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From the Division of Cognitive Neurology (Drs. Hillis, Boatman, Hart, and Gordon), Johns Hopkins Medical Institutions; Department of Cognitive Science (Drs. Hillis, Boatman, Hart, and Gordon), Johns Hopkins University; the Zanvyl Kreiger Mind/Brain Institute (Drs. Boatman, Hart, and Gordon); and the Division of Audiology (Dr. Boatman), Department of Otolaryngology, Johns Hopkins Medical Institutions, Baltimore, MD.
Address correspondence and reprint requests to Dr. Argye Hillis, Department of Neurology, Pathology 509, Johns Hopkins Hospital, 600 North Wolfe Street, Baltimore, MD 21287; e-mail: argye{at}JHMI.edu
OBJECTIVE: To identify the cognitive and neuroanatomic bases of neologistic jargon aphasia with spared comprehension and production of written words.
METHODS: Detailed analysis of performance across experiments of naming, reading, writing, repetition, and word/picture matching by a 68-year-old woman (J.B.N.) served to identify which cognitive mechanisms underlying naming and word comprehension were impaired. J.B.N.s impairments were then simulated by selectively "lesioning" a computer model of word production that has semantic, word form, and subword phonologic levels of representation (described by Dell in 1986).
RESULTS: In comprehension experiments, J.B.N. made far more errors with spoken word input than with written word or picture input (chi-square = 4059; df = 1; p < 0.0001) despite intact auditory discrimination. In naming experiments (with picture, definition, or tactile input), J.B.N. made far more errors in spoken output relative to written output (chi-square = 1456; df = 1; p < 0.0001). These selective impairments of spoken word processing were simulated by reducing connection strength between word-level and subword-level phonologic units but maintaining full connection strength between word-level and semantic units in Dells model. The simulation yielded a distribution of error types that was nearly identical to that of J.B.N., and her CT and MRI scans showed a small subarachnoid hemorrhage in the left sylvian fissure without infarct. Cerebral angiogram showed focal vasospasm in sylvian branches of the left middle cerebral artery.
CONCLUSION: Focal left perisylvian dysfunction can result in a highly selective "disconnection" between word-level and subword-level phonologic representations manifest as neologistic jargon aphasia with intact understanding and production of written words.
Key words: AphasiaAnomiaPure word deafnessVasospasm.
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