Chronic Stroke Sensorimotor Impairment Is Related to Smaller Hippocampal Volumes: An ENIGMA Analysis
Authors: Zavaliangos‐Petropulu Artemis , Lo Bethany , Donnelly Miranda R. , Schweighofer Nicolas , Lohse Keith , Jahanshad Neda , Barisano Giuseppe , Banaj Nerisa , Borich Michael R. , Boyd Lara A. , Buetefisch Cathrin M. , Byblow Winston D. , Cassidy Jessica M. , Charalambous Charalambos C. , Conforto Adriana B. , DiCarlo Julie A. , Dula Adrienne N. , Egorova‐Brumley Natalia , Etherton Mark R. , Feng Wuwei , Fercho Kelene A. , Geranmayeh Fatemeh , Hanlon Colleen A. , Hayward Kathryn S. , Hordacre Brenton , Kautz Steven A. , Khlif Mohamed Salah , Kim Hosung , Kuceyeski Amy , Lin David J. , Liu Jingchun , Lotze Martin , MacIntosh Bradley J. , Margetis John L. , Mohamed Feroze B. , Piras Fabrizio , Ramos‐Murguialday Ander , Revill Kate P. , Roberts Pamela S. , Robertson Andrew D. , Schambra Heidi M. , Seo Na Jin , Shiroishi Mark S. , Stinear Cathy M. , Soekadar Surjo R. , Spalletta Gianfranco , Taga Myriam , Tang Wai Kwong , Thielman Gregory T. , Vecchio Daniela , Ward Nick S. , Westlye Lars T. , Werden Emilio , Winstein Carolee , Wittenberg George F. , Wolf Steven L. , Wong Kristin A. , Yu Chunshui , Brodtmann Amy , Cramer Steven C. , Thompson Paul M. , Liew Sook‐Lei 
Published: May 2022

Background
Persistent sensorimotor impairments after stroke can negatively impact quality of life. The hippocampus is vulnerable to poststroke secondary degeneration and is involved in sensorimotor behavior but has not been widely studied within the context of poststroke upper‐limb sensorimotor impairment. We investigated associations between non‐lesioned hippocampal volume and upper limb sensorimotor impairment in people with chronic stroke, hypothesizing that smaller ipsilesional hippocampal volumes would be associated with greater sensorimotor impairment.

Methods and Results

Cross‐sectional T1‐weighted magnetic resonance images of the brain were pooled from 357 participants with chronic stroke from 18 research cohorts of the ENIGMA (Enhancing NeuoImaging Genetics through Meta‐Analysis) Stroke Recovery Working Group. Sensorimotor impairment was estimated from the FMA‐UE (Fugl‐Meyer Assessment of Upper Extremity). Robust mixed‐effects linear models were used to test associations between poststroke sensorimotor impairment and hippocampal volumes (ipsilesional and contralesional separately; Bonferroni‐corrected,
P
<0.025), controlling for age, sex, lesion volume, and lesioned hemisphere. In exploratory analyses, we tested for a sensorimotor impairment and sex interaction and relationships between lesion volume, sensorimotor damage, and hippocampal volume. Greater sensorimotor impairment was significantly associated with ipsilesional (
P
=0.005; β=0.16) but not contralesional (
P
=0.96; β=0.003) hippocampal volume, independent of lesion volume and other covariates (
P
=0.001; β=0.26). Women showed progressively worsening sensorimotor impairment with smaller ipsilesional (
P
=0.008; β=−0.26) and contralesional (
P
=0.006; β=−0.27) hippocampal volumes compared with men. Hippocampal volume was associated with lesion size (
P
<0.001; β=−0.21) and extent of sensorimotor damage (
P
=0.003; β=−0.15).

Conclusions
The present study identifies novel associations between chronic poststroke sensorimotor impairment and ipsilesional hippocampal volume that are not caused by lesion size and may be stronger in women.