Assessing Working Memory in Mild Cognitive Impairment with Serial Order Recall

Article type: Research Article

Authors: Emrani, Sheina^a | Libon, David J.^{a; *} | Lamar, Melissa^b | Price, Catherine C.^c | Jefferson, Angela L.^d | Gifford, Katherine A.^d | Hohman, Timothy J.^d | Nation, Daniel A.^e | Delano-Wood, Lisa^{f; g} | Jak, Amy^{f; g} | Bangen, Katherine J.^{f; g} | Bondi, Mark W.^{f; g} | Brickman, Adam M.^h | Manly, Jennifer^h | Swenson, Rodneyⁱ | Au, Rhoda^j | on behalf of the Consortium for Clinical and Epidemiological Neuropsychological Data Analysis (CENDA)

Affiliations: [a] Departments of Geriatrics, Gerontology and Psychology, New Jersey Institute for Successful Aging, Rowan University-School of Osteopathic Medicine, Stratford, NJ, USA | [b] Department of Behavioral Sciences and the Rush Alzheimer’s Disease Center, Rush University Medical Center, Chicago, IL, USA | [c] Department of Clinical and Health Psychology, University of Florida, Gainesville, FL, USA | [d] Vanderbilt Memory and Alzheimer’s Center, Vanderbilt University Medical Center, Nashville, TN, USA | [e] Department of Psychology, University of Southern California, Los Angeles, CA, USA | [f] VA San Diego Healthcare System, San Diego, CA, USA | [g] Department of Psychiatry, University of California, San Diego, San Diego, CA, USA | [h] Department of Neurology, Taub Institute for Research on Alzheimer’s Disease and the Aging Brain, College of Physicians and Surgeons, Columbia University, New York, NY, USA | [i] University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, USA | [j] Department of Neurology, Boston University School of Medicine, Boston, MA, USA

Correspondence: [*] Correspondence to: David J. Libon, PhD, Department of Geriatrics and Gerontology and Department of Psychology, New Jersey Institute for Successful Aging, Rowan University - School of Osteopathic Medicine, 42 East Laurel Rd, Suite 1800, Stratford, NJ, 08084, USA. Tel.: +1 856 566 6787; Fax: +1 856 566 2804; E-mail: libon@rowan.edu.

Abstract: Background:Working memory (WM) is often assessed with serial order tests such as repeating digits backward. In prior dementia research using the Backward Digit Span Test (BDT), only aggregate test performance was examined. Objective:The current research tallied primacy/recency effects, out-of-sequence transposition errors, perseverations, and omissions to assess WM deficits in patients with mild cognitive impairment (MCI). Methods:Memory clinic patients (n = 66) were classified into three groups: single domain amnestic MCI (aMCI), combined mixed domain/dysexecutive MCI (mixed/dys MCI), and non-MCI where patients did not meet criteria for MCI. Serial order/WM ability was assessed by asking participants to repeat 7 trials of five digits backwards. Serial order position accuracy, transposition errors, perseverations, and omission errors were tallied. Results:A 3 (group)×5 (serial position) repeated measures ANOVA yielded a significant group×trial interaction. Follow-up analyses found attenuation of the recency effect for mixed/dys MCI patients. Mixed/dys MCI patients scored lower than non-MCI patients for serial position 3 (p < 0.003) serial position 4 (p < 0.002); and lower than both group for serial position 5 (recency; p < 0.002). Mixed/dys MCI patients also produced more transposition errors than both groups (p < 0.010); and more omissions (p < 0.020), and perseverations errors (p < 0.018) than non-MCI patients. Conclusions:The attenuation of a recency effect using serial order parameters obtained from the BDT may provide a useful operational definition as well as additional diagnostic information regarding working memory deficits in MCI.

Keywords: Boston process approach, digit span, executive functions, mild cognitive impairment, serial order, working memory

DOI: 10.3233/JAD-170555

Journal: Journal of Alzheimer's Disease, vol. 61, no. 3, pp. 917-928, 2018