Brain N-Acetyl Aspartate and associations with cognitive impairment in alcohol dependent patients

ABSTRACT

Introduction: Chronic alcohol consumption has been observed to be associated with a range of cognitive impairments that impact on treatment management. In this spectroscopy study, we examined the association of N-Acetyl Aspartate (NAA), a marker of neuronal integrity, and cognitive impairment in alcohol dependent patients.

Method: Using in vivo proton magnetic resonance spectroscopy (¹H-MRS), we examined brain metabolite levels in 31 alcohol dependent individuals. ¹H-MRS from the parietal lobe were analyzed to yield absolute concentrations of NAA. Alcohol history, neurocognitive function including Clock Drawing Test (CDT), Mini Mental State Exam (MMSE), Trial Making Test (TMT) and Balloon Analogue Risk Task (BART) were also assessed. Covariates included concurrent medication, age and recent alcohol consumption.

Results: There were statistically significant bivariate associations between NAA and the variables age, CDT and BART (r = −.45, P = 01; r = −.53, P = .01; r = .49, P = .02) respectively) but there were no statistically significant associations with other measures of cognitive function. Controlling for age, concurrent medication and recent alcohol consumption, multiple linear regression revealed a negative association between parietal NAA (Model: F = 6.96, R² = .66, P = .001) and CDT scores (B = −.35, P = .03), a positive association with BART scores (B = .47, P = .02).

Conclusion: These results demonstrate that in alcohol dependent patients lower NAA/Cr is associated with reduced cognitive functioning and increased risk-taking.

KEYWORDS:

• Alcohol dependence
• proton magnetic resonance spectroscopy
• N-Acetyl Aspartate
• cognition
• cognitive spectroscopy

Contributions

KM contributed to study conception and design and data analysis.

JL contributed to the design of the MRS protocol and analysis.

WL contributed to patient recruitment, conducting neuroimaging sessions, data maintenance.

KC contributed to the MRS analysis.

AM contributed to elements of study design.

PH contributed to study design and interpretation of data.

All authors contributed to the writing of the manuscript and have approved the final manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This study was supported by a grant from a BMC Scanning Initiative Grant (KM).