Upper-extremity spinal reflex inhibition is reproducible and strongly related to grip force poststroke

Chetan P. Phadke, Christopher T. Robertson, Carolynn Patten

Research output: Contribution to journalArticle

Abstract

Purpose: Impaired reflex regulation is assumed to contribute to upper-extremity motor impairment poststroke; however, the relationship between reflex inhibition and motor function remains unclear. To address this question, it is first necessary to determine the reproducibility of reflex responses. The objective of this study was to establish the test-retest reliability of flexor carpi radialis H-reflex inhibition in healthy control and stroke participants and investigate the correlation between H-reflex inhibition and grip strength. Materials and methods: Eighteen persons poststroke (mean ± SD: age 63 ± 13 years; 6 ± 5 years poststroke; 13 males) and 16 healthy controls (age: 62 ± 12 years) participated. Reflex inhibition was tested on 2 separate days by conditioning the H-reflex with radial nerve stimulation at two different interstimulus intervals: 13 ms (presynaptic Ia inhibition-PSI) and 0 ms (disynaptic inhibition). Pearson's and intraclass correlation coefficients {two-way mixed model-ICC (1, 2)}, and standard error of measurement (SEM) were calculated. Results: Relative reliability (ICCs) ranged from good to excellent (0.61-0.78). SEM was low (range 10-19%, stroke; 15-20%, healthy controls). Paretic grip strength and paretic limb PSI revealed a positive correlation (r = 0.70; p < 0.0125). Disynaptic inhibition and paretic grip strength were not correlated. Conclusions: To our knowledge, this is the first study to demonstrate reproducibility of reflex inhibition in individuals poststroke. Furthermore, we quantify smallest real differences, which provide an estimate of the magnitude of effect required to determine a meaningful change, exceeding measurement error. The correlation between PSI and grip strength suggests the potential contribution of PSI to grip force production and upper-extremity motor function.

Original languageEnglish (US)
Pages (from-to)441-448
Number of pages8
JournalInternational Journal of Neuroscience
Volume125
Issue number6
DOIs
StatePublished - Jan 1 2015
Externally publishedYes

Fingerprint

Hand Strength
Upper Extremity
Reflex
H-Reflex
Reproducibility of Results
Stroke
Radial Nerve
Inhibition (Psychology)
Extremities

Keywords

  • Disynaptic inhibition
  • H-reflex
  • Presynaptic inhibition
  • Reliability
  • Stroke

ASJC Scopus subject areas

  • Neuroscience(all)

Cite this

Upper-extremity spinal reflex inhibition is reproducible and strongly related to grip force poststroke. / Phadke, Chetan P.; Robertson, Christopher T.; Patten, Carolynn.

In: International Journal of Neuroscience, Vol. 125, No. 6, 01.01.2015, p. 441-448.

Research output: Contribution to journalArticle

@article{c7ae6ee770e84631b56578d0b5e87070,
title = "Upper-extremity spinal reflex inhibition is reproducible and strongly related to grip force poststroke",
abstract = "Purpose: Impaired reflex regulation is assumed to contribute to upper-extremity motor impairment poststroke; however, the relationship between reflex inhibition and motor function remains unclear. To address this question, it is first necessary to determine the reproducibility of reflex responses. The objective of this study was to establish the test-retest reliability of flexor carpi radialis H-reflex inhibition in healthy control and stroke participants and investigate the correlation between H-reflex inhibition and grip strength. Materials and methods: Eighteen persons poststroke (mean ± SD: age 63 ± 13 years; 6 ± 5 years poststroke; 13 males) and 16 healthy controls (age: 62 ± 12 years) participated. Reflex inhibition was tested on 2 separate days by conditioning the H-reflex with radial nerve stimulation at two different interstimulus intervals: 13 ms (presynaptic Ia inhibition-PSI) and 0 ms (disynaptic inhibition). Pearson's and intraclass correlation coefficients {two-way mixed model-ICC (1, 2)}, and standard error of measurement (SEM) were calculated. Results: Relative reliability (ICCs) ranged from good to excellent (0.61-0.78). SEM was low (range 10-19{\%}, stroke; 15-20{\%}, healthy controls). Paretic grip strength and paretic limb PSI revealed a positive correlation (r = 0.70; p < 0.0125). Disynaptic inhibition and paretic grip strength were not correlated. Conclusions: To our knowledge, this is the first study to demonstrate reproducibility of reflex inhibition in individuals poststroke. Furthermore, we quantify smallest real differences, which provide an estimate of the magnitude of effect required to determine a meaningful change, exceeding measurement error. The correlation between PSI and grip strength suggests the potential contribution of PSI to grip force production and upper-extremity motor function.",
keywords = "Disynaptic inhibition, H-reflex, Presynaptic inhibition, Reliability, Stroke",
author = "Phadke, {Chetan P.} and Robertson, {Christopher T.} and Carolynn Patten",
year = "2015",
month = "1",
day = "1",
doi = "10.3109/00207454.2014.946990",
language = "English (US)",
volume = "125",
pages = "441--448",
journal = "International Journal of Neuroscience",
issn = "0020-7454",
publisher = "Informa Healthcare",
number = "6",

}

TY - JOUR

T1 - Upper-extremity spinal reflex inhibition is reproducible and strongly related to grip force poststroke

AU - Phadke, Chetan P.

AU - Robertson, Christopher T.

AU - Patten, Carolynn

PY - 2015/1/1

Y1 - 2015/1/1

N2 - Purpose: Impaired reflex regulation is assumed to contribute to upper-extremity motor impairment poststroke; however, the relationship between reflex inhibition and motor function remains unclear. To address this question, it is first necessary to determine the reproducibility of reflex responses. The objective of this study was to establish the test-retest reliability of flexor carpi radialis H-reflex inhibition in healthy control and stroke participants and investigate the correlation between H-reflex inhibition and grip strength. Materials and methods: Eighteen persons poststroke (mean ± SD: age 63 ± 13 years; 6 ± 5 years poststroke; 13 males) and 16 healthy controls (age: 62 ± 12 years) participated. Reflex inhibition was tested on 2 separate days by conditioning the H-reflex with radial nerve stimulation at two different interstimulus intervals: 13 ms (presynaptic Ia inhibition-PSI) and 0 ms (disynaptic inhibition). Pearson's and intraclass correlation coefficients {two-way mixed model-ICC (1, 2)}, and standard error of measurement (SEM) were calculated. Results: Relative reliability (ICCs) ranged from good to excellent (0.61-0.78). SEM was low (range 10-19%, stroke; 15-20%, healthy controls). Paretic grip strength and paretic limb PSI revealed a positive correlation (r = 0.70; p < 0.0125). Disynaptic inhibition and paretic grip strength were not correlated. Conclusions: To our knowledge, this is the first study to demonstrate reproducibility of reflex inhibition in individuals poststroke. Furthermore, we quantify smallest real differences, which provide an estimate of the magnitude of effect required to determine a meaningful change, exceeding measurement error. The correlation between PSI and grip strength suggests the potential contribution of PSI to grip force production and upper-extremity motor function.

AB - Purpose: Impaired reflex regulation is assumed to contribute to upper-extremity motor impairment poststroke; however, the relationship between reflex inhibition and motor function remains unclear. To address this question, it is first necessary to determine the reproducibility of reflex responses. The objective of this study was to establish the test-retest reliability of flexor carpi radialis H-reflex inhibition in healthy control and stroke participants and investigate the correlation between H-reflex inhibition and grip strength. Materials and methods: Eighteen persons poststroke (mean ± SD: age 63 ± 13 years; 6 ± 5 years poststroke; 13 males) and 16 healthy controls (age: 62 ± 12 years) participated. Reflex inhibition was tested on 2 separate days by conditioning the H-reflex with radial nerve stimulation at two different interstimulus intervals: 13 ms (presynaptic Ia inhibition-PSI) and 0 ms (disynaptic inhibition). Pearson's and intraclass correlation coefficients {two-way mixed model-ICC (1, 2)}, and standard error of measurement (SEM) were calculated. Results: Relative reliability (ICCs) ranged from good to excellent (0.61-0.78). SEM was low (range 10-19%, stroke; 15-20%, healthy controls). Paretic grip strength and paretic limb PSI revealed a positive correlation (r = 0.70; p < 0.0125). Disynaptic inhibition and paretic grip strength were not correlated. Conclusions: To our knowledge, this is the first study to demonstrate reproducibility of reflex inhibition in individuals poststroke. Furthermore, we quantify smallest real differences, which provide an estimate of the magnitude of effect required to determine a meaningful change, exceeding measurement error. The correlation between PSI and grip strength suggests the potential contribution of PSI to grip force production and upper-extremity motor function.

KW - Disynaptic inhibition

KW - H-reflex

KW - Presynaptic inhibition

KW - Reliability

KW - Stroke

UR - http://www.scopus.com/inward/record.url?scp=84931090354&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84931090354&partnerID=8YFLogxK

U2 - 10.3109/00207454.2014.946990

DO - 10.3109/00207454.2014.946990

M3 - Article

C2 - 25135282

AN - SCOPUS:84931090354

VL - 125

SP - 441

EP - 448

JO - International Journal of Neuroscience

JF - International Journal of Neuroscience

SN - 0020-7454

IS - 6

ER -