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Impairment in evoked V‐wave response during maximal muscle contraction in subjects with Parkinson's disease
Author(s) -
SilvaBatista Carla,
Mattos Eugenia,
Corcos Daniel,
David Fabian,
Kanegusuku Hélcio,
Forjaz Claudia,
Tricoli Valmor,
Roschel Hamilton,
Ugrinowitsch Carlos
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.1020.1
Subject(s) - isometric exercise , h reflex , medicine , reflex , f wave , parkinson's disease , cardiology , disease , nerve conduction velocity
Reduced descending drive to muscle, when assessed by V‐wave, is attenuated in aging. In subjects with Parkinson's disease (PD) it can be more reduced and associated with motor signs, however, it was still not investigated. Objective To compare evoked reflex at rest and during maximal voluntary isometric contraction (MVIC) of the plantar flexors in subjects with PD and age‐matched healthy controls (HC). It also investigated association between PD motor signs and maximal V wave‐to‐maximal M wave (V/M max ) ratio. Methods Evoked reflex at rest (H‐reflex and M‐wave amplitudes) and root mean square (RMS), peak torque (PT), and evoked reflex (V‐wave and M‐wave amplitudes) during MVIC were recorded in 10 subjects with PD (64.9 ± 9.4 years, 12.4 ± 5.8 disease duration, 41.8 ± 10.3 motor severity, 2.6 ± 0.4 stage of PD) and 10 HC (64.8 ± 9.3 years). The subjects with PD were assessed in the clinically “on” state. Results At rest, maximal H wave‐to‐maximal M wave (H max /M max ) ratio was not different between groups ( P =0.060) while during MVIC, RMS, PT, V‐wave, M‐wave, and V/M max ratio were lower for subjects with PD ( P <0.05). There was association between PD motor signs and V/M max ratio (r=−0.73, 95% confidence interval = −0.93 to −0.19, P =0.015). Conclusions Subjects with PD present reduced amplitude in V‐wave and impairment in V/M max ratio, which is associated with motor signs, likely due to abnormal descending drive to muscle that reflects a decrease of supraspinal activation. Support or Funding Information Financial support: FAPESP: 2013/04970‐4 and CNPq: 406609/2015‐2.