Huntington's Disease Research Today is a free monthly online journal that collates and summarizes the latest research about Huntington's Disease, including details on genetics, causes, symptoms, treatment.

Semantic and phonemic sequence effects in random word generation: a dissociation between Alzheimer's and Huntington's disease patients.

Taylor KI, Salmon DP, Monsch AU, Brugger P

Neuropsychology Unit, Department of Neurology, University Hospital Zürich, Zürich, Switzerland. taylork@uhbs.ch

Alzheimer's disease (AD) patients perform worse on category than letter fluency tasks, while Huntington's disease (HD) patients show the reverse pattern or comparable impairment on both tasks. We developed a random word generation task to further investigate these deficits. Twenty AD and 16 HD patients and 20 elderly and 16 middle-aged controls guessed which of three pictures (hat, cat, or dog) landed on a die's top face sixty times. Three consecutive response pairings were possible: semantic (cat-dog), phonemic (hat-cat), and neutral (hat-dog). Since healthy individuals avoid repeating meaningful associates ("repetition avoidance"), an increased pairing frequency reflects processing deficits. AD patients produced more semantic and HD patients more phonemic pairings compared to their respective control groups, indicating selective semantic and phonemic processing deficits in AD and HD patients, respectively.

Published 16 May 2005 in J Int Neuropsychol Soc, 11(3): 303-10.
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