A failure to recognize a stimulus due to impaired perceptual abilities, although elementary sensory functions (acuity, color vision, etc.) are intact. Though most cases of apperceptive agnosia are visual, auditory and tactile cases have also been reported. Patients with visual apperceptive agnosia are a heterogeneous group who typically have damage in visual association cortices and appear to have a profound visual deficit. While both apperceptive and associative agnosics have difficulty with object naming, they can be differentiated in that the associative agnosic will be able to copy a drawing of the object, while the apperceptive agnosic will have difficulty drawing it or matching it to a visually similar stimulus.
References and Readings
- Bauer, R. M. (2012). Agnosia. In K. M. Heilman & E. Valenstein (Eds.), Clinical neuropsychology (5th ed., pp. 238–295). New York: Oxford University Press.Google Scholar