An investigation of the effects of age and stroke on implicit motor imagery as demonstrated by a hand laterality judgment test

Abstract

Background Explicit motor imagery is recommended for stroke
rehabilitation but can be difficult to practice. Hand Laterality
Judgement (HLJ) stimulates implicit motor imagery which may be
easier for stroke patients, but its benefits are unknown. Previous
studies are inconclusive and have not considered the effects of older
age.

Objectives. This thesis investigated the effects of older age and
stroke on HLJ and the effects of practising HLJ after a stroke.

Methods Three experiments were undertaken. The first compared
HLJ in twenty young, healthy participants (mean=22(2) years) with
twenty aged 60 -70 years (mean=67(3) years) and twenty-two aged
≥ 70 years (mean=77(5) years). The second compared HLJ of eleven
stroke survivors aged ≥ 60 years (mean =69 (6)) with age-matched
controls. The third examined the effects of practising HLJ in four
stroke survivors.

Main findings There were no significant differences in HLJ response
times between the young and older groups (p=.06) or between the
stroke and control group (p=.13). Both older groups were
significantly less accurate than the younger group (young group
=92%; older groups= 81%-86% p≤ .00). There were no significant
differences in accuracy between the two older groups (P=.10) or
between the stroke and control groups (p=.59). All groups engaged
in implicit motor imagery, but this was impaired by early old age.
Visuospatial imagery was impaired in later old age and by stroke.
There were no significant relationships between HLJ performance and
upper limb impairment post-stroke. There were no significant effects
of practising HLJ, but trends towards increased accuracy (d=.24) and
slower response times (d=.46).

Conclusion Stroke survivors can perform HLJ as well as similarly
aged healthy individuals. Stroke may impair visuospatial imagery, but
accuracy improves with practice. Further research is needed to
determine if there are any benefits to post-stroke upper limb
rehabilitation.

Date of Award	21 Feb 2021
Original language	English
Awarding Institution	University of Cumbria Lancaster University
Supervisor	Timothy Donovan (Supervisor), Gillian Baer (Supervisor) & Susan Dewhurst (Supervisor)