Unique EEG pattern (comb-like rhythm) in neonatal maple syrup urine disease

A unique electroencephalographic pattern (the comb-like rhythm) is described in an infant with neonatal (classic) maple syrup urine disease. This pattern consists of bursts and runs of 5-7 Hz primarily monophasic negative (mu-like) activity in the central and central-parasagittal regions during wakefulness and sleep with the most abundant bursts occurring during quiet (non-REM) sleep. This pattern appeared during the first 2 weeks of life and was absent in the recording obtained 40 days after the initiation of dietary therapy. In the proper clinical setting this electroencephalographic pattern is diagnostic of maple syrup urine disease and can be distinguished from similar patterns occurring in normal infants and those with other encephalopathies.