[Abstract+References] Does Stroke Rehabilitation Really Matter? Part A: Proportional Stroke Recovery in the Rat

Abstract

Background. In human upper-limb stroke, initial level of functional impairment or corticospinal tract injury can accurately predict the degree of poststroke recovery, independent of rehabilitation practices. This proportional recovery rule implies that current rehabilitation practices may play little or no role in brain repair, with recovery largely a result of spontaneous biological recovery processes.

Objective. The present study sought to determine if similar biomarkers predict recovery of poststroke function in rats, indicating that an endogenous biological recovery process might be preserved across mammalian species.

Methods. Using a cohort of 593 male Sprague-Dawley rats, we predicted poststroke change in pellet retrieval in the Montoya staircase-reaching task based on initial impairment alone. Stratification of the sample into “fitters” and “nonfitters” of the proportional recovery rule using hierarchical cluster analysis allowed identification of distinguishing characteristics of these subgroups.

Results. Approximately 30% of subjects were identified as fitters of the rule. These rats showed recovery in proportion to their initial level of impairment of 66% (95% CI = 62%-70%). This interval overlaps with those of multiple human clinical trials. A number of variables, including less severe infarct volumes and initial poststroke impairments distinguished fitters of the rule from nonfitters.

Conclusions. These findings suggest that proportional recovery is a cross-species phenomenon that can be used to uncover biological mechanisms contributing to stroke recovery.

References

1.	Prabhakaran, S, Zarahn, E, Riley, C. Inter-individual variability in the capacity for motor recovery after ischemic stroke. Neurorehabil Neural Repair. 2008;22:64–71. Google Scholar, Link
2.	Winters, C, van Wegen, EEH, Daffertshofer, A, Kwakkel, G. Generalizability of the proportional recovery model for the upper extremity after an ischemic stroke. Neurorehabil Neural Repair. 2015;29:614–622. Google Scholar, Link, ISI
3.	Byblow, WD, Stinear, CM, Barber, PA, Petoe, MA, Ackerley, SJ. Proportional recovery after stroke depends on corticomotor integrity. Ann Neurol. 2015;78:848–859. Google Scholar, Crossref, Medline
4.	Feng, W, Wang, J, Chhatbar, PY. Corticospinal tract lesion load: an imaging biomarker for stroke motor outcomes. Ann Neurol. 2015;78:860–870. Google Scholar, Crossref, Medline
5.	Stinear, CM, Byblow, WD, Ackerley, SJ, Smith, MC, Borges, VM, Barber, PA. Proportional motor recovery after stroke: implications for trial design. Stroke. 2017;48:795–798. Google Scholar, Crossref, Medline
6.	Smith, MC, Byblow, WD, Barber, PA, Stinear, CM. Proportional recovery from lower limb motor impairment after stroke. Stroke. 2017;48:1400–1403. Google Scholar, Crossref, Medline
7.	Winters, C, van Wegen, EEH, Daffertshofer, A, Kwakkel, G. Generalizability of the maximum proportional recovery rule to visuospatial neglect early poststroke. Neurorehabil Neural Repair. 2017;31:334–342. Google Scholar, Link
8.	Lazar, RM, Minzer, B, Antoniello, D, Festa, JR, Krakauer, JW, Marshall, RS. Improvement in aphasia scores after stroke is well predicted by initial severity. Stroke. 2010;41:1485–1488. Google Scholar, Crossref, Medline
9.	Krakauer, JW, Marshall, RS. The proportional recovery rule for stroke revisited. Ann Neurol. 2015;78:845–847. Google Scholar, Crossref, Medline
10.	Gladstone, DJ, Danells, CJ, Black, SE. The Fugl-Meyer assessment of motor recovery after stroke: a critical review of its measurement properties. Neurorehabil Neural Repair. 2002;16:232–240. Google Scholar, Link
11.	Carmichael, ST. Rodent models of focal stroke: size, mechanism, and purpose. NeuroRx. 2005;2:396–409. Google Scholar, Crossref, Medline

via Does Stroke Rehabilitation Really Matter? Part A: Proportional Stroke Recovery in the RatNeurorehabilitation and Neural Repair – Matthew Strider Jeffers, Sudhir Karthikeyan, Dale Corbett, 2018