Neurology -- Correspondence for Chang et al., 64 (5) 799-803

Correspondence published:

Reading impairment in the neuronal migration disorder of periventricular nodular heterotopia: Deborah K. Sokol, Meredith R. Golomb, Karen S. Carvahlo, Mary Edwards-Brown (14 June 2005)

Reply from authors: Bernard S. Chang (14 June 2005)

Reading impairment in the neuronal migration disorder of periventricular nodular heterotopia 14 June 2005

Deborah K. Sokol,
Indiana University School of Medicine
RI 1757 702 Barnhill Drive Indianapolis, IN 46202,
Meredith R. Golomb, Karen S. Carvahlo, Mary Edwards-Brown
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Re: Reading impairment in the neuronal migration disorder of periventricular nodular heterotopia

dksokol{at}iupui.edu Deborah K. Sokol, et al.

We read with interest the report by Chang et al on the association of bilateral periventricular nodular heterotopia with seizures and impaired reading in people with normal intelligence.
We performed extensive neuropsychological testing on a 16-year-old boy with a left perventricular heterotopion and left temporal lobe dysplasia diagnosed by magnetic resonance imaging and did not find any evidence of reading disability. Our patient came to evaluation because of academic difficulties. At the time of testing he had focal epilepsy which was well-controlled on lamotrigine. On the Wechsler Intelligence Scale for Children-III Edition, he had a Full Scale intelligence quotient (IQ) of 104, a Verbal IQ of 114, and a Performance IQ of 93. His Processing Speed Index was 64 (1 %tile). On the Gray Oral Reading Test-4, his Reading Quotient was 103 (58th %tile for age) with adequate reading rate, accuracy, frequency, and comprehension for age. On the Luria Nebraska Neuropsychologic Battery- Form 1, none of the 11 clinical scales or 5 ancillary scales were above the critical level of sixty-one. On the Wide Range Achievement Test-Edition III, his reading standard score was 94 at the high school level (34 %tile).
Our patient had normal reading ability. His slow processing speed contributed to his academic difficulty. This case supports the trend described by Chang et al that patients with fewer heterotopia show less cognitive impairment. We hypothesize that children with unilateral periventricular heterotopia may be less likely to develop reading impairment than children with bilateral heterotopia because there is less cortical involvement.

Reply from authors 14 June 2005

Bernard S. Chang,
Beth Israel Deaconess Medical Center and Harvard Medical School
NRB-268B, 77 Ave Louis Pasteur, Boston MA 02115
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Re: Reply from authors

bchang{at}bidmc.harvard.edu Bernard S. Chang

We appreciate the interest of Sokol et al in our findings. Their results support our demonstration of a relationship between the anatomical distribution of heterotopia and the cognitive consequences. Our study did not include any subjects with only a single heterotopic nodule or with other coexistent malformations, as in her case. We believe there are many potential mechanisms by which the presence of gray matter heterotopia could lead to a specific cognitive deficit, and further work is required to clarify them.