title: Effects of aging on genioglossus motor units in humans.
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.
authors.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.
authors.forename: Julian P
authors.initials: JP
authors.lastname: Saboisky
authors.affiliation: Department of Systems Design Engineering, University of Waterloo, Waterloo, Canada.
authors.forename: Daniel W
authors.initials: DW
authors.lastname: Stashuk
authors.affiliation: Mathematics and Computer Science, Mount Allison University, Sackville, New Brunswick, Canada.
authors.forename: Andrew
authors.initials: A
authors.lastname: Hamilton-Wright
authors.affiliation: School of Psychological Sciences, University of Melbourne, Melbourne, Victoria, Australia.
authors.forename: John
authors.initials: J
authors.lastname: Trinder
authors.affiliation: Natus Medical Inc, Middleton, Wisconsin, United States of America.
authors.forename: Sanjeev
authors.initials: S
authors.lastname: Nandedkar
authors.affiliation: Division of Sleep Medicine, Brigham and Women's Hospital, and Harvard Medical School, Boston, Massachusetts, United States of America; University of California San Diego, La Jolla, California, United States of America.
authors.forename: Atul
authors.initials: A
authors.lastname: Malhotra
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D018482:Muscle, Skeletal / Q000502:physiology* / Q000503:physiopathology; D012119:Respiration; D020181:Sleep Apnea, Obstructive / Q000503:physiopathology; D014059:Tongue / Q000502:physiology / Q000503:physiopathology; D014851:Wakefulness / Q000502:physiology; D055815:Young Adult
references.citation: J Appl Physiol (1985). 2003 May;94(5):1849-58
references.pmid: 12514165
references.citation: J Neurol Neurosurg Psychiatry. 1977 Jun;40(6):544-54
references.pmid: 903769
references.citation: Respir Physiol Neurobiol. 2008 Jan 1;160(1):65-75
references.pmid: 17945544
references.citation: J Appl Physiol (1985). 2010 Dec;109(6):1939-49
references.pmid: 20947713
references.citation: Eur Respir J. 1997 Sep;10(9):2087-90
references.pmid: 9311508
references.citation: Acta Physiol Scand. 1954 Nov;32(2-3):200-18
references.pmid: 13228109
references.citation: Eur Respir J. 2014 Sep;44(3):685-93
references.pmid: 24833768
references.citation: Am Rev Respir Dis. 1992 Apr;145(4 Pt 1):846-52
references.pmid: 1554213
references.citation: J Physiol. 2007 May 15;581(Pt 1):291-8
references.pmid: 17317747
references.citation: Clin Anat. 2010 Oct;23(7):777-91
references.pmid: 20607833
references.citation: Am J Respir Crit Care Med. 1999 Jan;159(1):213-9
references.pmid: 9872841
references.citation: Med Eng Phys. 1999 Jul-Sep;21(6-7):389-404
references.pmid: 10624736
references.citation: Eur Respir J. 1996 Sep;9(9):1801-9
references.pmid: 8880094
references.citation: J Neurosci Methods. 2007 May 15;162(1-2):287-92
references.pmid: 17336391
references.citation: Muscle Nerve Suppl. 2002;11:S98-S102
references.pmid: 12116293
references.citation: Clin Auton Res. 2010 Jun;20(3):175-82
references.pmid: 19756828
references.citation: Psychiatry Investig. 2012 Mar;9(1):65-72
references.pmid: 22396687
references.citation: J Physiol. 2008 Sep 1;586(17):4283-94
references.pmid: 18635645
references.citation: Can J Neurol Sci. 2004 May;31(2):142-56
references.pmid: 15198438
references.citation: Am J Respir Crit Care Med. 1999 Jun;159(6):1960-6
references.pmid: 10351945
references.citation: Ann Otol Rhinol Laryngol. 2001 Aug;110(8):779-84
references.pmid: 11510738
references.citation: Respir Physiol Neurobiol. 2005 Jul 28;147(2-3):263-72
references.pmid: 16054444
references.citation: Ear Nose Throat J. 1980 Mar;59(3):94-9
references.pmid: 7371568
references.citation: Sleep. 2008 Jul;31(7):1009-17
references.pmid: 18652096
references.citation: Sleep. 2008 Apr;31(4):525-33
references.pmid: 18457240
references.citation: N Engl J Med. 1993 Apr 29;328(17):1230-5
references.pmid: 8464434
references.citation: Electroencephalogr Clin Neurophysiol. 1991 Aug;81(4):304-11
references.pmid: 1714825
references.citation: J Physiol. 2007 Nov 15;585(Pt 1):135-46
references.pmid: 17916615
references.citation: J Appl Physiol (1985). 2000 May;88(5):1831-9
references.pmid: 10797148
references.citation: J Neurol Neurosurg Psychiatry. 1971 Aug;34(4):453-60
references.pmid: 4938133
references.citation: IEEE Trans Biomed Eng. 1995 Jun;42(6):616-20
references.pmid: 7790018
references.citation: Am J Med. 2006 Jan;119(1):72.e9-14
references.pmid: 16431197
references.citation: Clin Neurophysiol. 2004 Mar;115(3):543-56
references.pmid: 15036049
references.citation: J Clin Neurophysiol. 1986 Oct;3(4):313-48
references.pmid: 3332279
references.citation: J Anat. 1958 Apr;92(2):178-88
references.pmid: 13525233
references.citation: Anat Rec. 2000 Dec 1;260(4):378-86
references.pmid: 11074403
references.citation: JAMA. 2003 May 7;289(17):2230-7
references.pmid: 12734134
references.citation: J Anat. 1938 Oct;73(Pt 1):15-30.1
references.pmid: 17104743
references.citation: IEEE Trans Biomed Eng. 1984 Feb;31(2):220-7
references.pmid: 6706351
references.citation: J Neurol Sci. 1985 May-Jun;69(1-2):67-79
references.pmid: 3159855
references.citation: Eur Respir J. 2012 Aug;40(2):386-93
references.pmid: 22241742
references.citation: Muscle Nerve. 1982 Apr;5(4):265-80
references.pmid: 7099194
references.citation: Muscle Nerve. 1982;5(9S):S135-8
references.pmid: 6302490
references.citation: Chest. 2007 Jun;131(6):1702-9
references.pmid: 17413053
references.citation: J Neuroeng Rehabil. 2010 Aug 11;7:39
references.pmid: 20701781
references.citation: Eur Respir J. 2000 May;15(5):906-10
references.pmid: 10853857
references.citation: Eur Respir J. 2003 Mar;21(3):523-9
references.pmid: 12662012
references.citation: Arch Neurol. 1962 May;6:366-73
references.pmid: 14495823
references.citation: Physiol Rev. 1980 Jan;60(1):90-142
references.pmid: 6766557
references.citation: Am J Respir Crit Care Med. 2012 Feb 1;185(3):322-9
references.pmid: 22016445
references.citation: J Neurophysiol. 2006 Apr;95(4):2213-21
references.pmid: 16306175
references.citation: Arch Intern Med. 2009 Jun 22;169(12):1147-55
references.pmid: 19546416
references.citation: Eur J Orthod. 1999 Aug;21(4):333-44
references.pmid: 10502896
references.citation: Electroencephalogr Clin Neurophysiol. 1988 Jun;69(6):561-7
references.pmid: 2453333
references.citation: Anat Rec. 2000 Nov 1;260(3):308-25
references.pmid: 11066041
references.citation: Muscle Nerve. 2008 Jul;38(1):939-40
references.pmid: 18508350
references.citation: Crit Rev Oral Biol Med. 2003;14(6):413-29
references.pmid: 14656897
references.citation: J Speech Lang Hear Res. 2001 Feb;44(1):95-107
references.pmid: 11218113
references.citation: J Neurol Neurosurg Psychiatry. 1990 Apr;53(4):331-4
references.pmid: 2341847
references.citation: J Sleep Res. 2012 Dec;21(6):718-23
references.pmid: 22906153
references.citation: Exp Neurol. 1976 Apr;51(1):160-70
references.pmid: 177304
references.citation: J Anat Physiol. 1881 Apr;15(Pt 3):382-91
references.pmid: 17231393
references.citation: Electroencephalogr Clin Neurophysiol. 1983 Jul;56(1):52-62
references.pmid: 6190633
references.citation: Semin Respir Crit Care Med. 2010 Oct;31(5):618-33
references.pmid: 20941662
references.citation: J Appl Physiol (1985). 2001 Mar;90(3):1074-82
references.pmid: 11181622
references.citation: J Physiol. 2003 Dec 1;553(Pt 2):533-44
references.pmid: 12963804
references.citation: Acta Neurol (Napoli). 1977 Jan-Feb;32(1):1-29
references.pmid: 855688
references.citation: Electroencephalogr Clin Neurophysiol. 1988 Aug;70(2):177-84
references.pmid: 2456195
references.citation: PLoS One. 2014 Mar 25;9(3):e92808
references.pmid: 24667894
references.citation: Sleep. 1990 Dec;13(6):502-11
references.pmid: 2126391
references.citation: Muscle Nerve. 1991 Sep;14(9):820-5
references.pmid: 1922175
references.citation: J Neurol Neurosurg Psychiatry. 1997 Aug;63(2):175-80
references.pmid: 9285455
references.citation: J Neurosci Methods. 2008 Mar 15;168(2):483-93
references.pmid: 18053579
references.citation: J Appl Physiol (1985). 1992 Sep;73(3):812-6
references.pmid: 1400042
references.citation: Muscle Nerve. 1989 May;12(5):382-9
references.pmid: 2725565
references.citation: Laryngoscope. 2000 Jun;110(6):1018-25
references.pmid: 10852524