A meta-analytic review of verbal fluency deficits in Huntington's disease

A meta-analysis of 30 studies with 1,511 participants was conducted to estimate and compare the magnitude of deficits on tests of phonemic and semantic fluency for patients with Huntington's disease (HD) relative to healthy control participants. As has been found for patients with focal frontal cortical lesions (but not for patients with focal temporal cortical lesions), symptomatic HD patients were comparably impaired on tests of phonemic and semantic fluency (rs = .71 and .73, respectively). However, in contrast to patients with focal frontal lobe injuries, fluency deficits did not qualify as differential deficits relative to verbal intelligence or psychomotor speed. Therefore, for patients with HD, deficits on tests of phonemic and semantic fluency do not appear to reflect executive dysfunction but a more generalized cognitive impairment.