title: The effect of interference on temporal order memory in premanifest and manifest Huntington's disease.
abstract: BACKGROUND
  Frontal-striatal dysfunction has been linked to cognitive impairment in Huntington's disease (HD). The frontal lobes play a role in memory for the temporal order in which items occur in a sequence. However, little is known about temporal order memory in HD or how it may be affected by interference.
  
  
  OBJECTIVE
  The study assessed temporal order memory in patients with manifest HD (n = 20), premanifest gene carriers for HD (Pre-HD; n = 18), and controls (n = 25) using a computerized radial 8-arm maze.
  
  
  METHODS
  On the sample phase of each trial, participants viewed a random sequence of circles appearing one at a time at the end of each arm. On the choice phase, participants viewed two sample phase circles and chose the circle occurring earliest in the sequence. Manipulations of the temporal lag (defined as the number of circles occurring in the sample phase sequence between the two choice phase circles) were conducted to systematically vary interference. Temporally proximal lags were hypothesized to generate more interference relative to temporally distal lags.
  
  
  RESULTS
  The Pre-HD group was significantly impaired (p < 0.05) compared to controls on proximal temporal lags (high interference) but matched controls on distal lags (low interference). HD patients improved as a function of increased lag but demonstrated significant impairments (p < 0.05) across lags relative to controls.
  
  
  CONCLUSIONS
  Temporal order memory is differentially affected by interference during the premanifest and manifest stages of HD. The study identifies a fundamental, yet relatively unexamined, deficit associated with HD.
authors: Department of Psychology, San Diego State University, San Diego, CA, USA.
authors: Diane R
authors: DR
authors: Nicoll
authors: Veterans Affairs, San Diego Health Care System, San Diego, CA, USA Department of Psychiatry, University of California San Diego, San Diego, CA, USA.
authors: Eva
authors: E
authors: Pirogovsky
authors: Department of Psychology, San Diego State University, San Diego, CA, USA.
authors: Adrienne E
authors: AE
authors: Collazo
authors: Department of Psychology, San Diego State University, San Diego, CA, USA.
authors: Savanna M
authors: SM
authors: Tierney
authors: Department of Neurosciences, University of California - San Diego, La Jolla, CA, USA.
authors: Jody
authors: J
authors: Corey-Bloom
authors: Department of Psychology, San Diego State University, San Diego, CA, USA San Diego State University/University of California - San Diego Joint Doctoral Program in Clinical Psychology, San Diego, CA, USA.
authors: Paul E
authors: PE
authors: Gilbert
mesh_terms: D001288:Attention / Q000502:physiology*; D001921:Brain / Q000503:physiopathology*; D005260:Female; D006801:Humans; D006816:Huntington Disease / Q000503:physiopathology* / Q000523:psychology; D008297:Male; D008568:Memory / Q000502:physiology*; D008875:Middle Aged; D009483:Neuropsychological Tests
keywords: Sequence; basal ganglia; frontal lobes; interference; visuospatial