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L Cestnick

Publications and source records attributed to L Cestnick.

4 recordsLinked to original sources
PubMed2001

Cross-modality temporal processing deficits in developmental phonological dyslexics.

Neuroanatomical evidence suggests that poor readers may have abnormal lateral (LGN) and medial (MGN) geniculate nuclei responsible for temporal processing in visual and auditory domains respectively (Livingstone & Galaburda, 1993). Although behavioral evidence does support this neuroanatomical evidence in that poor readers have performed poorly on visual and auditory tasks thought to require the utilization of the LGN and MGN, respectively, appropriate examination of the coexistence of these behavioral abnormalities in the same population of poor readers has yet to take place. The present study examined correlations between visual and auditory temporal processing scores of all readers (collapsed groups), good readers, and poor readers who were isolated into phonological and surface dyslexic subtypes. The same subjects and data from Cestnick and Coltheart (1999) and Cestnick and Jerger (2000) were used to run the analyses. Results demonstrated a multitude of correlations between these tasks for the phonological dyslexic group only. It is contended that cross-modality temporal processing deficits may exist in poor nonlexical (phonological dyslexics) as opposed to poor lexical (surface dyslexics) readers. It is conceivable that phonological dyslexics may also have deficiencies within the LGN and MGN, or perhaps within systems related to these nuclei. The precise cause of these processing patterns and correlations is still unknown.

Child↗
PubMed2000

Auditory temporal processing and lexical/nonlexical reading in developmental dyslexics.

Relationships between lexical/nonlexical reading and auditory temporal processing were examined. Poor nonlexical readers (poor nonword readers, phonologic dyslexics) had difficulty across tone tasks irrespective of speed of presentation or mode of recall. Poor lexical readers (poor irregular word readers, surface dyslexics) had difficulty recalling tones in a sequence only when they were presented rapidly. Covariate analysis supported these findings, revealing that nonlexical (nonword) reading performance is associated with general auditory performance, but lexical (irregular word) reading is particularly associated with auditory sequencing. These findings suggest that phonologic and surface dyslexics perform differently on nonspeech auditory tasks. Because the two different types of poor readers did not differ significantly on tests of memory and learning but did differ on auditory tasks, we suggest that their performance on the auditory tasks may reflect auditory processing abnormalities as opposed to more general learning or memory difficulties. In addition to these observed qualitative differences between groups on the tone tasks, collapsing groups (all readers) revealed significant correlations between nonword reading and the Same-Different tone tasks in particular, whereas irregular word reading was not associated with any tone tasks; there also appears to be a quantitative relationship between nonlexical reading and Same-Different tone task performance as better or worse nonword reading predicts better or worse performance on the Same-Different tone tasks. In particular, it is conceivable that an auditory temporal processing deficit might contribute to poor nonword reading.

Auditory Perceptual Disorders↗
PubMed1999

The relationship between language-processing and visual-processing deficits in developmental dyslexia.

Some research on developmental dyslexia focuses on linguistic abnormalities such as poor reading of nonwords or poor reading of exception words. Other research focuses on visual abnormalities such as poor performance on psychophysical tasks believed to assess the functioning of the magnocellular and parvocellular layers of the lateral geniculate nucleus (LGN). Little is known about what the relationships are between these two types of abnormalities. We measured nonword reading, exception word reading, and performance with Ternus apparent movement displays (the perception of which is believed to depend upon the magnocellular and parvocellular pathways) in dyslexic children and children without reading difficulties. Our results indicate that performance on the Ternus task is related to nonword reading ability but not to exception word reading ability. We offer two alternative interpretations of these findings. According to the first of these, nonword reading requires a serial left-to-right allocation of covert attention across the letter string being read and the neural systems involved in this attentional process also play a part in responses to the Ternus display. According to the second, poor nonword reading and abnormal Ternus performance are not directly related: perinatal/neurodevelopmental insult has affected the LGN (influencing Ternus performance) and the adjacent medial geniculate nucleus (MGN; affecting phonological ability) and the MGN abnormalities may be more functionally related to poor nonword reading.

Attention↗