Mult Scler Relat Disord. 2018 Mar 6;21:103-107. doi: 10.1016/j.msard.2018.03.004. [Epub ahead of print]
Adult brain volume in multiple sclerosis: The impact of paediatric onset.
Paediatric onset multiple sclerosis (POMS) is associated with reduced brain and deep grey matter volume in comparison with that in healthy controls and individuals with adult onset multiple sclerosis (AOMS). The aim of our study was to evaluate the impact of POMS on adult brain volume with adjustment for other parameters, such as disease duration.
PATIENTS AND METHODS:
We recruited 20 POMS and 40 AOMS patients and 20 healthy controls matched for age and sex. All study participants were adults at the time of inclusion in the study. All study subjects underwent brain magnetic resonance imaging (MRI) to evaluate whole brain, white matter, grey matter, cortical, and deep grey matter volumes. Clinical features, such as the Expanded Disability Status Scale (EDSS) score and disease duration, were also assessed.
Brain (p = 0.01), grey matter (p = 0.01), and deep grey matter volume (p = 0.03) was significantly lower in POMS patients than in AOMS patients, while no differences were detected in the volume of white matter or cortical grey matter. A multiple linear regression analysis showed a relationship between brain volume (dependent variable) and the independent variables age (p < 0.000) and paediatric onset (p < 0.001), while other independent variables, including disease duration, sex, and disability, were not significantly different among groups. There were significant differences in thalamic volume among POMS and AOMS patients and healthy controls.
Our data support the previous findings that POMS patients have reduced brain and deep grey matter volume, particularly thalamic volume, compared with sex- and age-matched AOMS patients and healthy controls. These findings appear to be independent of disease duration and other clinical features.
Childhood-onset or paediatric MS versus adult-onset MS in some instances is only a difference of a decade or so, but what a difference a decade makes. As far as we can see paediatric MS is very different to adult MS; for one thing it is more inflammatory than adult MS having a greater number of MS lesions and contrast enhancement. Not surprising, considering the burgeoning immune system at that age.
We know that the adult brain peaks at the age of 22, marking the start of aging. But what happens to your brain if you are hit by a neurological disorder before then?
Fenu and colleagues in this article looked at exactly this, comparing the brain volumes in paediatric onset and adult-onset MS cases. We already know that in adults brain volume loss is indicative of underlying neurodegeneration. However, paediatric onset MS cases seem to have overall smaller brain volumes, because of smaller deep grey matter volumes (particularly the thalamus). This was present even after controlling for disease duration. It is therefore conceivable that paediatric onset MS interferes with normal brain development.
A greater fraction of paediatric-onset MS cases have cognitive impairment (approximately 30%) compared to adult onset MS, particularly in intelligence (i.e. I.Q. is affected in paediatric MS) supporting the hypothesis of an effect on normal brain development (Amato et al. Paediatric multiple sclerosis: Cognition and mood, Neurology 87 (9 Suppl 2), 2016, p S82-87).