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Effects of aging on genioglossus motor units in humans.

Saboisky JP, Stashuk DW, Hamilton-Wright A, Trinder J, Nandedkar S, Malhotra A - PLoS ONE (2014)

Bottom Line: To assess possible changes associated with aging we compared quantitative parameters related to motor unit potential morphology derived from EMG signals in a sample of older (n = 11; >55 years) versus younger (n = 29; <55 years) adults.Amplitudes of CNMACRO MUPs detected in older adults were larger by 22% (62.7±6.5 µV versus 51.3±3.0 µV; P<0.05), with areas 24% larger (160.6±18.6 µV.ms versus 130.0±7.4 µV.ms; P<0.05) than those detected in younger adults.These results confirm that remodeled motor units are present in the genioglossus muscle of individuals above 55 years, which may have implications for OSA pathogenesis and aging related upper airway collapsibility.

View Article: PubMed Central - PubMed

Affiliation: Division of Sleep Medicine, Brigham and Women's Hospital, and Harvard Medical School, Boston, Massachusetts, United States of America; Neuroscience Research Australia, Sydney, New South Wales, Australia; Prince of Wales Clinical School, Faculty of Medicine University of New South Wales, Sydney, New South Wales, Australia.

ABSTRACT
The genioglossus is a major upper airway dilator muscle thought to be important in obstructive sleep apnea pathogenesis. Aging is a risk factor for obstructive sleep apnea although the mechanisms are unclear and the effects of aging on motor unit remodeled in the genioglossus remains unknown. To assess possible changes associated with aging we compared quantitative parameters related to motor unit potential morphology derived from EMG signals in a sample of older (n = 11; >55 years) versus younger (n = 29; <55 years) adults. All data were recorded during quiet breathing with the subjects awake. Diagnostic sleep studies (Apnea Hypopnea Index) confirmed the presence or absence of obstructive sleep apnea. Genioglossus EMG signals were analyzed offline by automated software (DQEMG), which estimated a MUP template from each extracted motor unit potential train (MUPT) for both the selective concentric needle and concentric needle macro (CNMACRO) recorded EMG signals. 2074 MUPTs from 40 subjects (mean±95% CI; older AHI 19.6±9.9 events/hr versus younger AHI 30.1±6.1 events/hr) were extracted. MUPs detected in older adults were 32% longer in duration (14.7±0.5 ms versus 11.1±0.2 ms; P  =  0.05), with similar amplitudes (395.2±25.1 µV versus 394.6±13.7 µV). Amplitudes of CNMACRO MUPs detected in older adults were larger by 22% (62.7±6.5 µV versus 51.3±3.0 µV; P<0.05), with areas 24% larger (160.6±18.6 µV.ms versus 130.0±7.4 µV.ms; P<0.05) than those detected in younger adults. These results confirm that remodeled motor units are present in the genioglossus muscle of individuals above 55 years, which may have implications for OSA pathogenesis and aging related upper airway collapsibility.

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Related in: MedlinePlus

Duration of MUPs plotted versus subject age.Mean MUP duration (ms) versus age (years). The MUPs with longer durations are associated with increased age. The Pearson correlation coefficient was calculated from the mean value of all 40 subjects (r  =  0.660; P  =  0.00000359). The open black circles depict values from older control subjects while solid circles depict values from older obstructive sleep apnea subjects. The open grey circles depict values from younger control subjects while solid circles depict values from younger obstructive sleep apnea subjects.
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pone-0104572-g004: Duration of MUPs plotted versus subject age.Mean MUP duration (ms) versus age (years). The MUPs with longer durations are associated with increased age. The Pearson correlation coefficient was calculated from the mean value of all 40 subjects (r  =  0.660; P  =  0.00000359). The open black circles depict values from older control subjects while solid circles depict values from older obstructive sleep apnea subjects. The open grey circles depict values from younger control subjects while solid circles depict values from younger obstructive sleep apnea subjects.

Mentions: The selective concentric needle MUPs detected in older adults had 34% longer duration (P<0.001), with greater thickness (P<0.05), but did not have greater amplitude, area, number of phases or RIR coefficient, than those detected in younger adults (see Figures 2, 3 & 4; Table 3).


Effects of aging on genioglossus motor units in humans.

Saboisky JP, Stashuk DW, Hamilton-Wright A, Trinder J, Nandedkar S, Malhotra A - PLoS ONE (2014)

Duration of MUPs plotted versus subject age.Mean MUP duration (ms) versus age (years). The MUPs with longer durations are associated with increased age. The Pearson correlation coefficient was calculated from the mean value of all 40 subjects (r  =  0.660; P  =  0.00000359). The open black circles depict values from older control subjects while solid circles depict values from older obstructive sleep apnea subjects. The open grey circles depict values from younger control subjects while solid circles depict values from younger obstructive sleep apnea subjects.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4128697&req=5

pone-0104572-g004: Duration of MUPs plotted versus subject age.Mean MUP duration (ms) versus age (years). The MUPs with longer durations are associated with increased age. The Pearson correlation coefficient was calculated from the mean value of all 40 subjects (r  =  0.660; P  =  0.00000359). The open black circles depict values from older control subjects while solid circles depict values from older obstructive sleep apnea subjects. The open grey circles depict values from younger control subjects while solid circles depict values from younger obstructive sleep apnea subjects.
Mentions: The selective concentric needle MUPs detected in older adults had 34% longer duration (P<0.001), with greater thickness (P<0.05), but did not have greater amplitude, area, number of phases or RIR coefficient, than those detected in younger adults (see Figures 2, 3 & 4; Table 3).

Bottom Line: To assess possible changes associated with aging we compared quantitative parameters related to motor unit potential morphology derived from EMG signals in a sample of older (n = 11; >55 years) versus younger (n = 29; <55 years) adults.Amplitudes of CNMACRO MUPs detected in older adults were larger by 22% (62.7±6.5 µV versus 51.3±3.0 µV; P<0.05), with areas 24% larger (160.6±18.6 µV.ms versus 130.0±7.4 µV.ms; P<0.05) than those detected in younger adults.These results confirm that remodeled motor units are present in the genioglossus muscle of individuals above 55 years, which may have implications for OSA pathogenesis and aging related upper airway collapsibility.

View Article: PubMed Central - PubMed

Affiliation: Division of Sleep Medicine, Brigham and Women's Hospital, and Harvard Medical School, Boston, Massachusetts, United States of America; Neuroscience Research Australia, Sydney, New South Wales, Australia; Prince of Wales Clinical School, Faculty of Medicine University of New South Wales, Sydney, New South Wales, Australia.

ABSTRACT
The genioglossus is a major upper airway dilator muscle thought to be important in obstructive sleep apnea pathogenesis. Aging is a risk factor for obstructive sleep apnea although the mechanisms are unclear and the effects of aging on motor unit remodeled in the genioglossus remains unknown. To assess possible changes associated with aging we compared quantitative parameters related to motor unit potential morphology derived from EMG signals in a sample of older (n = 11; >55 years) versus younger (n = 29; <55 years) adults. All data were recorded during quiet breathing with the subjects awake. Diagnostic sleep studies (Apnea Hypopnea Index) confirmed the presence or absence of obstructive sleep apnea. Genioglossus EMG signals were analyzed offline by automated software (DQEMG), which estimated a MUP template from each extracted motor unit potential train (MUPT) for both the selective concentric needle and concentric needle macro (CNMACRO) recorded EMG signals. 2074 MUPTs from 40 subjects (mean±95% CI; older AHI 19.6±9.9 events/hr versus younger AHI 30.1±6.1 events/hr) were extracted. MUPs detected in older adults were 32% longer in duration (14.7±0.5 ms versus 11.1±0.2 ms; P  =  0.05), with similar amplitudes (395.2±25.1 µV versus 394.6±13.7 µV). Amplitudes of CNMACRO MUPs detected in older adults were larger by 22% (62.7±6.5 µV versus 51.3±3.0 µV; P<0.05), with areas 24% larger (160.6±18.6 µV.ms versus 130.0±7.4 µV.ms; P<0.05) than those detected in younger adults. These results confirm that remodeled motor units are present in the genioglossus muscle of individuals above 55 years, which may have implications for OSA pathogenesis and aging related upper airway collapsibility.

Show MeSH
Related in: MedlinePlus