Brain involvement in myotonic dystrophy: MRI features and their relationship to clinical and cognitive conditions

Abstract

A prospective, case‐control study was carried out on 25 patients with myotonic dystrophy (MyD) and 25 healthy subjects using brain magnetic resonance imaging (MRI). The frequency and severity of white matter hyperintense lesions (WMHL) and brain atrophy in MyD patients were compared with their clinical features and cognitive impairment using an extensive neuropsychological battery. Eighty‐four per cent of MyD patients showed WMHL, compared with 16% of controls (p<0.0001). These lesions involved all cerebral lobes, without hemispheric prevalence. Twenty‐eight per cent of MyD patients also showed particular WMHL at their temporal poles. Myotonic patients had significantly more cortical atrophy than controls. No relationship between atrophy and WMHL was found on the MRI scans. The extent of brain abnormalities (WMHL or atrophy) was not correlated to age, disease duration, physical disability or severity of neuropsychological impairment. Central nervous system abnormalities revealed by MRI appear to be an almost constant feature of MyD, but they are not found to be related to clinical or cognitive parameters. Their nature is still unclear: some of them, located at the temporal poles, seem to be characteristic of the disease, while others small, diffuse WMHLs, similar to the age related alterations revealed by MRI occurring during young and adult age in MyD patients.

Functional MRI changes in the central motor system in myotonic dystrophy type 1

“…White matter changes and cerebral atrophy have been shown [19][20][21][26][27][28][29][30][31][32][33][34]. In a morphometric study, we have shown that frontal and prefrontal cortices are among the cortical areas selectively involved in the gray matter atrophy in DM1 [24].…”

Cerebral involvement in myotonic dystrophies

“…Frontal lobe motor areas and the prefrontal cortex are involved in strategic planning tasks. Earlier reports had documented a significant impairment of frontal lobe function, 14,24 as is typical of a dysexecutive syndrome. Several authors tried to correlate neuropsychological and neuroimaging findings.…”

“…There has been inconsistency in interpreting these white matter hyperintense lesions and no general agreement as to their clinical relevance. Some authors do not find a clinical correlate to the neuroimaging profile, 14 whereas others find a correlation between neuropsychological data and the distribution and severity of white matter abnormalities. 24,45,111 We found no correlation between the degree of cerebral involvement on traditional MRI studies and cognitive and behavioral profiles.…”

“…From a neuropsychological perspective, visual-spatial deficits are detected when patients are asked to copy a complex figure while maintaining its correct intersections and angles (Rey copy and recall). There is general agreement that patients with DM1 present deficits in visual-spatial performance 14,37,71,125 because their scores on neuropsychological tests are significantly lower than in age-and educationmatched controls. Modoni et al 78 strengthened this conclusion in a recent study performed on a larger sample of patients stratified by CTG size and demonstrated that, despite small expansions, visualspatial deficits characterize the neuropsychological profile of adult patients with DM1 in contrast with the more general intellectual impairment of patients with congenital forms.…”

Brain involvement in myotonic dystrophies: neuroimaging and neuropsychological comparative study in DM1 and DM2

“…Age of disease onset ranged from 5 to 67 years (mean 37.6 ± 19.2 years), with an estimated disease duration of 16.3 ± 10.2 years. Mean educational level was 10 ± 5 years (range [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. None of the selected subjects presented a clinical history of other neurological diseases affecting muscle or cognitive functions, alcohol or drug abuse; thyreotoxicosis or diabetes were further exclusion criteria.…”