Cognitive Neurophysiology Lab
Gerry Stefanatos, D. Phil.
Genetics of Turner Syndrome Neurocognitive Phenotype
This research focuses on Estrogen, genetic deficiencies, and cognitive function in Turner syndrome. Girls and women with
Turner Syndrome (TS) are born with just one X chromosome instead of the two X chromosomes found in genetically normal women.
Currently, approximately 60,000 girls are affected in the United States, with approximately 800 new cases diagnosed each year.
The genetic abnormalities in TS are associated with a lack of normal estrogen production, infertility and coronary or other
physical problems. Women and girls with TS usually have normal intelligence, but they may demonstrate specific cognitive
deficits, including difficulty in learning math and performing visual-spatial coordination tasks such as mentally rotating
objects in space.
Some researchers have demonstrated positive effects of estrogen replacement on cognition and behavior in women who lack adequate
level of the hormone for various reasons. The extent to which the phenotypic cognitive deficits in T.S. are related to the
X chromosome or a combination of hormonal and genetic factors is not entirely clear. We are collaborating with Judith Ross,
MD and Andrew Zinn, MD in their efforts to define the genetic and hormonal determinants of the TS. phenotype.
Word Deafness And Temporal Processing
Pure word deafness (PWD) is a rare neurological syndrome characterized by severe difficulties in understanding and reproducing
spoken language, with sparing of written language comprehension and speech production. The pathognomonic disturbance of auditory
comprehension appears to be associated with a breakdown in processes involved in mapping auditory input to lexical representations
of words, but the functional locus of this disturbance and the localization of the responsible lesion has been disputed.
The deficiencies in decoding language occur at a stage of analysis that markedly impairs the processing of speech sounds,
words, phrases and sentences, but leaves environmental sound recognition and identification relatively preserved. Because
deficits are specific to the auditory modality, this pattern of impairment has also been referred to as “word sound deafness”.
Extensive research on a remarkable case diagnosed with word deafness pointed to a disturbance of left hemisphere auditory
mechanisms that preferentially analyze rapid spectrotemporal variations in frequency. The findings have important implications
for our conceptualization of pure word deafness and its subtypes. Further work is studying the nature of these deficits and
in developing a better understanding of cortical hearing.
Selected Publications:
Ross, J.L., Stefanatos, G.A., Kushner H., Bondy C., et al. The effect of genetic differences and ovarian failure: intact
cognitive function in adult women with premature ovarian failure versus Turner Syndrome, Journal of Clinical Endochrinology
Metabolism, (2004), 89: 1817-22
Stefanatos, G.A. (1993), frequency modulation analysis in children with Landau-Kleffner syndrome. Annals of the New York
Academy of Sciences, 682, 412-4.
Stefanatos, G.A, Gershkoff, A. and Madigan, S. (2005). Word Deafness.
