Object agnosia; Tactile agnosia
Short Description or Definition
Astereognosis is defined as the inability to identify objects through touch without visual input.
Astereognosis has been subdivided into primary and secondary recognition deficits. Primary recognition deficits, also called morphognosia, reflect impairments in recognizing the physical features of the object (e.g., weight or texture). Secondary recognition deficits reflect a specific impairment in object recognition with spared primary recognition (for review, see De Renzi 1982).
Astereognosis can be common after stroke with one report indicating that up to 90% of patients demonstrate astereognosis (Connell et al. 2008). Damage to the cortical regions important for haptic input integration can cause astereognosis. This disorder, therefore, is common and can occur in the presence of many neurological disorders including brain (e.g., Knecht et al. 1996) or spinal cord tumors (Lesoin et al. 1986...
References and Readings
- Benton, A. L. (1969). Stereognosis test; Manual of instructions. Victoria: Neuropsychology Laboratory, Department of Psychology, University of Victoria.Google Scholar
- De Renzi, E. (1982). Disorders of space exploration and cognition. New York: Wiley.Google Scholar
- Reitan, R. M., & Wolfson, D. (1993). The Halstead-Reitan neuropsychological test battery: Theory and clinical interpretation. Tucson: Neuropsychology Press.Google Scholar