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dc.contributor.authorMcHugh, John C
dc.contributor.authorReilly, Richard B
dc.contributor.authorConnolly, Sean
dc.date.accessioned2012-02-01T10:34:27Z
dc.date.available2012-02-01T10:34:27Z
dc.date.issued2012-02-01T10:34:27Z
dc.identifier.citationClin Neurophysiol. 2011 Oct;122(10):2081-8. Epub 2011 Apr 21.en_GB
dc.identifier.issn1872-8952 (Electronic)en_GB
dc.identifier.issn1388-2457 (Linking)en_GB
dc.identifier.pmid21511529en_GB
dc.identifier.doi10.1016/j.clinph.2011.03.020en_GB
dc.identifier.urihttp://hdl.handle.net/10147/207668
dc.description.abstractOBJECTIVES: The purpose of this study was to build a large reference database of excitability measures in normal subjects and to examine the effects of age, sex, and BMI. METHODS: One hundred and five healthy subjects had median motor nerve excitability testing performed at the wrist using the automated threshold-tracking program, QTRAC. Statistical linear regression was used to explore relationships between nerve excitability and the independent variables. RESULTS: The main effect of age is a reduced superexcitability. Lesser effects are flattening of the normalized stimulus response curve and reduction in threshold change following strong hyperpolarizing currents. Females have lower thresholds than males and small but significant differences in voltage-gated potassium channel (KCNQ) mediated properties (late subexcitability, accommodation half time, and threshold undershoot following depolarizing electrotonus), as well as a small increase in superexcitability. BMI has no influence on nerve excitability data and does not explain sex-related differences in threshold. CONCLUSIONS: Age and sex have few and small effects on excitability parameters. SIGNIFICANCE: The expression of nodal KCNQ channels appears to be greater in females. Age-related increases in subexcitability may be attributable to changes in the muscle fibre and not the nerve.
dc.language.isoengen_GB
dc.subject.meshAdulten_GB
dc.subject.meshAgeden_GB
dc.subject.meshAged, 80 and overen_GB
dc.subject.meshAging/*physiologyen_GB
dc.subject.mesh*Body Mass Indexen_GB
dc.subject.meshEvoked Potentials, Motor/*physiologyen_GB
dc.subject.meshFemaleen_GB
dc.subject.meshHumansen_GB
dc.subject.meshMaleen_GB
dc.subject.meshMedian Nerve/*physiologyen_GB
dc.subject.meshMiddle Ageden_GB
dc.subject.meshPotassium Channels, Voltage-Gated/physiologyen_GB
dc.subject.mesh*Sex Characteristicsen_GB
dc.titleExamining the effects of age, sex, and body mass index on normative median motor nerve excitability measurements.en_GB
dc.contributor.departmentDepartment of Clinical Neurophysiology, St. Vincent's University Hospital, Elm, Park, Dublin 4, Ireland. drjohnmchugh@ireland.comen_GB
dc.identifier.journalClinical neurophysiology : official journal of the International Federation of, Clinical Neurophysiologyen_GB
dc.description.provinceLeinster
html.description.abstractOBJECTIVES: The purpose of this study was to build a large reference database of excitability measures in normal subjects and to examine the effects of age, sex, and BMI. METHODS: One hundred and five healthy subjects had median motor nerve excitability testing performed at the wrist using the automated threshold-tracking program, QTRAC. Statistical linear regression was used to explore relationships between nerve excitability and the independent variables. RESULTS: The main effect of age is a reduced superexcitability. Lesser effects are flattening of the normalized stimulus response curve and reduction in threshold change following strong hyperpolarizing currents. Females have lower thresholds than males and small but significant differences in voltage-gated potassium channel (KCNQ) mediated properties (late subexcitability, accommodation half time, and threshold undershoot following depolarizing electrotonus), as well as a small increase in superexcitability. BMI has no influence on nerve excitability data and does not explain sex-related differences in threshold. CONCLUSIONS: Age and sex have few and small effects on excitability parameters. SIGNIFICANCE: The expression of nodal KCNQ channels appears to be greater in females. Age-related increases in subexcitability may be attributable to changes in the muscle fibre and not the nerve.


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