Refers to an impairment in spatial perception and stability.
The term can be used to mean vertigo, presyncope, disequilibrium, or a non-specific feeling such as giddiness or foolishness.
Cost of assessing dizziness in emergency rooms exceeds $4 billion per year.
The term is imprecise and may signify vertigo, lightheadedness, disorientation, confusion, generalized weakness, pre-syncope, or postural instability.
The inner ear contributes to the control of eye position, and the vestibular system keeps images stable on the retina.
Failure of peripheral vestibular function causes instability of images during the head motion, called oscillopia.
The most widely available vestibular test is videonystagmography, which includes oculomotor testing and the biaural, bithermal caloric test.
Significant caloric paresis is an indicator of vestibular hypofunction.
Spontaneous, unidirectional, predominately horizontal nystamus suggests acute peripheral vestibulopathy.
Posterior fossa brain lesions typically cause gaze-holding nystagmus or pure vertical nystagmus.
Complaints of dizziness have in common a disturbance in the sense of position or motion.
Invariably, dizziness impacts postural stability and gait, although the extent to which git is involved varies.
Can be induced by engaging in disorientating activities such as spinning.
Vertigo is a term used to describe the sensation of spinning or having one’s surroundings spin about them.
Vertigo represents about 25% of cases of occurrences of dizziness.
Disequilibrium refers to the sensation of being balance, and is most often characterized by frequent falls in a specific direction.
Disequilibrium is not often associated with nausea or vomiting.
Syncope refers to fainting.
Presyncope is lightheadedness and muscular weakness.
Non-specific dizziness is often related to a psychiatric illness diagnosed by excluding organic disease.
A stroke is the cause of isolated dizziness in 0.7% of people who present to the emergency room.
CNS lesions cause disturbances of gait and balance that frequently include excessively variable step length.
Peripheral nerve lesions in the limbs, such as an entrapment neuropathy, may cause abnormal abnormalities that repeat, machine like from one gate cycle to the next.
Four main types of dizziness: vertigo, disequilibrium, presyncope, and lightheadedness, accounting for about 50%, 15%, 15%, and 10%, respectively.
Dizziness causes:: 40% peripheral vestibular dysfunction, 10% central nervous system lesion, 15% psychiatric disorder, 25% presyncope/dysequilibrium, and 10% nonspecific dizziness.
The head eye test probes the vestibulo-ocular reflex which is abnormal in multiple vestibular disorders.
The head impulse test is performed as the patient fixates on the examiners nose with the patient’s head turned around 10° to the right or left of midline.
The examiner suddenly turns the patient’s head to one side or the other through about 20°.
Head impulse toward a damage peripheral vestibular system causes passive movement of the eyes with their head followed by a corrective saccade away from the week ear and back toward the intended direction of fixation.
In the dynamic visual acuity test of the vestibular-ocular reflex, the examiner oscillates the head in a plane at about 2 Hz: If near vision worsens from baseline by more than two lines of vision the test is abnormal.