- Also known as macrostereognosis. Both terms stem from the Greek adjective makros (large) and the medical term stereognosis (from the Greek words stereos (solid, tight, compact) and gnosis (insight)), meaning the ability to identify solid objects through tactile sensation. The term macrostereognosia was introduced in or shortly before 1945 by the Jewish neurologist Lipman Halpern to denote a tactile "illusion in which an object, held in the palm of one's hand, for example, appears to be significantly more bulky and massive than it actually is. The term macrostereognosia is used in opposition to "microstereognosia. Pathophysiologi-cally, both conditions are associated primarily with thalamic dysfunction and with mild parietal sensory impairment. Conceptually, macrostere-ognosia can be considered the tactile equivalent of "macropsia (i.e. seeing things as larger than they are). The two conditions have also been known to occur in conjunction.ReferencesCritchley, M. (1953). The parietal lobes. London: Edward Arnold & Co.Halpern, L. (1945). Macrostereognosia. An unusual phenomenon in a case of thalamic syndrome. Journal of Nervous and Mental Disease, 102, 260-264.Halpern, L. (1959). Simultaneous visual and tactile illusions of size. Confinia Neurologica, 19, 301-306.
Dictionary of Hallucinations. J.D. Blom. 2010.