Plasma Cobalamin Levels Affect Information Processing Speed in a Longitudinal Study of HIV-1 Disease

Gail Shor Posner, Robert Morgan, Frances Wilkie, Carl Eisdorfer, Marianna K. Baum

Research output: Contribution to journalArticlepeer-review

17 Scopus citations


Objective: To determine whether information processing speed is influenced by change in plasma cobalamin status in human immunodeficiency virus type 1 disease. Design: A longitudinal study, using autoregression, to evaluate the relationship between plasma cobalamin status and change in information processing speed assessed by Posner Letter Matching, Sternberg Short-Term Memory Search, Figure Visual Scanning and Discrimination of Pictures, and continuous paired associates learning tasks. Setting: University of Miami (Fla) School of Medicine from fall 1987 through summer 1991. Participants: Eighty-four human immunodeficiency virus type 1-infected homosexual men aged 20 to 55 years. None of the subjects displayed acquired immunodeficiency syndrome-defining symptoms at baseline; over the course of the study, 9.5% progressed to acquired immunodeficiency syndrome. Main Outcome Measures: Biochemical measurement of plasma cobalamin; performance on information processing speed tasks. Results: Significant improvement in the Posner Letter Matching NI-PI (Name Identity minus Physical Identity) differential was associated with becoming cobalamin adequate or remaining adequate. Becoming cobalamin deficient, in contrast, was associated with a significant decline in the speed of accessing overlearned name codes. Conclusion: Normalization of plasma cobalamin inadequacy in human immunodeficiency virus type 1 disease may provide significant improvement in the speed of retrieving overlearned information from long-term memory.

Original languageEnglish (US)
Pages (from-to)195-198
Number of pages4
JournalArchives of neurology
Issue number2
StatePublished - Feb 1995

ASJC Scopus subject areas

  • Arts and Humanities (miscellaneous)
  • Clinical Neurology


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