In about one third of patient with the chief complaint of vertigo and dizziness the instability of stance and gait is the leading symptom. This is in particular true for patients suffering from sensory deficits (vestibular, somatosensory, visual), from neurodegeneration (cerebellar ataxia, Parkinsonian syndromes), and from functional disorders (somatoform and phobic dizziness). To make a correct diagnosis, it is essential assessing all deficits in a structured manner. This includes tests of postural control and gait under different conditions, i.e. eyes open and closed, tandem stance, walking at different velocities, stance and gait during cognitive dual tasks. A qualitative assessment can easily be done by skilled clinical observation, complemented by established tests and scores (e.g. timed-up-and-go test). Instrumented stance and gait tests support (1) the differential diagnosis by providing parameters invisible for the clinical eye (e.g. 14 Hz sway in orthostatic tremor), (2) the estimation of the fall risk by quantification of relevant parameters (e.g. stride to stride gait variability), and (3) the assessment of the disease course with and without intervention (e.g. gait velocity and gait variability after spinal tap in normal pressure hydrocephalus). Methods for apparative testing currently develop rapidly and in a dynamic manner. Currently, the most relevant methods used in patients suffering from vertigo and dizziness are stabilometry/posturography with force plates for the quantification of body sway, sensor carpets for the assessment of spatial and temporal stride parameters, and wearable sensors for the assessment of mobility and fall frequency in daily life, outside the laboratory. Instrumented tests, however, are of no value without state of the art clinical workup based on the patient's history and clinical bedside examination. Used with clear focus, laboratory tests for stance and gait deliver valuable information on the individual impairment, thus supporting diagnostics and therapeutic decisions.
