Biomedical subjects
Publications and source records attributed to Z H Hart.
Electrophysiologic dichotomy of abnormal EEGs, as reported by us previously, and normal evoked potentials, as reported in this communication, in patients with Rett syndrome, suggests a predominant gray matter pathophysiologic insult in this serious condition of unknown etiology.
Rett syndrome is a progressive neurologic condition, affecting only girls and characterized by acquired microcephaly, dementia, seizures, autistic behavior, spontaneous hyperventilation, spasticity, hyperreflexia and a peculiar characteristic stereotypic movement disorder. A review of 35 EEGs (obtained over 0-8.5 years of follow-up) in 9 such patients revealed a striking age-related change in the electroencephalographic pattern. Often initially normal, the EEG shows a variety of epileptiform abnormalities but intact background activity between 3 and 5 years. Between 5 and 10 years of age, the background activity exhibits some slowing, epileptiform abnormalities persist and paroxysmal high-amplitude theta activity occurs over extended periods, related to spontaneous hyperventilation. After 10 years, there is a general reduction in the epileptiform activity but further slowing of the background rhythms is usually observed. As all other laboratory tests are mostly normal in Rett syndrome, EEG promises to be a powerful tool in confirming the diagnosis in a compatible setting, in follow-up of these patients, and in objective evaluation of any future therapeutic interventional modalities in this serious and common condition.
Recent electrophysiologic studies have focussed attention on the X-linked adrenoleukodystrophy (ALD) and its myeloneuropathic variant. No organized studies are, however, yet available on its relatively recently described neonatal variant. We conducted electroencephalographic, electroretinographic and evoked response studies in 2 patients with neonatal ALD. In one patient, an infant, initial EEG, hypsarrhythmic in waking and somewhat periodic in sleep, showed dramatic improvement on ACTH therapy accompanied with a seizure-free status. The EEG and clinical improvement, however, were temporary. No improvement occurred following pyridoxine therapy. Her electroretinogram (ERG), visual evoked responses (VERs) and far-field short latency brain-stem auditory evoked responses were also abnormal. The latter studies probably reflected photoreceptor degeneration, optic nerve involvement, cochlear and/or auditory nerve involvement respectively in neonatal ALD. The other patient, a 3.5-year-old girl, also had an EEG characterized by a moderate- to high-amplitude slow background activity and high-amplitude multifocal, generalized or periodic paroxysmal discharges, but presence of some better formed theta frequencies in background activity precluded a hypsarrhythmic label on her EEG. Her ERGs and VERs were totally extinct but in contrast to the first patient, she had clear-cut optic atrophy and retinitis pigmentosa on ophthalmological examination.
A 14-year-old boy developed alopecia totalis shortly after a pertussis-like illness and, subsequently, developed chronic lymphocytic thyroiditis and diffuse polyneuritis.
A 23-month-old boy with progressive muscle weakness and severe cardiomyopathy was found to have oil red O positive vacuoles predominantly in type 1 muscle fibers. Serum carnitine was normal, but muscle carnitine content was decreased. Both parents were clinically normal, but the muscle carnitine level was low in the father. Despite oral treatment with carnitine, the condition progressed and was fatal. At autopsy, cardiac muscle showed borderline low carnitine content and numerous mitochondria, but no lipid accumulation.
We describe a 16-year-old boy who has a progressive dementia and seizures. On investigation, he was found to have a mitochondrial myopathy and elevated lactate levels in the blood and cerebrospinal fluid. His sister died at 18 years of age of a similar condition.
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