
syringomyelia central cavitation (cystic lesion) of the spinal cord, usually in the cervical region,
producing a distinctive cape-like distribution of spinothalamic tract sensory loss while leaving
the dorsal columns relatively intact
tardive symptoms that develop slowly or appear long after inception, e.g., tardive dyskinesia
occurring after chronic exposure to dopamine antagonists
tau microtubule-associated protein that is functionally modulated by phosphorylation and is
hyperphosphorylated in several neurodegenerative diseases.
tauopathies group of neurodegenerative diseases characterized predominantly by abnormalities of
tau protein; includes frontotemporal dementia, progressive supranuclear palsy,
corticobasal degeneration
teardrop fracture triangular fracture of the anteroinferior aspect of a vertebral body due to axial
loading with flexion or extension; often unstable associated with ligamentous injury and/or spinal
cord injury
tectospinal tract descending pathway from midbrain tectum to spinal inter- and motor neurons
that control anti-gravity posture and locomotion and that probably mediate tonic neck reflexes
tectum dorsal surface of the midbrain that contains the superior and inferior colliculi
tegmentum floor of the midbrain that contains the substantia nigra and the red nucleus
teichopsia see fortification spectrum
telencephalon anterior portion of the prosencephalon, constituting the cerebral hemispheres
temporal lobe epilepsy partial epilepsy arising from the temporal lobe of the brain
tendon release (tenotomy) surgical procedure involving division of a severely contracted tendon
in the management of spasticity
tension-type headache nonspecific headache that is typically dull, aching, and bilateral, and is
often described as a tightening band-like sensation around the head or neck; may be related to
muscle tightening in the back of the neck and/or scalp
tentorium cerebelli fold of dura mater that covers the cerebellum and supports the occipital lobes
of thecerebrum
tetany repetitive, spontaneous axonal discharges at high rates of up to 300 Hz producing intense
muscle spasm in the setting of electrolyte or acid-base disturbance
tethered cord attachment of the spinal cord to the vertebral column or subcutaneous tissues by a
thickenedfilum terminale, fibrous band, diastematomyelia, dermal sinus tract, or lipoma resulting in
a low-lying conus medullaris (i.e., below the L2-3 interspace)
tetraplegia see quadriplegia
thalamus large ovoid mass of gray matter in the dorsal aspect of the diencephalon that is located
medial to theinternal capsule and caudate and functions as a relay station between the cerebral
cortex and the brainstem and spinal cord
thunderclap headache sudden onset of severe head pain with neck stiffness that may be
associated with altered consciousness or focal neurological deficits; suggests subarachnoid
hemorrhage
tic repetitive, stereotyped, simple or complex movements that can be voluntarily suppressed for
short periods of time (e.g., eye blinking or throat clearing)
tilmus see floccillation
time-intensity profile of the temporal features of a patient’s symptoms that provides clues about
etiology of the disease process; acute, subacute, recurrent-remittent, or chronic-progressive
tinnitus sound experienced subjectively with no external source, most commonly ringing, buzzing,
or roaring
titubation tremor of the head and neck
Todd's paralysis temporary (minutes to hours or rarely days) post-seizure mono-
or hemiplegia; indicatesseizure was focal onset; sometimes term used for other temporary focal
post-seizure deficits, such as aphasia or sensory abnormalities
tolerance gradual loss of response to a drug with prolonged use
Tolosa-Hunt syndrome rare painful ophthalmoplegia due to a granulomatous inflammation of
the cavernous sinus (paralysis of the third, fourth, and/or sixth cranial nerves) typically relieved by
corticosteroids
tomacula focal area of myelin thickening creating a sausage-like appearance of nerves; common in
the geneticneuropathy, Hereditary Liability to Pressure Palsies
tonic-clonic seizure (grand mal seizure) generalized seizure characterized by initial contraction
of the muscles (tonic phase), which may involve tongue biting and urinary incontinence, followed by
rhythmic muscle contractions (clonic phase)
tonic neck reflexes movements and postures of the arm and leg when the neck is bent forwards,
backwards, or to the side that are present in normal infants and are incorporated in many bodily
movements of normal children and adults
tonic seizure generalized seizure that involves stiffening of the entire body
tonsilar herniation herniation of the cerebellar tonsils through the foramen magnum
torsion see cyclotorsion
torticollis form of dystonia in which the neck muscles contract involuntarily, causing the head to
turn
Tourette syndrome childhood onset movement disorder characterized by simple or
complex tics and often associated with obsessions, compulsions, and attention deficit disorder
transcortical motor aphasia impairment of language production (non-fluent aphasia) sparing
repetition due to a lesion in the anterior extrasylvian region (prefrontal and medial frontal cortex)
transcortical sensory aphasia impairment of language comprehension (fluent aphasia) sparing
repetition due to a lesion in the posterior extrasylvian region (inferior temporo-occipital cortex)
transcutaneous electric nerve stimulation (TENS) method of pain control involving application
of electrical impulses to nerve endings via electrodes that are attached to a stimulator by flexible
wires and placed on the skin; thought to block the transmission of pain signals to the brain
transformed migraine migraine pattern that has changed from episodic to chronic, often related
to the overuse of analgesics (medication overuse headache)
transient ischemic attack abrupt focal loss of neurologic function caused by reduction in blood
flow that persists less than 24 hours and clears without residual disability
transtentorial (central) herniation
downward displacement of the cerebral hemispheres pushing
the diencephalon and midbrainthrough the tentorial notch; symptoms classically follow
a rostrocaudal deterioration
transverse myelitis inflammatory disease involving both sides of the spinal cord in which motor
and sensory deficits occur below the level of the lesion; occurs commonly in multiple sclerosis and
various infectious and connective tissue disorders
tremor involuntary, rhythmic oscillatory movements about a fixed point due to alternating or
synchronous contractions of agonist and antagonist muscles; see
also action, essential, intention, physiologic, postural,resting, and rubral tremor
trigeminal nerve (cranial nerve V) mixed sensory and motor nerve made up of ophthalmic,
maxillary, and mandibular divisions responsible for sensation from the face, oral and nasal cavities,
and supratentorial dura(but not posterior scalp) and motor innervation of the muscles of
mastication; sensory fibers originate in the gasserian ganglion and (1) descend to the upper cervical
cord in the spinal tract of V then ascend in the trigeminothalamic tract to the thalamus (pain,
temperature, touch), (2) enter the main sensory nucleus of V and ascend to the thalamus (tactile
and proprioceptive sensation), or (3) enter the mesencephalic nucleus (jawproprioception)
trochlear nerve (cranial nerve IV) motor nerve innervating the superior oblique muscle, which
depresses and intorts the eye; only cranial nerve to exit dorsally and cross the midline before
emerging from thebrainstem—thus a lesion of the nucleus (which is in the caudal midbrain) affects
the contralateral eye
trigonocephaly premature closure of the metopic suture producing bowing of the forehead
triple flexion spinal reflex consisting of flexion at the hip, knee, and ankle in response to
stimulation of the sole of the foot; indicates corticospinal tract lesion
truncal sensory level level on the trunk below which sensation is impaired; sign of spinal cord
lesion
two-point discrimination ability to detect two stimuli presented simultaneously at decreasing
distance as being two separate stimuli; for normal tactile two-point discrimination, the two points of
calipers or a paperclip should be recognized at a separation of 2-4 mm on the lips and finger pads,
8-15 mm on the palms, and 3-4 cm on the shins
U fibers short U-shaped white matter tracts that lie just beneath the cerebral cortex and connect
adjacent gyri
uncal herniation displacement of the uncus of the temporal lobe and the hippocampal
gyrus towards the midline and over the lateral edge of the tentorium due to an expanding lesion in
the lateral middle cranial fossaor temporal lobe; earliest consistent sign is an ipsilateral dilating pupil
due to compression of the ipsilateral third cranial nerve
uncus most anterior part of the parahippocampal gyrus
upper motor neuron 1st order neurons that remain in the CNS and synapse with lower motor
neurons; lesions result in spasticity, hyperreflexia/extensor plantar response (upgoing toe)
vacuolar myelopathy vacuolation of myelin in the posterior and lateral columns of the primarily
thoracic spinal cord occurring in AIDS and resulting in paraparesis, sensory ataxia, and incontinence;
resembles themyelopathy associated with vitamin B12 deficiency