What term describes the loss of equilibrium or sensation of instability and dizziness?

The term that describes the loss of equilibrium or sensation of instability and dizziness is "vertigo." Vertigo is characterized by the perception that either the surroundings or oneself is moving or spinning, which often leads to a feeling of dizziness and imbalance. This sensation can stem from various causes, including inner ear disorders, neurological conditions, or issues with the vestibular system, which plays a critical role in balance.

Ataxia refers to a lack of voluntary coordination of muscle movements, which can also affect balance but is not specifically linked to the sensation of spinning or dizziness that defines vertigo. Disequilibrium can describe a general loss of balance but does not convey the specific sensory experience of spinning associated with vertigo. Paresthesia is a term used for sensations of tingling or numbness, unrelated to balance or dizziness. Thus, vertigo accurately captures the experience of dizziness and loss of equilibrium that the question describes.