Glossary of Common Neurologic Terms ABCs Term referring to airway, breathing, and with agraphia) or without writing deficits circulation management of a patient with (alexia without agraphia). impaired consciousness or breathing. Steps Allodynia Nonpainful cutaneous stimuli caus- include ensuring airway access, delivering ing pain. oxygen either nasally or via intubation if Amnesia Partial or complete loss of the ability needed, and establishing intravenous access to learn new information or to retrieve previ- plus others. ously acquired knowledge. Absence seizure or petit mal seizure Typically Amaurosis fugax Transient monocular blind- begins with arrest of speech and the abrupt ness. This usually comes from an internal onset of loss of awareness without loss of carotid artery embolus temporarily occluding muscle tone or falling followed by seconds of the ophthalmic artery. staring without being able to communicate. Amyotrophic lateral sclerosis Progressive The individual then becomes alert but does neurodegenerative fatal disorder affecting not recall the episode. primarily upper and lower motor neurons in Accommodation Sensory nerves having the spinal cord and motor cortex. dynamic firing rates that decline with time Amyotrophy Wasting of muscles usually from even though the stimulus is maintained. denervation. Acute disseminated encephalomyelitis Anal reflex Reflexive contraction of anal (ADEM) Complex monophasic illness, sphincter upon perianal sensory stimulation. particularly in children, that often follows a Aneurysm Abnormal dilatation or bulging of recent infection or occasionally vaccination an intracranial artery wall, usually at bifurca- characterized by an abrupt encephalopathy tions of the circle of Willis. often with obtundation, hemiparesis, ataxia, Anisocoria Unequal pupil size. cranial nerve palsies, visual impairment, and Ankle jerk Deep tendon reflex (Achilles reflex) seizures. elicited by striking the Achilles tendon at the Afferent pathway Axons leading to the brain ankle resulting in foot plantar flexion. or spinal cord. Anterior horn Gray matter in the ventral spinal Agnosia Implies lack of knowledge and is cord that contains neurons including anterior synonymous with an impairment of recogni- horn cells (lower motor neurons). tion. An example is visual agnosia in which Anterior root Motor nerves from anterior horn patient cannot arrive at the meaning of previ- neurons from ventral spinal cord exit to point ously known nonverbal visual stimuli despite of joining mixed peripheral nerve at the dor- normal visual perception and alertness. sal root ganglion. Agraphia Inability to recognize numbers/letters Anton’s syndrome Lesions involving the written on the palm or fingertips. occipital and parietal lobes that produce Alexia Acquired reading impairment that may blindness or a homonymous hemianopia that be accompanied with writing deficits (alexia is denied by the patient. L. E. Davis, S. Pirio Richardson, Fundamentals of Neurologic Disease, 2nd Edition 277 DOI 10.1007/978-1-4939-2359-5, © Springer Science+Business Media, LLC 2015 278 Glossary of Common Neurologic Terms Aphasia Disorder of expression or comprehen- Bellʼs palsy Abrupt idiopathic peripheral sion of spoken language due to dysfunction seventh cranial nerve facial palsy of ipsilat- of language centers in dominant cerebral eral facial muscle weakness plus variable cortex or thalamus. The most common forms unilateral loss of tearing, taste appreciation, are Broca’s aphasia, Wernicke’s aphasia, and and ability to dampen loud noises. Recovery global aphasia. is usually good. Apoptosis Genetically programmed neuronal Benign paroxysmal positional vertigo Brief cell death that may be normal or abnormal. vertigo when rotating ones head upward or Apraxia Inability to perform a learned act downward without accompanying nausea or despite demonstrated ability to perform hearing loss that develops from abnormal components of the act usually due to dys- endolymphatic fluid movement in a posterior function of a parietal lobe. The most common semicircular canal usually due to the presence forms are limb , constructional, and dressing of otoconia that broke loose from the macula apraxia. of the utricle. Arteriovenous malformation (AVM) Abnor- Biceps reflex Deep tendon reflex elicited by mal blood vessel complex consisting of arter- hitting the biceps tendon resulting in brief ies, veins, and capillaries located in the brain contraction of the biceps muscle. or spinal cord that often hemorrhage. Blood-brain barrier Separation of circulating Arteritis Inflammation of walls of arteries. blood from brain extracellular fluid due to Astereognosis The inability to distinguish and tight junctions around all brain capillaries recognize small objects based on size, shape, that do not exist in normal circulation. and texture when placed in the hand that has Botulinum toxin Potent neurotoxin produced normal primary tactile sensory input. by Clostridium botulinum causing botu- Ataxia Incoordination of limb or body move- lism with prolonged muscle paralysis. The ments, particularly gait, often due to impair- enzymatic toxin inactivates proteins in the ment of cerebellar function. posterior synaptic side of the neuromuscu- Athetosis Involuntary movements characterized lar junction preventing normal release of by slow, sinuous, twisting changes of arms, acetylcholine. legs or body. Brachioradialis reflex Deep tendon reflex Atrophy Wasting of muscle/s from disuse or elicited by hitting the distal radius resulting denervation. in brief contraction of the triceps muscle. Aura Migraine prodrome that usually is visual Bradykinesia or akinesia Difficulty in mov- with blurred visual and colored flashing ing despite intact motor nerves and normal lights seen with eyes open or closed that lasts muscles as seen in Parkinson’s disease. 5–15 min. Brain abscess Localized intracerebral infection Autism Childhood illness affecting language that begins as a focal area of cerebritis, devel- and interpersonal relationships. oping into a collection of pus surrounded by Babinski sign Extensor response of the great a capsule, that is usually due to a bacteria but toe with fanning of the other toes in response occasionally from a fungus or protozoa. to stimulus on sole of foot. The extensor Broca’s aphasia Motor speech disorder plantar response is normal in infants to about (expressive aphasia, nonfluent or anterior 9 months, thereafter reflects damage to the aphasia) due to dysfunction located in the corticospinal tract (upper motor neuron sign). dominant frontal lobe and characterized by Basal ganglia Deep gray matter nuclei of effortful, sparse, agrammatic, halting, trun- the cerebral hemispheres comprising puta- cated speech with loss of normal language men, caudate, globus pallidus, subthalamic melody. nucleus, substantial nigra, and ? thalamus. Glossary of Common Neurologic Terms 279 Bruit Sound due to turbulence of blood passing ing a physician to turn off a ventilator and a narrow artery segment, often heard from individuals to donate organs. the internal carotid artery in the neck. Cerebral edema An excess accumulation Bulbar Refers to the medulla and pons of the of fluid in the intracellular or extracellular lower brainstem. spaces of the brain. Vasogenic edema is due Calcarine cortex Primary visual cortex located to breakdown of the tight endothelial junc- in the medial occipital lobe. tions which make up the blood–brain barrier Caloric test Placement of warm or cool water (BBB) allowing intravascular proteins and in the external canal to evaluate eye move- fluid to penetrate into the brain extracel- ments from stimulation of the vestibulo- lular space. Cytotoxic edema has an intact ocular reflex. BBB and is due to disruption of cellular Carpal tunnel syndrome Compression mono- metabolism leading to glial cell swelling neuropathy of the median nerve at the carpal from impairment of the sodium and potas- canal of the wrist characterized by pain, sium pump. Interstitial edema in obstructive tingling, and numbness involving mainly the hydrocephalus is due to disruption of the palmar aspect of the thumb, index finger, CSF-brain barrier resulting in trans-epen- and middle finger plus variable weakness dymal flow of CSF into the brain into the of median nerve innervated thenar hand extracellular spaces and the white matter. muscles. Cerebral Palsy Refers to a group of disorders Charcot-Marie-Tooth disease or Hereditary that affect motor, cognitive, communica- Motor and Sensory Neuropathy 1 Domi- tion, and behavioral systems. It is the most nant autosomal genetic disease affecting common cause of disability in childhood and distal myelinated axons of limbs, espe- is due to a permanent, non-progressive brain cially legs producing distally symmetrical injury. polyneuropathy. Channelopathies Group of diseases with Cauda equina Lumbosacral nerve roots in the abnormal ion channels (pores) in cell mem- lumbar and sacral vertebral canal before the branes resulting from genetic disorders most exit via neural foramina. often affecting muscle or brain. Caudal Lower in the neural axis as in brain- Cheyne-Stokes respirations Regular cyclic stem is caudal to the basal ganglia. oscillations of breathing between hyperpnea Central pontine myelinolysis Demyelinating or over breathing and apnea. condition affecting the pons or outside of the Chorea Abnormal involuntary movements pons (known as extrapontine myelinolysis) characterized by rapid flicks or jerks of limb, occurring at times of severe osmotic