Neuropsychological Assessment Should Always be Considered in Myotonic Dystrophy Type 2

Abstract

Objectives and background: Myotonic Dystrophies (DM) are hereditary, multisystem, slowly progressive myopathies that also affect the central nervous system. In contrast to the well-established cognitive profile of Myotonic Dystrophy Type 1 (DM1), only few studies investigated cognitive dysfunction in Myotonic Dystrophy Type 2 (DM2), and their findings are inconsistent. We have therefore performed a formal comprehensive review of available studies in DM2 to identify the most commonly affected cognitive domains. Methods: An advanced search was conducted on PubMed with the terms "myotonic dystrophy type 2" AND "cognitive deficits", "cognitive", "cognition", "neuropsychological", "neurocognitive", "neurobehavioral" in all fields. All available original research articles ( 13) and 1 case study, 14 in total, were included and thoroughly studied. Results:Most research studies indicate primary cognitive deficits in executive functions (dysexecutive syndrome), memory (short term nonverbal, verbal episodic memory), visuo-spatial/constructivemotor functions and attention while language is rarely reported to be affected. Cognitive profile is associated with brain abnormalities in several secondary and high-order cortical and subcortical regions and associative white matter tracts based on the few neuroimaging and/or multimodal studies.The limited sample size of DM2 patients is the most prominent limitation on current literature. Conclusions:The multifaceted profile of cognitive deficits highlights the need for routine neuropsychological evaluation in DM2 that could unveil patients' strengths and impairments at baseline and to be carefully monitored over time.

Executive Dysfunction, Social Cognition Impairment, and Gray Matter Pathology in Myotonic Dystrophy Type 2: A Pilot Study

“…Executive Dysfunction and GM Changes in DM2 Theodosiou et al 14 there is a paucity of neuropsychological studies of individuals with DM2 (Theodosiou et al, 2021).…”

“…Existing multimodal studies have also explored the association between neuropsychological impairments and radiologic findings (Theodosiou et al, 2021). Cognitive flexibility was linked to the periaqueductal, midbrain, thalamus, parahippocampal gyrus, and anterior cingulate.…”

“…Executive impairment with accompanied frontostriatal dysfunction has been consistently described in DM2 studies based on a variety of neuropsychological measures appraising different executive processes (Chen et al, 2018;Gaul et al, 2006;Minnerop et al, 2011;Peric et al, 2015Peric et al, , 2017aPeric et al, , 2017bRadovanović et al, 2016;Romeo et al, 2010). tive impairment on DM2, please see Theodosiou et al [2021]; for a description of each test, the reader is referred to Lezak et al [2012]).…”

“…DM1 has been investigated extensively with regard to cognitive impairments and cerebral changes, but the literature regarding DM2 is sparse in that regard. The few available DM2 studies have identified executive impairment (eg, decision-making, planning, divided attention and attentional control, interference, alertness with and without warning signal, verbal fluency with change of categories, conceptual reasoning, set shifting, working memory), Executive Dysfunction and GM Changes in DM2 Theodosiou et al 5 impaired episodic memory (eg, verbal and nonverbal short-term memory, verbal learning, verbal and visuospatial long-term memory), and impaired visuospatial functions (eg, spatial visualization ability, visuospatial/constructional dexterity) as cognitive impairments (Meola et al, 2003;Peric et al, 2017b), but existing studies are inconsistent due to differences in the neuropsychological domains that they assessed (Theodosiou et al, 2021).…”

“…Although the ascertainment of cognitive changes in individual patients may have important ramifications for multidisciplinary management, formal neuropsychological testing often is not available, and no DM-specific neuropsychological screening tools currently exist (Theodosiou et al, 2021). More broadly, the characterization of DM2-associated cognitive profiles may have implications for guideline development, planning of multidisciplinary interventions, and generation of best practice recommendations.…”