Landau–Kleffner syndrome

a rare childhood neurological disorder of unknown cause that is characterized by the sudden or gradual development of aphasia (inability to understand or express language) and an abnormal electroencephalogram (see electroencephalography). The syndrome usually occurs in children between the ages of 5 and 7 years who develop normally but then lose their language skills for no apparent reason. Many children with the disorder experience seizures, which generally disappear by adulthood. [first described in 1957 by William M. Landau and Frank R. Kleffner]

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Psychology term of the day

February 16th 2025

sun compass

the use of the sun as a directional stimulus in orientation and navigation. Because the sun appears to move across the sky during the day and has different trajectories in different seasons, a sun compass must be coupled with some form of time estimation. To head south at 9 a.m., one needs to keep the sun on the left, but at 3 p.m., one needs to keep the sun on the right. Studies of several species, ranging from bees to fish and birds, have demonstrated a time-compensated sun compass. For nocturnal species, there is evidence of a star compass.