Neuropsychological Profile in the C9ORF72 Associated Behavioral Variant Frontotemporal Dementia

Article type: Research Article

Authors: Suhonen, Noora-Maria^{a; b} | Haanpää, Ramona M.^c | Korhonen, Ville^{d; e} | Jokelainen, Jari^{f; g} | Pitkäniemi, Anni^a | Heikkinen, Anna-Leena^a | Krüger, Johanna^a | Hartikainen, Päivi^h | Helisalmi, Seppo^{c; h} | Hiltunen, Mikko^{h; i} | Hänninen, Tuomo^h | Remes, Anne M.^{a; b; c; h; *}

Affiliations: [a] Medical Research Center, Oulu University Hospital, Oulu, Finland | [b] Research Unit of Clinical Neuroscience, Neurology, University of Oulu, Oulu, Finland | [c] Institute of Clinical Medicine - Neurology, University of Eastern Finland, Kuopio, Finland | [d] Institute of Clinical Medicine - Neurosurgery, University of Eastern Finland, Kuopio, Finland | [e] Department of Neurosurgery, Kuopio University Hospital, Kuopio, Finland | [f] Center for Life Course Health Research, University of Oulu, Oulu, Finland | [g] Unit of Primary Health Care, Oulu University Hospital, Oulu, Finland | [h] Department of Neurology, Kuopio University Hospital, Kuopio, Finland | [i] Institute of Biomedicine, University of Eastern Finland, Kuopio, Finland

Correspondence: [*] Correspondence to: Prof. Anne M. Remes, MD, PhD, Institute of Clinical Medicine, Neurology, University of Eastern Finland, P.O. Box 1627, 70211 Kuopio, Finland. Tel.: +358 44 7174655; Fax: +358 17 172305; E-mail: [email protected].

Abstract: While the C9ORF72 expansion is a major cause of behavioral variant frontotemporal dementia (bvFTD), little is known of the resultant cognitive profile. Our aim was to characterize the neuropsychological profile of the C9ORF72 associated bvFTD. We contrasted structured neuropsychological assessments of the C9ORF72 expansion carrier bvFTD patients (n = 26) with non-carrier bvFTD patients (n = 47) and those with Alzheimer’s disease (AD) (n = 47). As compared to the non-carrier bvFTD patients, the C9ORF72 expansion carriers performed at a higher level in an immediate verbal memory test while showing poorer phonemic verbal fluency. Additionally, the expansion carriers committed more errors in the Stroop test and the Alternating S task relative to the non-carriers. Finally, while the AD patients outperformed both bvFTD patient groups in working memory, their performance was more impaired in episodic memory tasks relative to the bvFTD groups. We conclude that bvFTD patients carrying the C9ORF72 expansion may display more pronounced executive deficits together with less severe verbal memory impairment as compared to their non-carrier bvFTD counterparts. Knowledge of the specific neuropsychological features associated with the C9ORF72 related bvFTD may aid in the early diagnosis of the disease as well as in targeting genetic testing.

Keywords: Alzheimer’s disease, C9ORF72, frontotemporal dementia, frontotemporal lobar degeneration, genetics, neuropsychological tests, progressive aphasia, semantic dementia

DOI: 10.3233/JAD-161142

Journal: Journal of Alzheimer's Disease, vol. 58, no. 2, pp. 479-489, 2017