Initial Neuropsychological Profile of a Series of 20 Patients with Logopenic Variant of Primary Progressive Aphasia

Background: Logopenic variant of primary progressive aphasia (LPPA) is classically considered as an isolated language disorder, but verbal short-term memory deficit induces difficulties in neuropsychological tests that are not intended to evaluate language. Objective: The aim of this study is to describe the initial symptoms and neuropsychological profiles of LPPA. Methods: A retrospective study was conducted with a series of 20 consecutive patients diagnosed with LPPA. Clinical, neuroimaging, neuropsychological, and linguistic examinations are reported. The first neuropsychological examinations (mean time between neuropsychological assessment and diagnosis: 11 months) were then compared to 20 patients with mild cognitive impairment (MCI) and 20 patients with Alzheimer's disease (AD) matched by age, gender, and education level. Results: A recent onset or aggravation of anxiety disorders was frequently reported. An unusual neuropsychological profile, different from that of AD or MCI, was observed: dissociation between verbal and visual memory performances, poor encoding performances on verbal memory tests, and preserved orientation to time, difficulties with mental calculation and fluency tasks. Biparetal abnormality and left hippocampal diaschisis was frequently observed. Asymptomatic dopaminergic depletion was observed in four patients. Conclusion: Our study identifies that de novo or recently worsening anxiety and specific neuropsychological profiles call for screening for LPPA, including a linguistic examination. Sometimes, there may be a continuum between LPPA and corticobasal syndrome.