title: Single-Unit Muscle Sympathetic Nerve Activity Reflects Sleep Apnea Severity, Especially in Severe Obstructive Sleep Apnea Patients.
abstract: Obstructive sleep apnea syndrome (OSAS) is associated with augmented sympathetic nerve activity, as assessed by multi-unit muscle sympathetic nerve activity (MSNA). However, it is still unclear whether single-unit MSNA is a better reflection of sleep apnea severity according to the apnea-hypopnea index (AHI). One hundred and two OSAS patients underwent full polysomnography and single- and multi-unit MSNA measurements. Univariate and multivariate regression analysis were performed to determine which parameters correlated with OSAS severity, which was defined by the AHI. Single- and multi-unit MSNA were significantly and positively correlated with AHI severity. The AHI was also significantly correlated with multi-unit MSNA burst frequency (r = 0.437, p < 0.0001) and single-unit MSNA spike frequency (r = 0.632, p < 0.0001). Multivariable analysis revealed that SF was correlated most significantly with AHI (T = 7.27, p < 0.0001). The distributions of multiple single-unit spikes per one cardiac interval did not differ between patients with an AHI of <30 and those with and AHI of 30-55 events/h; however, the pattern of each multiple spike firing were significantly higher in patients with an AHI of >55. These results suggest that sympathetic nerve activity is associated with sleep apnea severity. In addition, single-unit MSNA is a more accurate reflection of sleep apnea severity with alternation of the firing pattern, especially in patients with very severe OSAS.
authors.affiliation: Department of Disease Control and Homeostasis, Graduate School of Medical Science, Kanazawa University Kanazawa, Japan.
authors.forename: Takuto
authors.initials: T
authors.lastname: Hamaoka
authors.affiliation: Department of Disease Control and Homeostasis, Graduate School of Medical Science, Kanazawa University Kanazawa, Japan.
authors.forename: Hisayoshi
authors.initials: H
authors.lastname: Murai
authors.affiliation: Department of Disease Control and Homeostasis, Graduate School of Medical Science, Kanazawa University Kanazawa, Japan.
authors.forename: Shuichi
authors.initials: S
authors.lastname: Kaneko
authors.affiliation: Department of Disease Control and Homeostasis, Graduate School of Medical Science, Kanazawa University Kanazawa, Japan.
authors.forename: Soichiro
authors.initials: S
authors.lastname: Usui
authors.affiliation: Department of Disease Control and Homeostasis, Graduate School of Medical Science, Kanazawa University Kanazawa, Japan.
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Okabe
authors.affiliation: Department of Disease Control and Homeostasis, Graduate School of Medical Science, Kanazawa University Kanazawa, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Tokuhisa
authors.affiliation: Department of Disease Control and Homeostasis, Graduate School of Medical Science, Kanazawa University Kanazawa, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kato
authors.affiliation: Department of Disease Control and Homeostasis, Graduate School of Medical Science, Kanazawa University Kanazawa, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Furusho
authors.affiliation: Kanazawa Municipal Hospital Kanazawa, Japan.
authors.forename: Yu
authors.initials: Y
authors.lastname: Sugiyama
authors.affiliation: Kanazawa Municipal Hospital Kanazawa, Japan.
authors.forename: Yasuto
authors.initials: Y
authors.lastname: Nakatsumi
authors.affiliation: Kanazawa Municipal Hospital Kanazawa, Japan.
authors.forename: Shigeo
authors.initials: S
authors.lastname: Takata
authors.affiliation: Department of Disease Control and Homeostasis, Graduate School of Medical Science, Kanazawa University Kanazawa, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Takamura
keywords: apnea-hypopnea index; microneurography; muscle sympathetic nerve activity; single-unit recordings; sleep apnea syndromes