COURSEĪ diagnosis of TIA is usually made after the symptoms have passed. Another possibility is vasospasm leading to temporary narrowing of the blood vessel lumen. The most likely cause of a TIA is the blockage of the cerebral blood vessel by an embolus or thrombus that then subsequently dissolves, allowing blood flow to resume before permanent damage occurs (see Stroke Mechanisms). It should be noted that isolated symptoms of dizziness, dysequilibrium, tinnitus, transient amnesia, and drop attacks are generally not due to TIA. In contrast, vertebrobasilar TIAs present with bilateral or side alternating weakness, motor and sensory disturbances, as well as varying degrees of homonymous visual impairment, gait ataxia, diplopia, dysphagia, dysarthria and dizziness. "Amaurosis fugax" refers to transient monocular blindness due to a carotid TIA involving the territory of the ophthalmic artery.
Carotid TIAs can present as unilateral weakness, motor or sensory disturbances of the face or upper or lower limb, dysphasia, or homonymous hemianopsia.
The symptoms of a TIA depend on the artery being occluded. In fact, the more typical duration for a TIA is about 10 minutes longer deficits probably produce at least some permanent brain damage. A TIA is defined as a neurological deficit lasting less than 24 hours, caused by brain ischemia.
The most common cause of short-term neurological episodes is a transient ischemic attack, or TIA.
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