Key Terms

accommodation

in vision, a change in the ability of the eye to focus on objects at different distances

accommodation–convergence reflex

coordination of somatic control of the medial rectus muscles of either eye with the parasympathetic control of the ciliary bodies to maintain focus while the eyes converge on visual stimuli near to the face

anterograde amnesia

inability to form new memories from a particular time forward

aphasia

loss of language function

ataxia

movement disorder related to damage of the cerebellum characterized by loss of coordination in voluntary movements

Babinski sign

dorsiflexion of the foot with extension and splaying of the toes in response to the plantar reflex, normally suppressed by corticospinal input

cerebrocerebellum

lateral regions of the cerebellum; named for the significant input from the cerebral cortex

check reflex

response to a release in resistance so that the contractions stop, or check, movement

clasp-knife response

sign of UMN disease when a patient initially resists passive movement of a muscle but will quickly release to a lower state of resistance

conduction aphasia

loss of language function related to connecting the understanding of speech with the production of speech, without either specific function being lost

conductive hearing

hearing dependent on the conduction of vibrations of the tympanic membrane through the ossicles of the middle ear

conjugate gaze

coordinated movement of the two eyes simultaneously in the same direction

convergence

in vision, the movement of the eyes so that they are both pointed at the same point in space, which increases for stimuli that are closer to the subject

coordination exam

major section of the neurological exam that assesses complex, coordinated motor functions of the cerebellum and associated motor pathways

cortico-ponto-cerebellar pathway

projection from the cerebral cortex to the cerebellum by way of the gray matter of the pons

cranial nerve exam

major section of the neurological exam that assesses sensory and motor functions of the cranial nerves and their associated central and peripheral structures

cytoarchitecture

study of a tissue based on the structure and organization of its cellular components; related to the broader term, histology

deep tendon reflex

another term for stretch reflex, based on the elicitation through deep stimulation of the tendon at the insertion

diplopia

double vision resulting from a failure in conjugate gaze

edema

fluid accumulation in tissue; often associated with circulatory deficits

embolus

obstruction in a blood vessel such as a blood clot, fatty mass, air bubble, or other foreign matter that interrupts the flow of blood to an organ or some part of the body

episodic memory

memory of specific events in an autobiographical sense

expressive aphasia

loss of the ability to produce language; usually associated with damage to Broca’s area in the frontal lobe

extrinsic muscles of the tongue

muscles that are connected to other structures, such as the hyoid bone or the mandible, and control the position of the tongue

fasciculation

small muscle twitch as a result of spontaneous activity from an LMN

fauces

opening from the oral cavity into the pharynx

fibrillation

in motor responses, a spontaneous muscle action potential that occurs in the absence of neuromuscular input, resulting from LMN lesions

flaccid paralysis

loss of voluntary muscle control and muscle tone, as the result of LMN disease

flaccidity

presentation of a loss of muscle tone, observed as floppy limbs or a lack of resistance to passive movement

flocculonodular lobe

lobe of the cerebellum that receives input from the vestibular system to help with balance and posture

gait

rhythmic pattern of alternating movements of the lower limbs during locomotion

gait exam

major section of the neurological exam that assesses the cerebellum and descending pathways in the spinal cord through the coordinated motor functions of walking; a portion of the coordination exam

gnosis

in a neurological exam, intuitive experiential knowledge tested by interacting with common objects or symbols

graphesthesia

perception of symbols, such as letters or numbers, traced in the palm of the hand

hemisection

cut through half of a structure, such as the spinal cord

hemorrhagic stroke

disruption of blood flow to the brain caused by bleeding within the cranial vault

hyperflexia

overly flexed joints

hypotonicity

low muscle tone, a sign of LMN disease

hypovolemia

decrease in blood volume

inferior cerebellar peduncle (ICP)

input to the cerebellum, largely from the inferior olive, that represents sensory feedback from the periphery

inferior olive

large nucleus in the medulla that receives input from sensory systems and projects into the cerebellar cortex

internuclear ophthalmoplegia

deficit of conjugate lateral gaze because the lateral rectus muscle of one eye does not contract resulting from damage to the abducens nerve or the MLF

intorsion

medial rotation of the eye around its axis

intrinsic muscles of the tongue

muscles that originate out of, and insert into, other tissues within the tongue and control the shape of the tongue

ischemic stroke

disruption of blood flow to the brain because blood cannot flow through blood vessels as a result of a blockage or narrowing of the vessel

jaw-jerk reflex

stretch reflex of the masseter muscle

localization of function

principle that circumscribed anatomical locations are responsible for specific functions in an organ system

medial longitudinal fasciculus (MLF)

fiber pathway that connects structures involved in the control of eye and head position, from the superior colliculus to the vestibular nuclei and cerebellum

mental status exam

major section of the neurological exam that assesses cognitive functions of the cerebrum

middle cerebellar peduncle (MCP)

large, white-matter bridge from the pons that constitutes the major input to the cerebellar cortex

motor exam

major section of the neurological exam that assesses motor functions of the spinal cord and spinal nerves

neurological exam

clinical assessment tool that can be used to quickly evaluate neurological function and determine if specific parts of the nervous system have been affected by damage or disease

paramedian pontine reticular formation (PPRF)

region of the brain stem adjacent to the motor nuclei for gaze control that coordinates rapid, conjugate eye movements

paresis

partial loss of, or impaired, voluntary muscle control

plantar reflex

superficial reflex initiated by gentle stimulation of the sole of the foot

praxis

in a neurological exam, the act of doing something using ready knowledge or skills in response to verbal instruction

procedural memory

memory of how to perform a specific task

pronator drift

sign of contralateral corticospinal lesion when the one arm will drift into a pronated position when held straight out with the palms facing upward

receptive aphasia

loss of the ability to understand received language, such as what is spoken to the subject or given in written form

red nucleus

nucleus in the midbrain that receives output from the cerebellum and projects onto the spinal cord in the rubrospinal tract

retrograde amnesia

loss of memories before a particular event

Rinne test

use of a tuning fork to test conductive hearing loss versus sensorineural hearing loss

Romberg test

test of equilibrium that requires the patient to maintain a straight, upright posture without visual feedback of position

rubrospinal tract

descending tract from the red nucleus of the midbrain that results in modification of ongoing motor programs

saccade

small, rapid movement of the eyes used to locate and direct the fovea onto visual stimuli

sensorineural hearing

hearing dependent on the transduction and propagation of auditory information through the neural components of the peripheral auditory structures

sensory exam

major section of the neurological exam that assesses sensory functions of the spinal cord and spinal nerves

short-term memory

capacity to retain information actively in the brain for a brief period of time

Snellen chart

standardized arrangement of letters in decreasing size presented to a subject at a distance of 20 feet to test visual acuity

spasticity

increased contraction of a muscle in response to resistance, often resulting in hyperflexia

spinocerebellar tract

ascending fibers that carry proprioceptive input to the cerebellum used in maintaining balance and coordinated movement

spinocerebellum

midline region of the cerebellum known as the vermis that receives proprioceptive input from the spinal cord

stereognosis

perception of common objects placed in the hand solely on the basis of manipulation of that object in the hand

stroke

(also, cerebrovascular accident (CVA)) loss of neurological function caused by an interruption of blood flow to a region of the central nervous system

superficial reflex

reflexive contraction initiated by gentle stimulation of the skin

superior cerebellar peduncle (SCP)

white-matter tract representing output of the cerebellum to the red nucleus of the midbrain

transient ischemic attack (TIA)

temporary disruption of blood flow to the brain in which symptoms occur rapidly but last only a short time

vermis

prominent ridge along the midline of the cerebellum that is referred to as the spinocerebellum

vestibulo-ocular reflex (VOR)

reflex based on connections between the vestibular system and the cranial nerves of eye movements that ensures that images are stabilized on the retina as the head and body move

vestibulocerebellum

flocculonodular lobe of the cerebellum named for the vestibular input from the eighth cranial nerve

Weber test

use of a tuning fork to test the laterality of hearing loss by placing it at several locations on the midline of the skull

Wernicke’s area

region at the posterior end of the lateral sulcus in which speech comprehension is localized