Evaluation of the nation-wide implementation of ALS home monitoring & coaching: an e-health innovation for personalized care for patients with motor neuron disease.

BACKGROUND: To improve the care for patients with motor neuron disease an e-health innovation for continuous monitoring of disease progression and patients' well-being (ALS H&C) was implemented in 10 multidisciplinary rehabilitation settings. The first aim was to evaluate the implementation of ALS H&C by assessing several implementation outcomes, technology acceptance and usability of the innovation according to the end users. The secondary aim was to explore differences in these outcomes between the teams with sustainable and unsustainable implementation. METHODS: The chosen implementation strategy was a combination of the implementation process model by Grol & Wensing and a participatory action research approach. In three meetings with multidisciplinary project groups the innovation was introduced, the expected barriers/facilitators identified, and action plans to resolve each barrier developed. After a 3-month pilot phase, patients and their healthcare providers were asked to complete an online evaluation survey to assess implementation outcomes, based on Proctor's evaluation framework (i.e., acceptability, feasibility, fidelity, sustainability). Telemedicine technology acceptance was assessed according the technology acceptance model of Chau, and user experiences with the System Usability Scale (SUS). Implementation outcomes of teams with sustainable implementation (continuation after completion of the pilot phase) and unsustainable implementation (discontinuation after the pilot phase) were compared. RESULTS: The implementation outcomes from the patients' perspective (N = 71) were positive; they found ALS H&C to be an acceptable and feasible care concept. Patients' technology acceptance was high, with positive attitudes towards ALS H&C, and positive views on perceived technology control, usefulness, and ease of use. Patients rated their satisfaction with the (web) app on a scale from 1 (not satisfied at all) to 10 (very satisfied) with a 7.0 (median; IQR 1.0). Healthcare providers (N = 76) also found ALS H&C acceptable and appropriate as well, but were less positive about the feasibility and usability of ALS H&C (mean SUS 58.8 [SD 11.3]). ALS H&C has largely been implemented as intended and the implementation was sustainable in 7 teams. Teams who discontinued ALS H&C after the pilot phase (N = 2) had more fidelity issues. CONCLUSIONS: A participatory action research approach supported by theoretical approaches used in implementation science led to a sustainable implementation of ALS H&C in 7 of the participating teams. To improve implementation success, additional implementation strategies to increase feasibility, usability and fidelity are necessary. TRIAL REGISTRATION: Trial NL8542 registered at Netherlands Trial Register (trialregister.nl) on 15th April 2020.

Drug-induced sleep endoscopy: the effect of different passive maneuvers on the distribution of collapse patterns of the upper airway in obstructive sleep apnea patients.

PURPOSE: To evaluate the effect of different passive maneuvers (lateral head rotation and jaw thrust) during drug-induced sleep endoscopy (DISE) on distribution of collapse patterns at the level of velum, oropharynx, tongue base, and epiglottis (VOTE). METHODS: Retrospective, single-center cohort study. Patients diagnosed with OSA who underwent DISE between August 2016 and February 2017 were included. During DISE procedure lateral head rotation, jaw thrust and a combination of both were applied and scored by VOTE obstruction level. Also, the effect of these maneuvers was analyzed for complete concentric collapse (CCC) versus complete non-concentric collapse (CNCC) subgroups. RESULTS: Two hundred patients were included (161 male (80.5%), mean age 50.1 ± 11.7 years, median AHI 19.2 (11.7, 31.0) events/h). For lateral head rotation, significant improvement in upper airway collapse at all levels was observed, with exception of the level of the oropharynx, where an increase in obstruction was seen. Jaw thrust resulted in a significant decrease of collapse on all four VOTE levels. The CCC group responded similarly to the CNCC group when only one maneuver was applied, but the CCC group showed less improvement when both maneuvers were combined. CONCLUSIONS: This study gives new insights into the changes in distribution of collapse patterns when passive maneuvers are applied during DISE. Jaw thrust and lateral head rotation gave improvement of obstruction mostly in line with previous research. The CNCC and CCC groups responded similarly to application of a single maneuver, but there was a significant difference found when both maneuvers were combined.

Towards a prediction model for drug-induced sleep endoscopy as selection tool for oral appliance treatment and positional therapy in obstructive sleep apnea.

PURPOSE: To evaluate the effect of different passive maneuvers on upper airway patency during drug-induced sleep endoscopy (DISE) compared to recent literature on treatment outcomes of positional therapy (PT), oral appliance therapy (OAT), and combined treatment in obstructive sleep apnea (OSA) patients. METHODS: A retrospective, single-center cohort study including a consecutive series of 200 OSA patients. All patients underwent DISE with and without manually performed jaw thrust and lateral head rotation by using the VOTE classification. The effect of these maneuvers were analyzed by using the sum VOTE score comparing non-positional (NPP) and positional OSA patients (PP). RESULTS: Two hundred patients were included (80.5% male) with a mean age of 50.1 ± 11.7 years, a BMI of 27.0 ± 3.1 kg/m2, and a median AHI of 19.2 events per hour. Forty-four percent of the patients were NPP; of the remaining 56%, 34% was diagnosed with supine isolated and 66% with supine predominant POSA. Manually performed jaw thrust showed a reduction of sum VOTE score of 66.7% in all subgroups. The effect of lateral head rotation was a reduction of 33.3% in NPP and supine predominant PP and 50% in supine isolated PP. Combining these maneuvers a reduction of more than 75% was seen in all patients. CONCLUSIONS: The present model leaves room for improvement. The effect of manually performed jaw thrust is greater and the effect of lateral head rotation alone is less than what was expected compared to recent literature on treatment outcome of OAT, PT, and combined treatment.

Subjective effects of the sleep position trainer on snoring outcomes in position-dependent non-apneic snorers.

PURPOSE: To evaluate the effect of a new-generation positional device, the sleep position trainer (SPT), in non-apneic position-dependent snorers. METHODS: Non-apneic position-dependent snorers with an apnea-hypopnea index (AHI) < 5 events/h were included between February 2015 and September 2016. After inclusion, study subjects used the SPT at home for 6 weeks. The Snore Outcome Survey (SOS) was filled out by the subjects at baseline and after 6 weeks, and at the same time, the Spouse/Bed Partner Survey (SBPS) was filled out by their bed partners. RESULTS: A total of 36 participants were included and 30 completed the study. SOS score improved significantly after 6 weeks from 35.0 ± 13.5 to 55.3 ± 18.6, p < 0.001. SBPS score also improved significantly after 6 weeks from 24.7 ± 16.0 versus 54.5 ± 25.2, p < 0.001. The severity of snoring assessed with a numeric visual analogue scale (VAS) by the bed partner decreased significantly from a median of 8.0 with an interquartile range (IQR) of [7.0-8.5] to 7.0 [3.8-8.0] after 6 weeks (p = 0.004). CONCLUSIONS: Results of this study indicate that positional therapy with the SPT improved several snoring-related outcome measures in non-apneic position-dependent snorers. The results of this non-controlled study demonstrate that this SPT could be considered as an alternative therapeutic option to improve sleep-related health status of snorers and their bed partners.

Feedback learning and behavior problems after pediatric traumatic brain injury.

BACKGROUND: Feedback learning is essential for behavioral development. We investigated feedback learning in relation to behavior problems after pediatric traumatic brain injury (TBI). METHOD: Children aged 6-13 years diagnosed with TBI (n = 112; 1.7 years post-injury) were compared with children with traumatic control (TC) injury (n = 52). TBI severity was defined as mild TBI without risk factors for complicated TBI (mildRF- TBI, n = 24), mild TBI with ⩾1 risk factor for complicated TBI (mildRF+ TBI, n = 51) and moderate/severe TBI (n = 37). The Probabilistic Learning Test was used to measure feedback learning, assessing the effects of inconsistent feedback on learning and generalization of learning from the learning context to novel contexts. The relation between feedback learning and behavioral functioning rated by parents and teachers was explored. RESULTS: No evidence was found for an effect of TBI on learning from inconsistent feedback, while the moderate/severe TBI group showed impaired generalization of learning from the learning context to novel contexts (p = 0.03, d = -0.51). Furthermore, the mildRF+ TBI and moderate/severe TBI groups had higher parent and teacher ratings of internalizing problems (p's ⩽ 0.04, d's ⩾ 0.47) than the TC group, while the moderate/severe TBI group also had higher parent ratings of externalizing problems (p = 0.006, d = 0.58). Importantly, poorer generalization of learning predicted higher parent ratings of externalizing problems in children with TBI (p = 0.03, ß = -0.21) and had diagnostic utility for the identification of children with TBI and clinically significant externalizing behavior problems (area under the curve = 0.77, p = 0.001). CONCLUSIONS: Moderate/severe pediatric TBI has a negative impact on generalization of learning, which may contribute to post-injury externalizing problems.

Impact of contractures on daily functioning in adolescents with spinal muscular atrophy: a qualitative study.

PURPOSE: Exploring the impact of contractures in adolescents and young adults (AYA) with spinal muscular atrophy (SMA) on daily functioning and participation and the impact of received contracture management. METHODS: We included 14, non-ambulant AYA with SMA types 2/3 (10 females and 4 males), aged 16-30 years. Interviews focused on two topics: perceived impact of contractures on daily functioning and of previous contracture management. We used inductive thematic analysis for interview analysis. RESULTS: In general, participants experienced muscle weakness to be more of a hindrance than contractures; they had adapted to their contractures over time. Participants considered contracture treatment useful when goals were meaningful and realistic. Participants mentioned that their perspective on contracture management would change in light of a promise of improved motor function due to disease-modifying treatment. CONCLUSION: Despite the relatively low impact of contractures in comparison to the loss of muscle strength, non-ambulant AYA with SMA should be informed on the potential impact of contractures and benefits and potential adverse effects of their management. This information can support the shared decision-making process. While respecting individual choices, allows for incorporating interventions into daily life and the promotion of daily functioning and participation when children with SMA are growing up.

The variability of the perceived impact of contractures in non-ambulant adolescents and young adults with spinal muscular atrophy (SMA) underscores the need for individualized assessment and contracture management based on discussions about challenges, benefits and burden.In the treatment plan for contracture management in SMA it is important to take into account: 1) that adolescents often experienced physiotherapy as additional comfort, with less feeling of stiffness, and 2) that most perceived orthosis and standers as unnecessary and burdensome as contracture management.Clinicians should consider postural management in an early stage given the improved prognosis on motor development of children with SMA.Clinicians should monitor and revisit treatment goals, benefits and adverse effects on a regular basis as part of the shared goal-setting and decision-making in contracture management for children with SMA.

Interobserver agreement on MRI evaluation of patients with cervical radiculopathy.

AIM: To evaluate the interobserver agreement on magnetic resonance imaging (MRI) evaluation of herniated discs, spondylotic neuroforaminal stenosis, and root compression in patients with recent onset cervical radiculopathy and in addition, to assess the added value of disclosure of clinical information to interobserver agreement. MATERIALS AND METHODS: The MRI images of 82 patients with less than 1 month of symptoms and signs of cervical radiculopathy were evaluated independently by two neuroradiologists who were unaware of clinical findings. MRI analysis was repeated after disclosure of clinical information. Interobserver agreement was calculated using kappa statistics. RESULTS: The kappa score for evaluation of herniated discs and of spondylotic foramen stenosis was 0.59 and 0.63, respectively. A kappa score of 0.67 was found for the presence of root compression. After disclosure of clinical information kappa scores increased slightly: from 0.59 to 0.62 for the detection of herniated discs, from 0.63 to 0.66 for spondylotic foramen stenosis, and from 0.67 to 0.76 for root compression. CONCLUSION: Interobserver reliability of MRI evaluation in patients with cervical radiculopathy was substantial for root compression, with or without clinical information. Agreement on the cause of the compression, i.e., herniated disc or spondylotic foraminal stenosis, was lower.

Implementation and evaluation of an e-health innovation for personalized care for patients with amyotrophic lateral sclerosis (ALS): protocol for a participatory action research study.

BACKGROUND: In the absence of a cure for amyotrophic lateral sclerosis (ALS), a progressive neurodegenerative disease, treatment consists of symptomatic management by a multidisciplinary healthcare team and is mainly aimed at optimizing patients' quality of life. Because the course of the disease is often erratic and varies between patients, it is imperative for patients with ALS to be closely monitored. E-health innovations that can monitor disease progression remotely have great potential to tailor the care to the needs of individual patients with ALS. Therefore, the e-health innovation "ALS Home-monitoring and Coaching" was developed employing a user-centered design process and implemented at the University Medical Center Utrecht, the Netherlands in 2017. Because ALS Home-monitoring and Coaching was shown to be feasible and well received by patients and healthcare professionals at University Medical Centre Utrecht, we aim to implement this e-health innovation nationwide, starting with 10 ALS care teams in different rehabilitation settings spread across the Netherlands. METHODS: This research focuses on the implementation process and the user experiences with ALS Home-monitoring and Coaching of both patients and healthcare professionals. We will use a participatory action research approach, with the stakeholders involved in all stages of the implementation process. The implementation process model of Grol and Wensing was used to structure and support planning, execution and evaluation of the implementation strategy. The expected barriers and facilitators will be explored and identified in focus group settings using the Theoretical Domains Framework. After that, each team will develop their own action plan with strategies for how to resolve each barrier. The teams will include 5-10 ALS patients with whom they will test their implementation plan and provide care with ALS Home-monitoring and Coaching for approximately 3 months. Afterwards, the implementation and the user experiences will be evaluated with digital surveys based on the evaluation framework of Proctor (e.g., acceptability, adoption, appropriateness). DISCUSSION: Using implementation theories, this study will provide inside in factors influencing implementation outcomes and strategies that can be used to overcome barriers. This will enhance our understanding of how to successfully implement e-health innovations in multidisciplinary care in rehabilitation settings. TRIAL REGISTRATION: Trial NL8542 registered at Netherlands Trial Register (trialregister.nl) on 15th April 2020.

Degenerative cervical radiculopathy: diagnosis and conservative treatment. A review.

Degenerative cervical radiculopathy: clinical diagnosis and conservative treatment. A review. To provide a state-of-the-art assessment of diagnosis and non-surgical treatment of degenerative cervical radiculopathy a literature search for studies on epidemiology, diagnosis including electrophysiological examination and imaging studies, and different types of conservative treatment was undertaken. The most common causes of cervical root compression are spondylarthrosis and disc herniation. Diagnosis is made mainly on clinical grounds, although there are no well-defined criteria. Provocative tests like the foraminal compression test are widely used but not properly evaluated. The clinical diagnosis of degenerative cervical radiculopathy can be confirmed by magnetic resonance imaging. The role of electromyography is mainly to rule out other conditions. Cervical radiculopathy is initially treated conservatively, although no treatment modality has been evaluated in a randomized controlled trial. Degenerative cervical radiculopathy: diagnosis and conservative treatment. A review.

Relative value of clinical variables, bicycle ergometry, rest radionuclide ventriculography and 24 hour ambulatory electrocardiographic monitoring at discharge to predict 1 year survival after myocardial infarction.

The relative value of predischarge clinical variables, bicycle ergometry, radionuclide ventriculography and 24 hour ambulatory electrocardiographic monitoring for predicting survival during the first year in 351 hospital survivors of acute myocardial infarction was assessed. Discriminant function analysis showed that in patients eligible for stress testing the extent of blood pressure increase during exercise slightly improved the predictive accuracy beyond that of simple clinical variables (history of previous myocardial infarction, persistent heart failure after the acute phase of infarction and use of digitalis at discharge), whereas radionuclide ventriculography and 24 hour electrocardiographic monitoring did not. The predictive value for mortality was 12% with clinical variables alone and 15% with the stress test added. Radionuclide ventriculography and 24 hour electrocardiographic monitoring were slightly additive to clinical information in the whole group of patients independent of the eligibility for stress testing (predictive value for mortality 24% with clinical variables alone and 26% with radionuclide ejection fraction and 24 hour electrocardiographic monitoring added). It is concluded that the appropriate use of simple clinical variables and stress testing is sufficient for risk stratification in postinfarction patients, whereas radionuclide ventriculography and 24 hour electrocardiographic monitoring should be limited to patients not eligible for stress testing.

Change in physical mobility over 10 years in post-polio syndrome.

Post-polio syndrome is characterised by progressive muscle weakness and other symptoms which can limit physical mobility. We assessed the rate of decline in mobility over 10 years in relation to strength decline; and investigated potential predictors for the rate of decline of walking capacity, a measure of mobility, in 48 patients with post-polio syndrome and proven quadriceps dysfunction at baseline. Average walking capacity and self-reported physical mobility declined over 10 years, by 6 and 14%, respectively. Concomitantly people lost an average of 15% of isometric quadriceps strength. Significantly more people used walking aids offering greater support at follow-up. Notably, there was much individual variation, with 18% of participants losing a substantial amount of walking capacity (27% decline) and concomitant self-reported physical mobility (38% decline). Loss of quadriceps strength only explained a small proportion of the variance of the decline in walking capacity (R = 11%) and the rate of decline could not be predicted from baseline values for strength, walking capacity, self-reported physical mobility or basic demographics. The individual variability, yet lack of predictive factors, underscores the need for personally tailored care based on actual functional decline in patients with post-polio syndrome.

Elevated plasma inflammatory mediators in post-polio syndrome: No association with long-term functional decline.

A key feature of post-polio syndrome (PPS) is progressive loss of muscle strength. In other chronic diseases systemic inflammation has been linked to muscle wasting. In this study plasma TNF-α, IL-6, IL-8, and leptin levels were significantly increased in PPS-patients compared to healthy controls. There was however no association between these raised systemic levels of inflammatory mediators and long-term decline in quadriceps strength or other clinical parameters. In conclusion, there is evidence for systemic inflammation in PPS, yet the relationship with clinical deterioration remains tenuous.

Prediction of mortality during the first year after acute myocardial infarction from clinical variables and stress test at hospital discharge.

The predictive value of a predischarge symptom-limited stress test was studied in 405 consecutive survivors of acute myocardial infarction (AMI). Three hundred patients performed bicycle ergometry; 105 could not perform it. Among these latter 105 patients, the stress test was contraindicated in 43 because of angina or heart failure and in 62 because of noncardiac limitations. One-year survival was 44% in the "cardiac-limited" group (19 of 43) and 92% in the "non-cardiac-limited" group (57 of 62). One-year survival among the patients who performed an exercise test at discharge was 93% (280 out of 300). The best stress test predictor of mortality by univariate analysis was the extent of blood pressure (BP) increase: 42 +/- 24 mm Hg in 280 survivors vs 21 +/- 14 mm Hg in 20 nonsurvivors (p less than 0.001). Among the 212 patients in whom BP increased 30 mm Hg or more, mortality was 3% (n = 6), while it was 16% (n = 14) among the 88 patients in whom BP increased less than 30 mm Hg. Angina, ST changes and arrhythmias were not as predictive. Stepwise discriminant function analysis showed inadequate BP increase to be an independent predictor of mortality. A high-risk group can be identified at discharge on clinical grounds in patients unable to perform a stress test, whereas intermediate- and low-risk groups can be identified by the extent of BP increase during exercise.

Effect of fatigue on maximal power output at different contraction velocities in humans.

The effect of fatigue as a result of a standard submaximal dynamic exercise on maximal short-term power output generated at different contraction velocities was studied in humans. Six subjects performed 25-s maximal efforts on an isokinetic cycle ergometer at five different pedaling rates (60, 75, 90, 105, and 120 rpm). Measurements of maximal power output were made under control conditions [after 6 min of cycling at 30% maximal O2 uptake (VO2max)] and after fatiguing exercise that consisted of 6 min of cycling at 90% VO2max with a pedaling rate of 90 rpm. Compared with control values, maximal peak power measured after fatiguing exercise was significantly reduced by 23 +/- 19, 28 +/- 11, and 25 +/- 11% at pedaling rates of 90, 105, and 120 rpm, respectively. Reductions in maximum peak power of 11 +/- 8 and 14 +/- 8% at 60 and 75 rpm, respectively, were not significant. The rate of decline in peak power during the 25-s control measurement was least at 60 rpm (5.1 +/- 2.3 W/s) and greatest at 120 rpm (26.3 +/- 13.9 W/s). After fatiguing exercise, the rate of decline in peak power at pedaling rates of 105 and 120 rpm decreased significantly from 21.5 +/- 9.0 and 26.3 +/- 13.9 W/s to 10.0 +/- 7.3 and 13.3 +/- 6.9 W/s, respectively. These experiments indicate that fatigue induced by submaximal dynamic exercise results in a velocity-dependent effect on muscle power. It is suggested that the reduced maximal power at the higher velocities was due to a selective effect of fatigue on the faster fatigue-sensitive fibers of the active muscle mass.

Propelling efficiency of front-crawl swimming.

In this study the propelling efficiency (ep) of front-crawl swimming, by use of the arms only, was calculated in four subjects. This is the ratio of the power used to overcome drag (Pd) to the total mechanical power (Po) produced including power wasted in changing the kinetic energy of masses of water (Pk). By the use of an extended version of the system to measure active drag (MAD system), Pd was measured directly. Simultaneous measurement of O2 uptake (VO2) enabled the establishment of the relationship between the rate of the energy expenditure (PVO2) and Po (since when swimming on the MAD system Po = Pd). These individual relationships describing the mechanical efficiency (8-12%) were then used to estimate Po in free swimming from measurements of VO2. Because Pd was directly measured at each velocity studied by use of the MAD system, ep could be calculated according to the equation ep = Pd/(Pd + Pk) = Pd/Po. For the four top class swimmers studied, ep was found to range from 46 to 77%. Total efficiency, defined as the product of mechanical and propelling efficiency, ranged from 5 to 8%.

Tuberculin skin test reactions by time of reading among Dutch travellers.

SETTING: Five travel and TB control clinics in The Netherlands. OBJECTIVE: To assess the variation of skin test reactions between different days of reading. DESIGN: Cohort study of non-BCG-vaccinated travellers. Mantoux skin test data were analysed for associations between time interval between administration and reading and reaction size. RESULTS: There were no significant differences in reaction size to 1 TU PPD between readings at day 3 or 4, either for pre-travel (n = 1004) or post-travel (n = 577) tests, before (P = 0.990 and 0.210, respectively) or after exclusion of 0 mm reactions (P = 0.330 and 0.474). Time intervals were not different for reaction sizes of 0, 1-9 or > or = 10 mm (P = 0.826 and 0.306). There were also no significant associations for simultaneous tests with a sensitin of Mycobacterium scrofulaceum. CONCLUSIONS: Tuberculin skin tests can be read on day 3 or 4, without compromising their validity.

Asymptomatic QTc prolongation associated with quetiapine fumarate overdose in a patient being treated with risperidone.

We report a patient who ingested a 2000-mg overdose of quetiapine fumarate (Seroquel). Her maintenance medications also included risperidone, venlafaxine, topiramate, and clonazepam. On presentation, she was drowsy, but had no other significant CNS signs and no cardiac symptoms or abnormal physical signs. Approximately 2 h after the quetiapine ingestion, an electrocardiogram (ECG) showed normal sinus rhythm at 95 beats/min with a corrected QT (QTc) interval of 537 ms (upper limit of normal = 440 ms). Plasma quetiapine concentration at that time was 1800 ng/ml. Continuous ECG monitoring for the subsequent 18 h did not reveal any episode of ventricular tachycardia. A 12-lead ECG 18 h post-overdose was normal with a QTc interval of 401 ms and the corresponding plasma quetiapine concentration was 160 ng/ml. She made an uneventful medical recovery from the toxic ingestion. This case suggests that when patients overdose on quetiapine while taking therapeutic doses of risperidone, such overdoses, even if not massive, can cause considerable QTc interval prolongation. We recommend that quetiapine overdose patients undergo continuous ECG monitoring for 12-18 h post-ingestion.

Critical illness polyneuropathy: a summary of the literature on rehabilitation outcome.

PURPOSE: To evaluate the available literature on outcome of critical illness polyneuropathy (CIP) and to identify rehabilitation problems. METHODS OF STUDY SELECTION: A literature search in electronic databases. Primary articles on outcome in CIP using the classification of ICIDH or Quality of Life were enrolled in this study. Because of the types of study design, the lack of information regarding validity and the variability, a quantitative analysis was not possible. Instead, the overall results were evaluated in a qualitative approach. RESULTS: In the literature minimal attention was given to the rehabilitation aspects and long-term outcome of patients with CIP. Outcome measures were mainly used on the level of impairments and in lesser extent on the level of disabilities. One year after the onset of CIP, muscle weakness and decreased sensory function were frequently observed. Reported functional disabilities were dependency in Activities of Daily Living (ADL) and walking disabilities. CONCLUSION: The specific course and long-term outcome of CIP remains unclear. Research on the course and long-term functional outcome in CIP is necessary in order to identify rehabilitation problems and to formulate treatment strategies specifically directed towards the outcome of CIP.

Loss of motor unit size and quadriceps strength over 10 years in post-polio syndrome.

OBJECTIVE: To investigate whether strength decline in post-polio syndrome (PPS) results from excessive distal axonal degeneration of enlarged motor units. METHODS: We assessed changes over 10 years in isometric quadriceps strength, mean motor unit action potential (MUAP) size, root mean squared (RMS) amplitude, and level of interference (LOI) in 47 patients with PPS and 12 healthy controls, using high density surface EMG. At baseline, all patients had symptomatic quadriceps dysfunction, evidenced by transmission defects on single-fibre EMG. RESULTS: MU size and strength declined significantly by 20% and 15%, respectively in patients with PPS. Those with the largest initial MU sizes exhibited the greatest losses of mean MU size (27%) and proportional decreases in quadriceps strength (23%). Initial strength, change in LOI and change in RMS amplitude together explained 35% of the variability in strength changes in patients. MU size of controls did not change, although they lost 29% strength. CONCLUSIONS: MU size and strength declined concomitantly in a homogeneous cohort of patients with PPS and quadriceps dysfunction. SIGNIFICANCE: This long term follow-up study provides evidence that size diminution of enlarged MUs combined with a reduced number of active MUs contributes to the gradual strength decline in PPS.