Development of above normal language and intelligence 21 years after left hemispherectomy

Abstract

Neuropsychologic follow-up studies of a 5 1/2-year-old boy who had left hemispherectomy for seizures showed that he had developed superior language and intellectual abilities. These findings contrast with recent reports indicating that the plasticity of the nervous system may have been overrated and contradict reports of restricted development of language functions after left and of nonlanguage functions after right hemispherectomy for perinatal lateralized brain lesions. Following removal of the left hemisphere, including "the classical language zones," the right hemisphere and other intact residual structures may provide the necessary substrata for the development of above normal adult language and intellectual capacities.

Does the Intracarotid Amobarbital Procedure Predict Global Amnesia After Temporal Lobectomy?

“…Such a phenomenon has support from other clinical observations, including improved cognitive functioning after hemispherectomy in infantile hemiplegia (44,45). Cavazutti and colleagues noted improvement in cognitive function of the contralateral temporal lobe after ipsilateral removal of small temporal lobe tumors (with no associated mass effect) (46).…”

Spoken Language Outcomes after Hemispherectomy: Factoring in Etiology

“…Even though hemispherectomy for the treatment of intractable epilepsy began in the 1950s and 1960s (Griffith & Davidson, 1966;Krynouw, 1950;McFie, 1961;Wilson, 1970), detailed studies of the effect of hemispherectomy on language appeared only in the 1970s (Dennis, 1976;Dennis & Kohn, 1975;Dennis & Whitaker, 1976;Gott, 1973;Smith & Sugar, 1975). Although, as of 1998, 333 cases of pediatric hemispherectomies have been reported worldwide (Holthausen, 1998), studies of the effects of hemispherectomy on language have been limited to either case studies or small samples.…”

The Antithesis of Entropy: Biosemiotic Communication from Genetics to Human Language with Special Emphasis on the Immune Systems

“…With that in mind, and with the findings from "split-brain" research and cases of complete agenesis of the corpus callosum in hand-particularly, the results showing that both hemispheres can perform all of the pragmatic mapping functions in many cases of complete agenesis and in cases where the hemispherectomy or commissurotomy occurs very early in a child's life [54][55][56]59]-It becomes reasonable, even necessary, to infer that the pragmatic mapping formula must describe the essential neuroarchitecture not only of the whole brain, but also of its parts. Figure 4 shows that the predicted organization is found in the dominant hemisphere, and by inference from cases of complete agenesis of the corpus callosum along with early hemispherectomies and commissurotomies, we know that the subordinate hemisphere is similarly organized.…”

“…With that diagram in mind, it is clear from research with early hemispherectomies (ones performed while the brain is still developing), that the pragmatic mapping formula must also generalize to the subordinate hemisphere. Otherwise, how would it be possible to explain cases of agenesis of the corpus callosum [59] and/or early hemispherectomies or commissurotomies where it seems possible for the persons affected to perform all of the normal pragmatic mapping functions with either hemisphere all by itself [51,54]? The predicted architecture, again, is empirically demonstrated in both hemispheres.…”

“…It is exceedingly unlikely, based on the analyses summarized in Figures 1-6 that the complete agenesis of a corpus callosum could leave all intellectual and motor functions unaffected-i.e., perfectly within the normal expected limits. Although Sperry [51] and others [59] reported on cases of agenesis of the corpus callosum which were characterized as leaving intellectual abilities unaffected-seemingly controverting the global negative impact of such agenesis predicted by the sign theory discussed here-more recent work suggests that the measures and observations of intellectual performance in the various instances of the studies just cited were probably too impoverished to detect deficits in the sorts of abstract thinking required for the comprehension and/or production of metaphor, irony, and so forth. Controverting those earlier studies of complete agenesis of the corpus callosum, and in conformity with the predictions of the more developed semiotic model of the human neuroarchitecture as spelled out in the foregoing discussion, several more recent studies deserve mention.…”