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Searching for the neural basis of reserve against memory decline: intellectual enrichment linked to larger hippocampal volume in multiple sclerosis
Author(s) -
Sumowski J. F.,
Rocca M. A.,
Leavitt V. M.,
Riccitelli G.,
Sandry J.,
DeLuca J.,
Comi G.,
Filippi M.
Publication year - 2016
Publication title -
european journal of neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.881
H-Index - 124
eISSN - 1468-1331
pISSN - 1351-5101
DOI - 10.1111/ene.12662
Subject(s) - hippocampal formation , atrophy , hippocampus , cognitive reserve , neuroscience , medicine , psychology , brain size , magnetic resonance imaging , multiple sclerosis , audiology , cognition , psychiatry , cognitive impairment , radiology
Background and purpose Active engagement in intellectually enriching activities (e.g. reading, hobbies) builds ‘reserve’ against memory decline in elders and persons with multiple sclerosis ( MS ), but the neural basis for this protective influence of enrichment is unknown. Herein the neuroanatomical basis of reserve against memory decline in MS patients is investigated. Methods Relapse‐onset MS patients ( N = 187) underwent 3.0 T magnetic resonance imaging of the brain to quantify T2 lesion volume (T2 LV ) and normalized volumes of total brain, total white, total grey (using SIENAX ) and thalamus, caudate, putamen, pallidum, amygdala and hippocampus (using FIRST ). Patients completed a survey quantifying their engagement in early life intellectual enrichment (i.e. reading, hobbies). Verbal and visuospatial episodic memory was assessed with neuropsychological tasks in a representative subsample ( N = 97). Results Controlling for demographics and T2 LV , intellectual enrichment was specifically linked to larger normalized hippocampal volume ( r p = 0.213, P = 0.004), with no link to other brain volumes/structures. Moreover, greater intellectual enrichment moderated/attenuated the negative relationship between normalized total brain volume (i.e. overall cerebral atrophy) and normalized hippocampal volume (i.e. hippocampal atrophy; P = 0.001) whereby patients who engaged in more early life intellectual enrichment better maintained hippocampal volume in the face of worse overall cerebral atrophy. Finally, the link between greater intellectual enrichment and better memory was partially mediated through larger hippocampal volume. Conclusions These findings support larger hippocampal volume as one key component of the neuroanatomical basis of reserve against memory decline in MS . These findings are consistent with previous literature on experience‐dependent neuroplasticity within the hippocampus.