ZweiPunktTest

ZweiPunktTest, or the two-point test, is a psychophysical procedure used to assess cutaneous spatial acuity by determining the smallest distance at which a person can perceive two simultaneous tactile stimuli as distinct.

Stimuli are applied with an esthesiometer or calipers fitted with blunted tips. The examiner presents pairs of points at varying separations on the skin, commonly the fingertip, lips, or tongue. The subject reports whether they feel one point or two; a forced-choice or method-of-constant-stimuli approach may be used to estimate the threshold.

The measured threshold reflects the integrity of somatosensory pathways. Higher thresholds indicate reduced tactile resolution due to peripheral nerve damage, neuropathy, or central lesions. Normative values exist for different sites and ages, enabling comparisons across individuals and over time.

There are static and dynamic variants; the static version uses stationary stimuli, while the dynamic variant involves moving points or strokes across the skin. Reliability depends on site, skin condition, age, and examiner technique; proper standardization improves consistency and reduces variability.

Limitations include subjectivity of responses, learning effects, and variations in skin properties. The test is used in clinical neurology and rehabilitation to assess sensory loss or recovery, as well as in research on somatosensory mapping and tactile discrimination after injury.

See also: two-point discrimination; esthesiometer; tactile sensibility; neurological examination.