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Differentiating between adductor and abductor spasmodic dysphonia using airflow interruption
Author(s) -
Hoffman Matthew R.,
Jiang Jack J.,
Rieves Adam L.,
McElveen Kelsey A. B.,
Ford Charles N.
Publication year - 2009
Publication title -
the laryngoscope
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.181
H-Index - 148
eISSN - 1531-4995
pISSN - 0023-852X
DOI - 10.1002/lary.20572
Subject(s) - medicine , airflow , phonation , anesthesia , larynx , surgery , audiology , mechanical engineering , engineering
Objectives/Hypothesis: To measure the laryngeal resistance (R L ), subglottal pressure (P s ), and mean flow rate (MFR) of adductor (ADSD) and abductor (ABSD) spasmodic dysphonia patients using the airflow interrupter. Methods: The R L of six ABSD and seven ADSD patients was measured using the airflow interrupter, a noninvasive device designed to measure MFR and P s via mechanical balloon valve interruption. Subjects performed 10 trials at each of two intensity levels, with each trial consisting of a sustained /a/ during which phonation was interrupted for 500 ms. Laryngeal resistance was calculated as subglottal pressure divided by airflow. Results: Mean R L for the ADSD and ABSD subtypes at 65 dB were 24.78 cmH 2 O/L/s and 14.51 cmH 2 O/L/s, respectively ( P = .04). Mean R L at 70 dB were 40.02 cmH 2 O/L/s and 15.84 cmH 2 O/L/s ( P = .014). P s for the ADSD and ABSD subtypes at 65 dB were 10.23 cmH 2 O and 8.32 cmH 2 O, respectively ( P = .582). At the 70 dB level, P s were 12.39 cmH 2 O and 11.78 cmH 2 O ( P = .886). MFR for the ADSD and ABSD subtypes at 65 dB were 435 mL/s and 746 mL/s ( P = .205). Mean MFR at 70 dB were 518 mL/s and 848 mL/s ( P = .198). Conclusions: Noninvasive measurements of R L may be useful for differentiating between ADSD and ABSD. This simple objective test, which produces a quantitative output, could be used to evaluate laryngeal function in patients with spasmodic dysphonia. Laryngoscope, 2009