Sniff Nasal Inspiratory Pressure Research Articles

Supported exercise programme for adults with Congenital Heart Disease (SEACHange)

BackgroundCongenital heart disease (CHD) is a lifelong condition. Many patients will require repeated interventions. Long term morbidity due to heart failure, arrhythmias and recurrent hospital admissions is common. The benefits of regular exercise are well known. The aim of this study is to determine the feasibility of introducing a supported exercise programme to develop physical and psychological wellbeing in adults with CHD, living in Scotland. MethodsPatients were mainly recruited via the Adult Congenital Heart Disease (ACHD) review clinic at the Golden Jubilee National Hospital (GJNH). Participants were initially assessed using a 6-min walk test (6MWT) and stratified in to either Group 1 (n = 10) or Group 2 (n = 18). Further baseline measurements (Grip strength, Bicep strength, Quadriceps strength, and psychological measurements) were completed for both groups. Sniff Nasal Inspiratory Pressure (SNIP) was also assessed for Group 1. All measurements were repeated after 12 weeks. ResultsFor both groups 1 and 2 the majority of individuals improved upon their baseline measurements across all physical metrics (6MWT, quadriceps, bicep and grip strength). Although not achieving statistical significance individually, when combined groups 1 and 2 demonstrated a statistically significant increase in the objective measures of fitness from those measured at baseline to week 12. ConclusionsExercise in the adult congenital cardiac population is safe when patients are given guidance and structure.

Effect of nusinersen on respiratory function in paediatric spinal muscular atrophy types 1–3

IntroductionNusinersen is used in spinal muscular atrophy (SMA) to improve peripheral muscle function; however, respiratory effects are largely unknown.AimTo assess the effects of nusinersen on respiratory function in paediatric SMA...

Effects of an optimised approach to home-based respiratory care in individuals with amyotrophic lateral sclerosis: a study protocol for a randomised controlled trial

IntroductionThis study aims to investigate the effects of an optimal home-based respiratory care protocol in individuals with amyotrophic lateral sclerosis (ALS).Methods and analysisThis is a randomised, blinded controlled trial involving...

Effects of Air Stacking on Dyspnea and Lung Function in Neuromuscular Diseases

ObjectiveTo investigate whether the decrease in dyspnea in neuromuscular diseases after air stacking (AS) occurs mostly in patients with decreased inspiratory muscle force and ensuing chest wall restriction or heterogeneous ventilation across the lungs. DesignInterventional, before-after study. SettingA neurorehabilitation inpatient and outpatient center. ParticipantsFifteen consecutive adult patients affected by neuromuscular diseases (N=15). InterventionsAS treatment. Main Outcome MeasuresPatients had vital capacity (VC) and sniff nasal inspiratory pressure (SNIP) measured. We measured Borg score, oxygen saturation, and ventilation heterogeneity across the lung as estimated from the difference between respiratory resistance at 5 and 19 Hz (R5-19) with the forced oscillation technique before and 5, 30, 60, and 120 minutes after applying AS. ResultsBefore AS, Borg score was significantly related to R5-19 (r2 0.46, P<.05) but not to VC % predicted, SNIP % predicted, and time since symptom onset. After AS, average Borg score gradually decreased (P=.005), whereas inspiratory flow resistance at 5 Hz, R5-19, and inspiratory reactance at 5 Hz tended to improve, despite not reaching statistical significance. The decrease in dyspnea at 60 and 120 minutes after AS significantly correlated with baseline R5-19 (r2 0.49, P<.01 and r2 0.29, P<.05, respectively), but not with VC % predicted, SNIP % predicted, time since symptom onset, and clinical severity score for patients affected by amyotrophic lateral sclerosis. ConclusionsThese findings suggest that dyspnea in neuromuscular diseases is related to heterogeneous ventilation rather than inspiratory muscle force and/or lung volumes decrease. Restoring ventilation distribution across the lungs with AS appears to improve dyspnea.

Agreement and reliability of repeated bedside respiratory muscle strength measurements in acute and subacute stroke.

Many stroke trials include maximal inspiratory pressure (MIP), maximal expiratory pressure (MEP), and sniff nasal inspiratory pressure (SNIP) outcome measurements. However, data on agreement and reliability of repeated MIP, MEP, and SNIP measurements in acute and subacute stroke patients are scarce. This study employed a test-retest design. Eighteen patients (seven female) with mean (SD) age 59 (14.5) years were recruited from neurological wards. Median (range) time since first stroke was 50.5 (21-128) days. MIP, MEP, and SNIP were measured repeatedly in three testing sessions (S1-3) conducted within 24h and following international standards. Intra-rater agreement between testing sessions was analyzed using the Bland-Altman method. Test-retest reliability was analyzed using intra-class correlation coefficient (ICC). Association between individual measurement variability, time poststroke, and level of stroke impairment was analyzed using Spearman's rho. Mean difference and 95% limits of agreement for MIP were -0.40 (-23.02, 22.22) cmH2 O between S1 and S2, and 2.14 (-12.79, 16.99) cmH2 O between S2 and S3; for MEP, -4.56 (-29.01, 19.90) cmH2 O between S1 and S2, and 0.29 (-24.28, 24.87) cmH2 O between S2 and S3; and for SNIP, -10.56 (-38.48, 17.37) cmH2 O between S1 and S2, and -6.06 (-27.32, 15.20) cmH2 O between S2 and S3. ICCs for MIP, MEP, and SNIP were ≥0.9 throughout. There were no strong correlations between individual measurement variability and time poststroke or level of stroke impairment. MIP, MEP, and SNIP in acute and subacute stroke patients show good test-retest reliability for group averages; however, absolute agreement can vary considerably for some individuals.

Respiratory impact of a grand tour: insight from professional cycling.

The aim of this study was to evaluate the respiratory function and symptom perception in professional cyclists completing a Grand Tour (GT). Nine male cyclists completed La Vuelta or Tour de France (2018/19). At study entry, airway inflammation was measured via fractional exhaled nitric oxide (FeNO). Respiratory symptoms and pulmonary function were assessed prior to the first stage (Pre-GT), at the second rest day (Mid-GT) and prior to the final stage of the GT (Late-GT). Sniff nasal inspiratory pressure (SNIP) was assessed at pre and late-GT timepoints. Seven cyclists reported respiratory symptoms during the race (with a prominence of upper airway issues). Symptom severity increased either mid or late-GT for most cyclists. A decline in FEV1 from pre-to-mid GT (-0.27 ± 0.24l, -5.7%) (P = 0.02) and pre-to-late GT (-0.27 ± 0.13l, -5.7%) (P < 0.001) was observed. Similarly, a decline in FVC (-0.22 ± 0.17l, -3.7%) (P = 0.01) and FEF25-75 (-0.49 ± 0.34l/s, -11%) (P = 0.02) was observed pre-to-late GT. Overall, eight (89%) and six (67%) demonstrated a clinically meaningful decline (> 200ml) in FEV1 and FVC during the GT follow-up, respectively. SNIP remained unchanged pre-to-late GT (n = 5), however, a positive correlation was observed between ΔSNIP and ΔFVC (r = 0.99, P = 0.002). GT competition is associated with a high prevalence of upper respiratory symptoms and a meaningful decline in lung function in professional cyclists. Further research is now required to understand the underpinning physiological mechanisms and determine the impact on overall respiratory health and elite cycling performance and recovery.

The Benefit of Non-invasive Ventilation in Motor Neuron Disease.

Background:Motor Neuron Disease (MND) is a progressive neurodegenerative disorder leading to respiratory muscle weakness with dyspnoea, morning headaches, orthopnoea, poor concentration, unrefreshing sleep, fatigue and daytime somnolence. Respiratory failure is the primary cause of death in those with MND.Methods:Although guidelines suggest the use of non-invasive ventilation (NIV) in MND, there lacks clear guidance as to when is the optimal time to initiate NIV and which markers of respiratory muscle decline are the best predictors of prognosis. There have been a number of studies that have found a significant survival advantage to the use of NIV in MND. Similarly, in quality-of-life questionnaires, those treated with NIV tend to perform better and maintain a better quality of life for longer. Furthermore, studies also suggest that improved compliance and greater tolerance of NIV confer a survival advantage.Results and Discussion:Forced Vital Capacity (FVC) has traditionally been the main pulmonary function test to determine the respiratory function in those with MND; however, FVC may not be entirely reflective of early respiratory muscle dysfunction. Evidence suggests that sniff nasal inspiratory pressure and maximum mouth inspiratory pressure may be better indicators of early respiratory muscle decline. These measures have been shown to be easier to perform later in the disease, in patients with bulbar onset disease, and may indeed be better prognostic indicators.Conclusion:Despite ongoing research, there remains a paucity of randomised controlled data in this area. This review aims to summarise the evidence to date on these topics.

Deoxynucleoside therapy for respiratory involvement in adult patients with thymidine kinase 2-deficient myopathy

BackgroundRecessive mutations in the thymidinekinase 2 (TK2) gene cause a rare mitochondrial myopathy, frequently with severe respiratory involvement. Deoxynucleoside therapy is currently under investigation.Research questionWhat is the impact of nucleosides...

Biomechanical Impacts of Forward Head Posture on the Respiratory Function

Introduction: Forward head posture (FHP) is a very common problem among the working population. Being one of the most subconscious function in humans, respiratory function utilizes both the diaphragmand external intercostal muscles for quiet breathing. However during labored breathing, many other muscles will be recruited, and mostly these muscles have attachments in the cervical, thoracic ribcage,and even lumbar vertebrae. By the nature of attachments of these muscles on the cervical vertebra and thoracic cage, it is then plausible that FHP would affect the respiratory function.&#x0D; Methods: Thorough searches were done through international journals for the last ten years regarding the topic of FHP and its impacts to the respiratory biomechanics.&#x0D; Discussion: Previous studies have reported how prolonged FHP will result in kyphotic posture, reducing the mobility of ribcage, and modifies all respiratory muscular attachments such as sternocleidomastoids, intercostals, and to a certain extent, the diaphragm. All these result in a restrictive lung disorder, signified by reducing spirometry values, such as Forced Vital Capacity, Sniff Nasal Inspiratory Pressure, and Peak Flow Rate.&#x0D; Conclusion: Forward head posture disturb the respiratory biomechanics.

Effect of inspiratory muscle training on respiratory muscle strength and functional capacity in patients with type 2 diabetes mellitus: A randomized clinical trial.

Type 2 diabetes mellitus (T2DM) is usually associated with respiratory manifestations including inspiratory muscle weakness which affects exercise capacity. The present study aimed to determine the effect of inspiratory muscle training (IMT) on inspiratory muscle strength and exercise capacity in patients with Type 2 diabetes mellitus (T2DM). This was a randomized controlled trial in patients with type 2 diabetes mellitus with no previous cardiopulmonary or neuromuscular diseases. Patients had no back pain. Patients were randomized into interventional or placebo groups. Sniff nasal inspiratory pressure (SNIP), maximum inspiratory pressure (MIP), and six-minute walking test (6MWT) were measured at baseline and 8 weeks post incremental inspiratory muscle training. At baseline, interventional and placebo groups were similar in age, body mass index, sex inspiratory muscle strength, and exercise capacity. After 8 weeks of incremental inspiratory muscle training at 40% of MIP, the interventional group had a significant increase in the SNIP (mean difference: 18.5 ± 5.30 cm H2O vs 2.8 ± 4.8 cm H2O) and MIP (mean difference: 19.4 ± 4.3 Vs 5.4 ± 3.6 cm H2O) compared to the placebo group, respectively. The interventional group showed improvement in the 6MWT (mean difference: 70 ± 29 m vs 34 ± 24 m) compared to the placebo group, P < .05. Incremental inspiratory muscle training increased the diaphragm strength in patients with T2DM and improved exercise capacity.

Heterogeneity of predictors of nocturnal hypoventilation in amyotrophic lateral sclerosis

Objective In amyotrophic lateral sclerosis (ALS), early recognition of nocturnal hypoventilation (NH) is essential to start noninvasive ventilation (NIV), but nocturnal transcutaneous PCO2 (PtcCO2) is difficult to monitor. Usefulness of respiratory and muscular function test in the prediction of NH has been explored without distinguishing among ALS phenotypes. We evaluated cross-sectional relationships between functional tests and nocturnal PCO2, and the best predictors of NH, separately in patients with spinal and bulbar onset of ALS. Methods: ALS patients candidate to NIV were recruited. Diurnal respiratory and muscular function tests and nocturnal polysomnography with PtcCO2 monitoring were performed. NH was defined as peak PtcCO2 >49 mm Hg. Results: Thirty-six patients with spinal and 11 with bulbar onset ALS were included. Nocturnal oxygen saturation and PtcCO2, and proportion of subjects with NH were similar in each group (spinal: 50%; bulbar: 45.5%). Significant differences between groups were found in forced vital capacity (p = 0.03), maximal inspiratory pressure (p = 0.01) and sniff nasal inspiratory pressure (SNIP) (p = 0.007), but not in diurnal arterial blood gases. In the spinal group, SNIP and Base Excess (BE) independently predicted nocturnal PtcCO2 (R2 0.59, p < 0.0001). In the bulbar group only SNIP was correlated to PtcCO2, but it varied little in relationship to PtcCO2 changes. Conclusions: Respiratory and muscle function parameters are differently related to NH in ALS patients with spinal and bulbar presentation. SNIP and BE may be helpful to reveal NH in spinal patients, while in bulbar patients no respiratory or muscle function tests may reliably predict NH.

The importance of maintaining the same order of performance of lung function and SNIP tests in patients with amyotrophic lateral sclerosis

Objective: Sniff nasal inspiratory pressure (SNIP), a useful tool for the assessment of diaphragm function in patients with Amyotrophic Lateral Sclerosis (ALS), is usually performed together with lung function tests. The aim of this study was to evaluate whether SNIP results are influenced by the order of performance of the tests. Methods: 103 consecutive patients (65% males, 80% spinal onset) were recruited. The highest value of up to 10 sniffs, was recorded before (SNIPT0) and after (SNIPT1) the assessment of lung function, peak cough (PCF), and peak expiratory flow (PEF). Results: Mean and median values were respectively 31.10 and 26.00 cm H2O for SNIPT0 and 28.93 and 25.00 cm H2O for SNIPT1 (p < 0.001). The median value of (SNIPT1 − SNIPT0)/SNIPT0% was −7.10. Patients showing post lung function SNIP values above the median were included in Group 1 (51%), the others in group 2 (49%). Group 2 showed more severe baseline ventilatory restriction and reduction in PCF than Group 1. Positive direct relationships were found between SNIPT0 and SNIPT1 (coefficient β = 0.95, p < 0.001), and forced vital capacity and forced expiratory volume at one second. Conclusions: 50/103(49%) patients with ALS show a significant reduction in SNIP when assessed shortly after the performance of lung function tests. These patients suffer from more severe ventilatory restriction than patients not showing the reduction. Our findings suggest standardizing the order of respiratory tests during the follow up in order to avoid to misestimate the real strength of inspiratory muscles.

Respiratory Dysfunction and Sleep-Disordered Breathing in Children With Myasthenia Gravis.

The purpose of this study was to prospectively evaluate sleep patterns and the presence of sleep-disordered breathing in children with myasthenia gravis. We further aimed to examine the relationship between sleep and daytime respiratory function using spirometry tests including upright and supine forced vital capacity, sniff nasal inspiratory pressure, and maximal inspiratory pressure. Eleven children between 3 and 18 years old with confirmed myasthenia gravis were recruited from The Hospital for Sick Children Neuromuscular Clinic in this prospective observational study. After informed consent was obtained, patients underwent a comprehensive clinical assessment with collection of anthropometric data. Following this, all subjects performed pulmonary function tests, overnight polysomnography and completed the Epworth Sleepiness Scale questionnaire. Two of eleven children who reported no symptoms of sleep disordered breathing were diagnosed with mild to moderate obstructive sleep apnea. Pulmonary function tests showed abnormal maximal inspiratory pressure in 6 of 11 patients, whereas seated forced vital capacity as well as seated to supine forced vital capacity ratios were normal in the entire group. In our small group of pediatric myasthenia gravis subjects, there was an unexpected finding of obstructive sleep apnea in 2 of the 11 patients studied. Maximal inspiratory pressure appears to be a more sensitive method of detecting abnormalities compared to upright or seated forced vital capacity. A larger multicenter study is needed to validate our findings and to determine the impact of obstructive sleep apnea in the pediatric myasthenia gravis population as well as risk factors associated with sleep disordered breathing.

Assessment of the respiratory muscles strength at patients with chronic obstructive pulmonary disease with various forms of comorbidity

To evaluate the RM power of COPD patients with various variants of comorbidity and to determine the role of comorbidity in the development of respiratory muscle dysfunction. RM strength of 64 men with exacerbation of COPD was studied. The severity of comorbidity was assessed by the Charlson index. Depending on the prevalence of comorbidity, patients were divided into 3 groups: cardiovascular, cerebrovascular and metabolic. Maximum inspiratory (MIP) and expiratory (MEP) pressures in the oral cavity, maximum rate of pressure development (MRPD), sniff nasal inspiratory pressure (SNIP), MEP/MIP and SNIP/MIP indexes were determined with MicroRPM device (UK). Measured values of MIP, MEP and SNIP were compared with the proper ones. The most noticeable decrease of RM strength was defined in the group of patients with severe comorbidity. In case of a mild comorbidity MEP and SNIP values were 68 and 78% of the predicted values and MIP value corresponded to the personified standard. RM strength of patients with COPD depended on the clinical variant of comorbidity. Thus, in the group of patients with cardiovascular variant of comorbidity auxiliary inspiratory muscles strength decreased. In the group of patients with cerebrovascular variant of comorbidity the expiratory muscles dysfunction predominated. In the group of patients with metabolic variant of comorbidity diaphragm dysfunction predominated. The pathogenetic significance of various factors of COPD comorbidity in the development of RM dysfunction was confirmed by the results of the correlation analysis.

Dyspnea as a Fatigue-Promoting Factor in ALS and the Role of Objective Indicators of Respiratory Impairment

ContextThere is no evidence-based treatment for fatigue in amyotrophic lateral sclerosis (ALS), and identification of treatable causes determines management strategies. Although dyspnea is a key symptom of ALS and effectively treatable, it has not been sufficiently investigated whether dyspnea may be a fatigue-promoting factor. ObjectivesTo determine the level of fatigue in dyspneic ALS patients and whether fatigue is promoted by dyspnea. We further evaluated the correlation of fatigue with respiratory function tests. MethodsAbout 101 dyspneic patients and 20 matched controls completed the ALS Functional Rating Scale—Extension and the Fatigue Severity Scale. Dyspneic patients additionally completed the Dyspnea-ALS Scale and the ALS Assessment Questionnaire and underwent respiratory function tests (forced vital capacity, sniff nasal inspiratory pressure, mean inspiratory and expiratory pressure with respective relaxation rates, and blood gases). Multiple regression and correlation analyses were conducted. ResultsDyspneic patients had significantly higher fatigue scores than nondyspneic patients, and their fatigue significantly affected quality of life. Dyspnea alone explained up to 24% of the variance in fatigue. No associations were observed between fatigue and respiratory function tests. Patients with noninvasive ventilation reported significantly more dyspnea and fatigue. ConclusionFatigue is a frequent and bothersome symptom in dyspneic ALS patients. Dyspnea-related distress is, in contrast to objective indicators of respiratory impairment, a determining factor of experienced fatigue. There is an urgent need for further symptom relief beyond noninvasive ventilation. Adequate treatment of dyspnea has the potential for synergies in symptom management arising from the association between fatigue and dyspnea.

Respiratory measurements and airway clearance device prescription over one year in amyotrophic lateral sclerosis

Objective: The rates of decline in respiratory measurements, including Peak Cough Flow (PCF) have not been established in Amyotrophic Lateral Sclerosis (ALS). Additionally, optimal prescription of cough adjuncts which aim to increase cough strength are unknown. The primary aim of this study was to quantify declines in respiratory function in ALS using PCF, Sniff Nasal Inspiratory Pressure (SNIP) and Slow Vital Capacity (SVC). Secondary aims were to measure respiratory morbidity, audit the characteristics of those prescribed cough adjuncts, and compare outcomes between treated and untreated cohorts. Methods: A prospective, longitudinal, observational, cohort study evaluated respiratory measures, morbidity, and physical function in ALS patients at three monthly intervals, over one year. Patient and disease characteristics of those prescribed cough adjuncts were profiled at the time of device prescription. Results: one hundred and eight participants with mean age 62.1 ± 11.5 years participated. PCF declined rapidly at a rate of 124.8L/min/year (p < 0.001). SNIP, SVC (%predicted), and ALSFRS-R also declined significantly at rates of 18.72cmH2O, 17.49%, and 9.62 units per year respectively (p < 0.001). Thirty-two (29.6%) patients reported 56 incidences of chest infection and 21 died. Patients prescribed a cough adjunct (44.4%) had significantly lower average PCF, SNIP, SVC percent predicted, and ALSFRS-R (p < 0.001). Conclusions: This study identified a rapid rate of decline in PCF, a similar decline in SNIP, and slower declines in SVC and ALSFRS-R. Cough adjunct prescription was triggered by declining respiratory measures and recommended PCF thresholds, but also by respiratory symptoms. Chest infections were common in patients regardless of cough adjunct prescription and should be closely monitored.

What is the right moment for noninvasive ventilation in amyotrophic lateral sclerosis?

The most common cause of death in patients with amyotrophic lateral sclerosis (ALS) is respiratory failure, often in the period of 2-5 years, with a small percentage of patients surviving up to 10 years or more. The aim of the study was to evaluate the significance of pulmonary function tests in prediction of mortality and definition of indications for noninvasive mechanical ventilation (NIMV). This retrospective-prospective study was performed at the Clinic of Pulmonology, Clinical Centre of Serbia in the period from January 2015 to December 2017. Patients with diagnosis of ALS established according to El Escorial criteria were included. The study included 76 patients with ALS, 50 (65.85%) with spinal and 26 (34.2%) with bulbar form of disease. Forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1) were higher in spinal form of ALS, and the difference was statistically significant when compared to bulbar form. Form of disease, FVC < 70%, maximum inspiratory pressure (PImax) < 50 and maximum expiratory pressure (PEmax) < 50 were significant factors for survival. The patients with bulbar form of disease had 2.174 (95.0% CI: 1.261-3.747) higher risk for death. Our study points to the significance of timely application and early start of NIMV in patients with ALS as an important approach to defer functional impairment, which would mean that the criteria, in our country, for application of these devices must be changed, not only regarding the value of current functional diagnostic tests used in everyday practice in patients with ALS but also in regard to the introduction of new diagnostic tests, such as sniff nasal inspiratory pressure and/or polysomnographic testing.

Reference values of sniff nasal inspiratory pressure in healthy children

To determine reference values of sniff nasal inspiratory pressure (SNIP) in healthy children. This cross-sectional observational study included healthy children aged 6 to 11 years of both sexes. The volunteers underwent a pulmonary function test to rule out respiratory disorders. Respiratory muscle strength was measured using maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP), respectively, with MIP close to functional residual capacity (FRC) and residual volume, while MEP to total lung capacity. SNIP was performed through the nostril contralateral to the occlusion, close to FRC. Two 6-minute walk tests were performed to assess functional exercise capacity. The sample comprised 121 healthy children (62 girls); 54% presented body mass index (BMI) percentile less than 85th and 46% more than equal to 85th percentile, higher than expected. SNIP values were similar between sexes (91.1 ± 21.0 cmH2 O in girls and 87.7 ± 19.4 cmH2 O in boys; P = .36) as well as the means of lower limits of normal (56.88 cmH2 O for girls and 56.66 cmH2 O for boys). Girls presented SNIP measurements larger than those of the MIP of FRC (P < .0001), while boys presented similar mean values for both. We found a positive correlation between SNIP and BMI percentile (r = .25, P = .04) in girls, unlike boys, in whom no correlation was observed. SNIP reference values and mean lower limits of normal were defined for healthy children aged 6 to 11. BMI percentile seems to positively influence the inspiratory muscle strength measured by SNIP in girls only.

The C9orf72 expansion is associated with accelerated respiratory function decline in a large Amyotrophic Lateral Sclerosis cohort

Introduction: The C9orf72 hexanucleotide repeat expansion is causal in amyotrophic lateral sclerosis (ALS) and has a negative effect on prognosis. The C9orf72 repeat expansion has been associated with an accelerated deterioration of respiratory function and survival in a cohort of 372 Portuguese patients. Methods: Cases presenting to the Irish ALS clinic with both longitudinal occluded sniff nasal inspiratory pressure (SNIP) and C9orf72 testing were including in the study. Clinical variables and survival characteristics of these patients were collected. Joint longitudinal and time to event models were constructed to explore the longitudinal characteristics of the cohort by C9orf72 status. Results: In total, 630 cases were included, of which 58 (9.2%) carried the C9orf72 repeat expansion. Plots of the longitudinal trend after joint modelling revealed that those carrying the expansion had worse respiratory function throughout the course of their disease than those without. The ALS Functional Rating Scale-revised (ALSFRS-R) respiratory sub-score did not distinguish C9orf72 normal from expanded cases. Furthermore, modelling by site of onset and gender sub-groups revealed that this difference was greatest in male spinal onset cases. Joint models further indicated that occluded SNIP values were of prognostic importance. Conclusions: Our results confirm findings from Portugal that the C9orf72 repeat expansion is associated with accelerated respiratory function decline. Analysis via joint models indicate that respiratory function is of prognostic importance and may explain previous observations of poorer prognosis in male spinal onset patients carrying the C9orf72 expansion.

Relationship Between Respiratory Muscle Strength, Handgrip Strength, and Muscle Mass in Hospitalized Patients.

Minimal information is available to validate measurement of respiratory muscle strength (RMS) in the clinical setting. The purpose of this study was to determine the correlation between maximal inspiratory pressure (MIP), maximal expiratory pressure (MEP), and sniff nasal inspiratory pressure (SNIP) with handgrip strength (HGS) and cross sectional muscle area obtained via diagnostic abdominal computed tomography (CT). Measures of MIP, MEP, SNIP, and HGS were obtained from individuals that participated in a previously published study; individuals who had an abdominal CT completed with (±)7 days of obtaining RMS measures were included. Both RMS and HGS were measured within 48-72 hours of admission; for RMS, the highest absolute (cm H2 O) and percent predicted values were recorded, and the average of 3 HGS measurements (kg) was documented. Cross-sectional muscle area (cm2 ) at the third lumbar region was recorded. Spearman's correlation coefficient was used to assess the relationship between variables. A total of 35 participants were included. HGS was correlated to absolute MIP (rs = 0.62, rs = 0.61), MEP (rs = 0.74, rs = 0.73), and SNIP (rs = 0.58, rs = 0.54) for males and females, respectively. Crosss-sectional muscle area was correlated with absolute MIP (rs = 0.66), MEP (rs = 0.58), and SNIP (rs = 0.783) for men and absolute SNIP (rs = 0.56) among women. Measures of RMS represent a promising assessment of muscle mass and function among hospitalized patients.