title: Ultrasound for assessment of diaphragm in ALS.
abstract: OBJECTIVE
  To evaluate the correlation between diaphragm thickness assessed by ultrasound (US) with respiratory function tests and the diaphragm motor responses, in patients with amyotrophic lateral sclerosis (ALS).
  
  
  METHODS
  42 consecutive ALS patients were studied (11 with bulbar-onset), excluding patients with marked orofacial paresis. Investigation included: revised ALS functional rating scale (ALSFRS-R), forced vital capacity (FVC), maximal voluntary ventilation (MVV), maximal inspiratory (MIP) and expiratory (MEP) pressures, nasal inspiratory pressure during sniff (SNIP); peak-to-peak amplitude of the diaphragmatic motor response to phrenic nerve stimulation (Diaphragm-CMAP), diaphragmatic thickness measured by ultrasound during maximal inspiration and during maximal expiration. Patients were analysed in bulbar or spinal subgroups. Correlations and multiple linear regression models were studied.
  
  
  RESULTS
  The mean age at disease onset was 58.4 ± 11.1 years and with a mean disease duration of 17.8 ± 13.6 months. Ultrasound studies of diaphragm thickness in full inspiration correlated with diaphragm CMAP in the whole population and in spinal-onset patients; and were similar in the two groups. Multiple linear modelling showed that FVC, SNIP and MVV were dependent on the change of thickness (p=0.001, 0.001 and 0.020, respectively) and that MIP and MEP were related to diaphragm CMAP p=0.003 and p=0.025, respectively).
  
  
  CONCLUSIONS
  Diaphragm thickness correlates with Diaphragm-CMAP, except in bulbar-onset patients. Respiratory tests are dependent on both diaphragm thickness and Diaphragm-CMAP.
  
  
  CONCLUSIONS
  US thickness of the diaphragm correlates with the number of functional motor units as assessed by the phrenic nerve motor amplitude.
authors.affiliation: Institute of Physiology, Instituto de Medicina Molecular, Faculty of Medicine, University of Lisbon, Portugal.
authors.forename: Susana
authors.initials: S
authors.lastname: Pinto
authors.affiliation: Institute of Physiology, Instituto de Medicina Molecular, Faculty of Medicine, University of Lisbon, Portugal.
authors.forename: Pedro
authors.initials: P
authors.lastname: Alves
authors.affiliation: Institute of Physiology, Instituto de Medicina Molecular, Faculty of Medicine, University of Lisbon, Portugal.
authors.forename: Bernardo
authors.initials: B
authors.lastname: Pimentel
authors.affiliation: Institute of Physiology, Instituto de Medicina Molecular, Faculty of Medicine, University of Lisbon, Portugal; Department of Neurology, Royal London Hospital, Queen Mary University of London, London, UK; Department of Neuroscience, Royal London Hospital, Queen Mary University of London, London, UK.
authors.forename: Michael
authors.initials: M
authors.lastname: Swash
authors.affiliation: Institute of Physiology, Instituto de Medicina Molecular, Faculty of Medicine, University of Lisbon, Portugal; Department of Neurosciences, Hospital de Santa Maria-CHLN, Lisbon, Portugal. Electronic address: mamedemg@mail.telepac.pt.
authors.forename: Mamede
authors.initials: M
authors.lastname: de Carvalho
mesh_terms: D000328:Adult; D000368:Aged; D000690:Amyotrophic Lateral Sclerosis / Q000000981:diagnostic imaging* / Q000503:physiopathology; D003964:Diaphragm / Q000000981:diagnostic imaging* / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010791:Phrenic Nerve / Q000000981:diagnostic imaging / Q000503:physiopathology; D012129:Respiratory Function Tests / Q000379:methods; D014463:Ultrasonography
keywords: Amyotrophic lateral sclerosis; Diaphragm; Phrenic nerve; Respiratory tests; Ultrasound