Abstracts

Rationale: Blindness in candidates for epilepsy surgery occurs infrequently and there are no published precedents for conducting an intra-carotid amytal (ICA) test in such patients. This report describes the development and successful use of language and memory testing methods for a patient with ocular blindness. Methods: The subject is an adult patient with congenital ocular blindness who is a candidate for surgical treatment of the subject’s epilepsy. Language and memory test items employing tactile object recognition were developed and validated for the subject prior to injection. Different but equivalent test items were developed and used for the test validation phase and for the bilateral ICA tests.Results: The blind subject was able to successfully participate in the modified testing procedure during the pre-injection, practice phase of the test. Similarly, the subject was able to participate in actual clinical testing with the ICA test with valid results for the language and memory components of the test. The actual ICA test indicated that language lateralized to the hemisphere contralateral to the anticipated surgery. The memory portion of the ICA test predicted that the anticipated surgery should not result in serious harm to memory functioning. The patient subsequently had surgery consisting of a temporal lobectomy. Post-surgically, there was no subjective or objective cognitive morbidity.Conclusions: Epilepsy surgery programs will occasionally include patients with a variety of sensory or motor impairments that may present challenges during the pre-surgery evaluation phase. This presentation demonstrates one example of how significant sensory limitations can be overcome through careful modifications of the ICA testing process while still yielding information that is valid for clinical decision making purposes. The presentation also discusses the cerebral re-organization of language that has been reported to occur in patients with congenital blindness as a possible issue complicating the analysis of ICA test results in the area of language functioning.