Iran Specialty Board Neurology key terms

Reperfusion therapy using a fibrinolytic drug to dissolve an acute intracerebral thrombus; indicated in selected patients within a narrow time window after onset, after hemorrhage is excluded by imaging.

Endovascular removal of an intracranial arterial clot using a stent retriever or aspiration catheter; used for large-vessel occlusion, with benefit extending to selected patients with salvageable tissue on perfusion imaging.

A 10-point topographic scoring system applied to non-contrast CT that grades the extent of early ischemic change in the middle cerebral artery territory; lower scores indicate larger established infarction and poorer reperfusion prognosis.

A standardized 15-item clinical scale scoring consciousness, gaze, visual fields, facial and limb motor function, ataxia, sensation, language, dysarthria, and extinction; total scores quantify stroke severity and guide treatment decisions.

Deposition of beta-amyloid in leptomeningeal and cortical arterioles causing vessel fragility; a leading cause of lobar intracerebral hemorrhage and of recurrent microbleeds in older adults, often without hypertension.

Small rounded foci of signal loss on susceptibility-sensitive MRI sequences representing hemosiderin from prior tiny hemorrhages; their distribution (lobar versus deep) helps distinguish amyloid angiopathy from hypertensive small-vessel disease.

A rim of hemosiderin coating the surface of the brain or spinal cord, seen as dark signal on susceptibility-weighted MRI, reflecting chronic subarachnoid bleeding; may cause ataxia, hearing loss, or myelopathy.

The intrinsic ability of cerebral arterioles to dilate and constrict so that blood flow remains relatively constant across a range of perfusion pressures; it is impaired in acute ischemia and after severe head injury.

A continuous seizure or repeated seizures without recovery between them, lasting long enough to risk neuronal injury; operational time thresholds differ for convulsive and nonconvulsive forms, and treatment is time-critical.

Prolonged electrographic seizure activity without prominent motor manifestations, presenting as altered awareness, confusion, or subtle twitching; diagnosis requires EEG because the clinical picture mimics metabolic encephalopathy.

An EEG waveform, such as a spike, sharp wave, or spike-and-wave complex, that stands out from background activity and reflects abnormal synchronized neuronal firing; it supports but does not by itself diagnose epilepsy.

An EEG pattern of high-amplitude activity alternating with periods of near-flat suppression, indicating severely depressed cortical function; seen in deep anesthesia, hypothermia, or profound encephalopathy and used as a titration target.

The electrical waveform recorded from a needle electrode when the muscle fibers of one motor unit discharge together; its amplitude, duration, and recruitment pattern help separate neuropathic from myopathic disease.

Spontaneous brief discharges of a single denervated muscle fiber recorded at rest on needle EMG; they appear weeks after nerve injury and indicate active denervation rather than normal muscle activity.

The summed electrical response of a muscle to supramaximal stimulation of its motor nerve, recorded in nerve conduction studies; its amplitude reflects the number of excitable axons and muscle fibers.

The summed response of a sensory nerve recorded after electrical stimulation; its amplitude falls with axonal loss and ganglionopathy, while it is typically preserved in preganglionic root lesions.

A fall in the amplitude or area of a compound muscle action potential when the nerve is stimulated proximal rather than distal to a lesion, indicating failure of action potentials to propagate past that point.

The synapse between a motor nerve terminal and the motor end plate of a muscle fiber, where acetylcholine is released and binds receptors to trigger contraction; disorders here cause fatigable weakness.

A nerve conduction technique delivering trains of stimuli to detect a decrement in the compound muscle action potential, which indicates impaired neuromuscular transmission as in myasthenia gravis.

Discrete IgG bands in cerebrospinal fluid that are absent from matched serum, reflecting intrathecal antibody synthesis; a supportive finding in multiple sclerosis but not specific to it.

The ratio of cerebrospinal fluid to serum IgG, corrected for albumin, used to estimate intrathecal immunoglobulin production; an elevated value supports an inflammatory central nervous system process but is not disease-specific.

An autoantibody against the astrocytic water channel that defines neuromyelitis optica spectrum disorder; it is highly specific and predicts longitudinally extensive myelitis and optic neuritis.

The incidental finding of MRI lesions typical of multiple sclerosis in a person with no symptoms suggesting demyelination; a proportion of such individuals later develop clinical disease.

Involuntary choreiform or dystonic movements that appear in people with Parkinson disease, often at peak levodopa effect after years of treatment; management involves adjusting dose timing and drug formulations.

Implantation of electrodes in deep gray matter targets such as the subthalamic nucleus or globus pallidus, delivering adjustable electrical current to reduce tremor, rigidity, and motor fluctuations in movement disorders.

Acting out of dreams during rapid eye movement sleep because of lost muscle atonia, often preceding synucleinopathy such as Parkinson disease by years; it is a strong prodromal marker.

A reversible focal neurologic disturbance, most often visual, that develops gradually and precedes or accompanies headache; it reflects cortical spreading depression rather than ischemia.

The convergence of trigeminal and upper cervical afferents in the brainstem and upper cervical cord; its activation underlies the fronto-occipital distribution of many headaches and neck-associated pain.

Daily or near-daily headache worsened by frequent use of acute analgesic or triptan drugs; it improves after the offending medication is withdrawn and preventive treatment is established.

New or enlarging contrast enhancement and edema on post-treatment imaging that reflects inflammation or necrosis rather than tumor growth; it can mimic progression and requires cautious interpretation.

Imaging that measures blood flow and volume in tissue, such as dynamic susceptibility contrast or arterial spin labeling; used to distinguish tumor recurrence from radiation injury and to grade vascularity.

Spread of malignant cells into the pia and arachnoid and the cerebrospinal fluid, causing headache, cranial nerve palsies, and radicular symptoms; diagnosis rests on CSF cytology and MRI.

The constriction of both pupils when light enters one eye, mediated by afferent fibers in the optic nerve and efferent fibers in the oculomotor nerve; comparing direct and consensual responses localizes lesions.

A weaker pupillary constriction when light is swung from the healthy eye to the affected eye, indicating asymmetric afferent conduction loss in the optic nerve or extensive retina.

Impaired adduction of one eye with nystagmus of the abducting eye on lateral gaze, caused by a lesion of the medial longitudinal fasciculus; it is classically associated with demyelinating disease in young adults.

Continuous measurement of pressure inside the skull using an external ventricular drain or parenchymal probe, used to guide treatment of raised pressure after severe brain injury and to calculate cerebral perfusion pressure.