THE CHARACTERISTICS OF RESPIRATORY FUNCTION IN PATIENTS WITH ALS. Yoshimi Matsuo*1; Noriyuki Kamata1; Gouichi Hashida1; Satoru Inoue1; Kazuo Abe2,1 1. Unit of Physical Therapy, Osaka University Hospital, Suita, Osaka, Japan; 2. Department of Neurology, Osaka University, Graduate School of Medicine, Suita, Osaka, Japan PURPOSE: The characteristics of respiratory function in patients with ALS may be important for understanding their prognoses and for interventional physical therapy. BACKGROUNDS/SIGNIFICANCE: Respiratory function is a cardinal factor for determining prognosis of patients with ALS and is considered to be partially trainable. Thus, we consider that characteristics of respiratory function in patients with ALS may be important for interventional physical therapy. SUBJECTS: 50 patients with ALS, 23 females and 27 males, with an average age of 60.8 (range 34-78) were recruited. These patients were diagnosed according to the El Escorial criteria and have been trained in the rehabilitation department in Osaka University hospital. The average ALS duration was 20.8months (range 1month- 81months). According to the site of onset, we divided 34 patients (13 females and 21 males) into limb onset (LO) group and 16 patients (10 females and 6 males) into bulbar onset (BO) group. According to the duration of disease, we also divided 25 patients (12 females and 13 males) with shorter duration (up to 16 months) into SD group and 25 patients (11 females and 14 males) with longer duration (over 16 months) into LD group. METHODS AND MATERIALS: Respiratory functions were evaluated in the sitting position. We measured vital capacity (VC), forced vital capacity (FVC), FVC percent predicted (%FVC), tidal volume (TV), forced expiratory volume in 1 second (FEV1), (FEV1/FVC)100 (FEV1%), maximum expiratory flow at 50%VC (V50), maximum expiratory flow at 25%VC (V25), V50/V25. V50/V25 has been used as a predict factor for the existence of airway obstruction. All measurements were conducted using a device (Autospirometer System 7; Minato Medical Science; Osaka, Japan). ANALYSES: For statistical analysis, unpaired-t test with one or two tailed test was adapted. P values <0.05 were considered significant. All statistical analyses were done by a computational software (Dr. SPSS 2, version 11.0.1J; SPSS; Chicago, IL). RESULTS: All measured respiratory functions are denoted in Table. Overall, respiratory functions in patients with ALS were impaired. %FVC, FEV1% and TV were not significantly different between patients in LO and in BO. V50/V25 in patients in BO was significantly smaller than that in patients in LO (p<0.05, one tailed test). %FVC, FEV1% and V50/V25 were not significantly different between patients in SD and in LD. TV in patients in SD was significantly larger than that in patients in LD (p<0.05, two tailed test). Investigating effect of duration, we divided patients in LO into two groups: patients with leg onset with short duration (LOSD) and patients with leg onset with long duration (LOLD). FEV1% and TV in patients in LOSD were significantly larger than those in patients in LOLD (p<0.05, one tailed test). %FVC and V50/V25 were not significantly different between LOSD and LOLD. We also divided patients in BO into two groups: patients with bulbar onset with short duration (BOSD) and patients with bulbar onset with long duration (BOLD). There are no significant difference between BOSD and BOLD concerning FVC, FEV1%, V50/V25 and TV. Investigating effect of site of onset, we divided patients in SD into two groups: patients with short duration with leg onset (SDLO) and patients with bulbar onset with short duration (SDBO). There are no significant difference between SDLO and SDBO concerning FVC, FEV1%, V50/V25 and TV. We also divided patients in LD into two groups: patients with long duration with leg onset (LDLO) and patients with long duration with bulbar onset (LDBO). There are no significant difference between LDLO and LDBO concerning FVC, FEV1%, V50/V25 and TV. V50/V25 is a marker of the obstruction in the peripheral airway disease. The average of V50/V25 in LO was significantly high that might indicate expiratory muscle weakness in patients with limb onset. Considering significant difference concerning FEV1% and TV comparing between LOSD and LOLD, this expiratory muscle weakness may deteriorate along with disease progression. CONCLUSIONS: Patient with ALS with limb onset may have progressive expiratory muscle weakness in their disease process. Interventional physical therapy to compensate expiratory muscle weakness is needed to improve prognoses of patient with ALS. FUNDING SOURCE: None. KEYWORDS: ALS, respiratory function, spirometry, onset type, disease duration %FVC, FEV1%, V50/V25 and TV in ALS patients unpaired-t test: p*; statistical significance p<0.05 Copyright 2009 by the American Physical Therapy Association. Requests for reprints should be directed to the corresponding author of the article. Educators, students, and other academic customers may receive permission to reprint copyrighted material from Physical Therapy (ISSN 1538-6724) by contacting the Copyright Clearance Center Inc, 222 Rosewood Dr, Danvers, MA 01923. Other types of customers who want permission to reprint should contact the APTA Editorial Office, Attn: Physical Therapy.