The traditional Japanese arrangement of cosleeping represents an environment in which parents are readily accessible to children during waking episodes. Physical proximity to the parents in infancy, but not at other ages, is associated with SRNC. The higher incidence of bruxism, chronic eczema, and day care use among children with frequent SRNC supports the hypothesis that nighttime anxiety may promote SRNC.

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Objective: To determine if apneic preterm infants currently treated with methylxanthines develop evidence of sleep deprivation from cumulative arousal and motor activational effects.Study Design: Sleep, wake, arousal and actigraphic movements were monitored in extubated clinically stable premature infants (N ¼ 37). Neonates were free of other medications for >72 h and were grouped based on methylxanthine exposure: >5 days with caffeine (n ¼ 14), >5 days theophylline (n ¼ 13) or no prior exposure (n ¼ 10).Result: Duration of methylxanthine treatment predicted increased arousals, wakefulness and actigraphic movements, and decreased active sleep. Recording from 1200 to 0500 hours, methylxanthine-treated groups showed reductions in all arousal parameters: waking state, number of wake epochs, brief arousals and composite arousal index, and shorter fast-burst, sleep-related motility than untreated controls. Conclusion:In apneic preterms, chronic methylxanthine treatment appears to produce sleep deprivation secondary to the stimulatory action of methylxanthines on arousal and motor systems.

Alexander disease is a leukodystrophy that is neuropathologically characterized by the presence of numerous Rosenthal fibers in astrocytes. Recently, mutations in the gene encoding glial fibrillary acidic protein (GFAP) were identified in patients with Alexander disease. We sequenced the GFAP gene of a Japanese girl who presented with typical symptoms of Alexander disease but in whom the diagnosis was not proven by histopathology. We identified a missense mutation, R239C, which is identical to the mutation previously reported to be most frequent. As was the case in previously described patients, our patient was also heterozygous for the de novo mutation. Interestingly, despite the fact that this is a de novo mutation, R239C was found to be common in different ethnic groups, implying that the site is a "hot spot" for mutagenesis. Molecular genetic analysis now makes the antemortem diagnosis of Alexander disease possible.

References1. Leigh RJ, Robinson DA, Zee DS. A hypothetical explanation for periodic alternating nystagmus: instability in the optokinetic-vestibular system. Ann NY Acad Sci 1981;374:619 -635. 2. Baloh RW, Honrubia V, Konrad HR. Periodic alternating nystagmus. Brain 1976;99:11-26. 3. Davis DG, Smith JL. Periodic alternating nystagmus: a report of eight cases. Am J Ophthalmol 1971;72:757-762. 4. Keane JR. Periodic alternating nystagmus with downward beating nystagmus: a clinicoanatomical case study of multiple sclerosis. Arch Neurol 1974;30:399 -402. 5. Dow ER, Anastasio TJ. Induction of periodic alternating nystagmus in intact goldfish by sinusoidal rotation. Neuroreport 1997;8:2755-2759. 6. Wearne S, Raphan T, Cohen B. Control of spatial orientation of the angular vestibuloocular reflex by the nodulus and uvula.Dentatorubral pallidoluysian atrophy (DRPLA) is an autosomal dominant disease that has a wide variety of clinical symptoms. 1 There is a correlation between age at onset and clinical symptoms. Progressive myoclonus epilepsy (PME) is a usual feature of juvenile DRPLA; but late adult DRPLA patients usually experience cerebellar ataxia and hyperkinetic involuntary movements such as choreoathetosis, often without myoclonus or epilepsy. 2 We report two unrelated patients with infantile DRPLA. Patient 1. The patient is a 4-year-old boy and the second child of healthy, nonconsanguineous Japanese parents without a family history of neurologic diseases. His father is 39 years old and his mother is 35 years old. He has a healthy 8-year-old brother. There were no major problems in the neonatal periods. He developed normally until age 6 months when his mother noticed decreased activity. At age 1 year, he could stand with support; but he began to regress slowly and became irritable. At age 2 years, he had difficulty controlling his head and swallowing, sometimes showing dystonic posture. Choreoathetosis of the limbs appeared and became prominent. At age 2 years 7 months, he had tonic convulsions. Various antiepileptic drugs did not control the convulsions.He was no longer able to fix or follow, but had light perception and normal optic fundus. Nystagmus was not noted. Muscle tone was variable, and deep tendon reflexes were exaggerated. Plantar response was absent. Oral dyskinesia, severe choreoathetosis, and dystonia were continuously seen. Myoclonus was not present.Laboratory examination including lysosomal enzyme activities, organic and amino acid analysis, and the level of lactate and pyruvate, were unremarkable. Histologic examination of the biopsied skin and muscle revealed no abnormalities.MRI of the brain showed atrophy of the cerebrum and cerebellum, brain stem, and delayed myelination ( figure, A and B).Patient 2. The patient is a 2-year-old girl and the second child of healthy, nonconsanguineous Japanese parents. Her father is 46 years old and her mother is 37 years old. Her 10-year-old brother has epilepsy and mild mental retardation. Her birth and development up to age 4 months were normal, but she could no...

The neuroradiological findings in four patients with Tay-Sachs disease are described in three phases of the clinical course. The basal ganglia and cerebral white matter show low density on computed tomography and high signal intensity on T2-weighted magnetic resonance imaging in the initial phase. The caudate nuclei are characteristically enlarged and protrude into the lateral ventricles in the first and second phases. The cerebral white matter shows low density on the CT which varies in extent from the second to third phases, and the whole brain becomes atrophic in the last phase. Thus, central nervous system involvement in the disease may begin in basal ganglia as well as in cerebral white matter.