Abstract
Astereognosis is the tactile inability to recognize objects placed in the palms by touch with the eyes closed or blind-folded in the presence of intact primary sensory modalities. Stereognosis is usually considered a function of the contralateral sensory cerebral cortex. However, lesions of several anatomic areas and pathologic entities have been reported to be associated with astereognosis. Only two previous reports linked traumatic injury to isolated astereognosis: following surgical evacuation of traumatic parietal extradural hematoma and following bullet injury in the neck in 1992 and 1919, respectively.
All the pertinent literature was analyzed, focusing on the relevant definitions, clinical spectra, pathoanatomical processes, assessment, management, and outcomes of astereognosis. Also, an illustrative case was presented. The case highlights isolated post-traumatic left hand astereognosis in a 17-year-old boy following a blunt trauma to the head which resulted in a non-hemorrhagic contusion of the right post-central gyrus.
Post-traumatic isolated astereognosis is a rare and probably underreported sequel of traumatic brain injury. Neurosurgeons need to be more sensitive to the assessment and detection of subtle stereognostic deficits in general and in trauma patients in particular. Other anatomical areas, in addition to the contralateral post-central gyrus, may be considered in the pathogenesis of astereognosis with the involvement of the dorsal column medial lemniscus tract such as the brainstem, foramen magnum, and the cervical spinal cord. To the best of our knowledge, this rare case report is considered the second report on astereognosis following head trauma, and the third report on astereognosis following trauma in general.