title: Moderate relationships between NAA and cognitive ability in healthy adults: implications for cognitive spectroscopy.
abstract: BACKGROUND
  Proton Magnetic Resonance Spectroscopy ((1)H-MRS) is a non-invasive imaging technique that enables quantification of neurochemistry in vivo and thereby facilitates investigation of the biochemical underpinnings of human cognitive variability. Studies in the field of cognitive spectroscopy have commonly focused on relationships between measures of N-acetyl aspartate (NAA), a surrogate marker of neuronal health and function, and broad measures of cognitive performance, such as IQ.
  
  
  RESULTS
  In this study, we used (1)H-MRS to interrogate single-voxels in occipitoparietal and frontal cortex, in parallel with assessments of psychometric intelligence, in a sample of 40 healthy adult participants. We found correlations between NAA and IQ that were within the range reported in previous studies. However, the magnitude of these effects was significantly modulated by the stringency of data screening and the extent to which outlying values contributed to statistical analyses.
  
  
  CONCLUSIONS
  (1)H-MRS offers a sensitive tool for assessing neurochemistry non-invasively, yet the relationships between brain metabolites and broad aspects of human behavior such as IQ are subtle. We highlight the need to develop an increasingly rigorous analytical and interpretive framework for collecting and reporting data obtained from cognitive spectroscopy studies of this kind.
authors.affiliation: Aston Brain Centre, School of Life and Health Sciences, Aston University Birmingham, UK.
authors.forename: Tulpesh
authors.initials: T
authors.lastname: Patel
authors.affiliation: Birmingham Children's Hospital Birmingham, UK.
authors.forename: Jacqueline C
authors.initials: JC
authors.lastname: Blyth
authors.affiliation: European Bioenergy Research Institute, Aston University Birmingham, UK.
authors.forename: Gareth
authors.initials: G
authors.lastname: Griffiths
authors.affiliation: Birmingham Children's Hospital Birmingham, UK.
authors.forename: Deirdre
authors.initials: D
authors.lastname: Kelly
authors.affiliation: Aston Brain Centre, School of Life and Health Sciences, Aston University Birmingham, UK.
authors.forename: Joel B
authors.initials: JB
authors.lastname: Talcott
keywords: IQ; N-acetyl aspartate; cognition; cognitive spectroscopy; processing speed; proton magnetic resonance spectroscopy