Perceived Control is a Concurrent Predictor of Activity Limitations in Patients With Chronic Idiopathic Axonal Polyneuropathy

Relation of exercise and pain in patients with idiopathic distal axonal polyneuropathies

Although exercise is associated with better outcomes in patients with some peripheral neuropathies, data in idiopathic peripheral neuropathies is lacking. This study was completed to do a comprehensive data analysis about the benefits of regular exercise in a well-characterized cohort of patients with idiopathic distal, symmetrical, axonal polyneuropathy enrolled in the Peripheral Neuropathy Research Registry (PNRR) at Johns Hopkins University School of Medicine. From the patient-reported exercise habits, metabolic equivalents (METs) were calculated and the patient information was grouped into four categories. The PNRR data set, including patient reported pain, numbness, and weakness, was analyzed using the METs categories to evaluate for the benefits of exercise. We controlled for the components of metabolic syndrome including Hemoglobin A1c (HbA1c), systolic and diastolic blood pressure (BP), high density lipids (HDL) and triglyceride level, and body mass index (BMI) as defined by the Adult Treatment Panel III Guidelines. Lower METs were associated with neuropathic pain, but not with other peripheral neuropathy symptoms. Patients with IPN who exercised were less likely to have painful neuropathy independent of the average METs per week (P < .01). No significant differences were seen for patient reported numbness, weakness, or balance issues. The data suggests that patients with idiopathic neuropathy benefit from exercises even if performed on a low intensity level or less frequently, and patients are less likely to have severe pain symptoms when exercising on a regular basis.

Inducing illusory control ensures persistence when rewards fade and when others outperform us

Persisting even when the rewards of continued effort are fading is essential for achieving long-term goals, skills, and good health, alike. Yet, we often quit when things get hard. Here, we tested whether augmenting the feeling of control through external measures increases persistence under such discouraging circumstances. In two laboratory experiments, we first induced illusory control by manipulating the base-rate of positive outcomes and then tested the effect of this elevation of participants' perceived control upon their persistence under diminishing returns and in a competition against a stronger opponent. Induced illusory control significantly enhanced people's persistence in both of these motivationally challenging situations. Our findings demonstrate that motivation is dependent upon perceived, rather than objective, control, and reveal that this can be leveraged to counteract quitting behavior when things get hard, for instance in rehabilitation, physical activity interventions, or other training settings.

Using impairment and cognitions to predict walking in osteoarthritis: A series of n-of-1 studies with an individually tailored, data-driven intervention

OBJECTIVES

First, this study compares the ability of an integrated model of activity and activity limitations, the International Classification of Functioning, Disability and Health (ICF), and the Theory of Planned Behaviour (TPB) to predict walking within individuals with osteoarthritis. Second, the effectiveness of a walking intervention in these individuals is determined.

DESIGN

A series of n-of-1 studies with an AB intervention design was used.

METHODS

Diary methods were used to study four community-dwelling individuals with lower-limb osteoarthritis. Data on impairment symptoms (pain, pain on movement, and joint stiffness), cognitions (intention, self-efficacy, and perceived controllability), and walking (step count) were collected twice daily for 12 weeks. At 6 weeks, an individually tailored, data-driven walking intervention using action planning or a control cognition manipulation was delivered. Simulation modelling analysis examined cross-correlations and differences in baseline and intervention phase means. Post-hoc mediation analyses examined theoretical relationships and multiple regression analyses compared theoretical models.

RESULTS

Cognitions, intention in particular, were better and more consistent within individual predictors of walking than impairment. The walking intervention did not increase walking in any of the three participants receiving it. The integrated model and the TPB, which recognize a predictive role for cognitions, were significant predictors of walking variance in all participants, whilst the biomedical ICF model was only predictive for one participant.

CONCLUSION

Despite the lack of evidence for an individually tailored walking intervention, predictive data suggest that interventions for people with osteoarthritis that address cognitions are likely to be more effective than those that address impairment only. Further within-individual investigation, including testing mediational relationships, is warranted.

STATEMENT OF CONTRIBUTION

What is already known on this subject? N-of-1 methods have been used to study within-individual predictors of walking in healthy and chronic pain populations An integrated biomedical and behavioural model of activity and activity limitations recognizes the roles of impairment and psychology (cognitions) Interventions modifying cognitions can increase physical activity in people with mobility limitations What does this study add? N-of-1 methods are suitable to study within-individual predictors of walking and interventions in osteoarthritis An integrated and a psychological model are better predictors of walking in osteoarthritis than a biomedical model There was no support for an individually tailored, data-driven walking intervention.

Painful small fiber neuropathies

PURPOSE OF REVIEW

This article reviews the clinical features, pathophysiology, and treatment of small fiber sensory neuropathy.

RECENT FINDINGS

Neuropathic pain is prevalent among patients with peripheral neuropathies of diverse etiologies. For example, in one recent study using the sensitive Neuropathic Pain Symptom Inventory as a screening tool, neuropathic pain was reported in 94% of patients with different peripheral nervous system diseases. Neuropathic pain is frequently underrecognized or inadequately treated. Furthermore, the paucity of clinical signs with small fiber neuropathy may delay recognition of an organic process. Pain, or uncomfortable symptoms, typically results from damage to small unmyelinated nerve fibers (C fibers) or thinly myelinated nerve fibers (A delta fibers). Recent research has helped discover the location of the "pain generators" within the injured peripheral nerves. Small fiber neuropathies are relatively common in clinical practice, but until recently most of the available neurodiagnostic tests focused on large caliber nerve fibers. In the past two decades, the widespread use of quantitative sensory testing and punch skin biopsies to evaluate small caliber nerve fibers has substantially changed the neurologist's ability to diagnose and manage small fiber sensory neuropathy.

SUMMARY

Neuropathic pain from small fiber neuropathy is prevalent and is caused by a wide variety of disorders, many of which are treatable, especially if recognized early in the process.

Exploring the relationships between International Classification of Functioning, Disability and Health (ICF) constructs of Impairment, Activity Limitation and Participation Restriction in people with osteoarthritis prior to joint replacement

BACKGROUND

The International Classification of Functioning, Disability and Health (ICF) proposes three main constructs, impairment (I), activity limitation (A) and participation restriction (P). The ICF model allows for all paths between the constructs to be explored, with significant paths likely to vary for different conditions. The relationships between I, A and P have been explored in some conditions but not previously in people with osteoarthritis prior to joint replacement. The aim of this paper is to examine these relationships using separate measures of each construct and structural equation modelling.

METHODS

A geographical cohort of 413 patients with osteoarthritis about to undergo hip and knee joint replacement completed the Aberdeen measures of Impairment, Activity Limitation and Participation Restriction (Ab-IAP). Confirmatory factor analysis was used to test the three factor (I, A, P) measurement model. Structural equation modelling was used to explore the I, A and P pathways in the ICF model.

RESULTS

There was support from confirmatory factor analysis for the three factor I, A, P measurement model. The structural equation model had good fit [S-B Chi-square = 439.45, df = 149, CFI robust = 0.91, RMSEA robust = 0.07] and indicated significant pathways between I and A (standardised coefficient = 0.76 p < 0.0001) and between A and P (standardised coefficient = 0.75 p < 0.0001). However, the path between I and P was not significant (standardised coefficient = 0.01).

CONCLUSION

The significant pathways suggest that treatments and interventions aimed at reducing impairment, such as joint replacement, may only affect P indirectly, through A, however, longitudinal data would be needed to establish this.

Differential effects of self-efficacy and perceived control on intention to perform skin cancer-related health behaviours

Previous research using the Theory of Planned Behaviour (TPB) for predicting skin cancer-related health behaviours has not adequately incorporated empirical advances in the conceptualization of the perceived behavioural control (PBC) component of the theory. This study examined the role of self-efficacy and controllability for predicting sunscreen and sunbed use intentions. Five hundred and ninety young adults completed a questionnaire on beliefs and intentions regarding sunscreen and sunbed use. Analysis using confirmatory factor analysis and multiple regression supported a conceptual distinction between two PBC subcomponents: controllability and self-efficacy. While self-efficacy--but not controllability--emerged as a significant predictor of intentions to use sunscreen, the opposite pattern was observed for the prediction of intentions to use sunbeds, whereby lower controllability beliefs were associated with higher intentions. Campaigns aimed at influencing health behaviours should consider the differential effects of the components of perceived control.

The psychometric analysis of a brief and sensitive measure of perceived manageability

This study was conducted to determine the psychometric properties of the newly developed Perceived Manageability Scale (PMnac). The study was retrospective in design. Two hundred sixty-one inpatients with a spinal cord injury were recruited from The National Spinal Injuries Centre (NSIC), Stoke Mandeville Hospital, UK, as part of a convenience sample. The PMnac was developed to measure an individual's perceived manageability of their situation. The Mood Questionnaire is used to assess an individual's current mood. Both scales are part of the Needs Assessment Checklist; a psychometrically valid and reliable outcome tool and vital part of the rehabilitation pathway at the NSIC. Results indicated that out of the six items in the scale, five were found to load onto one factor. The remaining item (item number five) did not load onto this factor structure and was consequently removed from subsequent analyses. With the removal of this item, the PMnac was found to yield high internal validity correlations, internal consistency coefficients and significant sensitivity to change. The PMnac is a psychometrically reliable and valid clinical measure of an individual's perceived manageability of their situation.

MOBILE and the provision of total joint replacement

Modern joint replacements have been available for 45 years, but we still do not have clear indications for these interventions, and we do not know how to optimize the outcome for patients who agree to have them done. The MOBILE programme has been investigating these issues in relation to primary total hip and knee joint replacements, using mixed methods research.

There have been five main strands: (1) Epidemiological investigations to find out who is receiving total hip and knee replacements in the National Health Service (NHS). This has shown that there are extensive variations in different regions of the UK, with inequalities and probable inequities in the provision of these operations; (2) Epidemiological work to ascertain the population-based needs for the operations, showing under-provision of knee joint replacements, and a relative reluctance of both patients and GPs to consider knee surgery; (3) Quantitative and qualitative research into the views of patients, health care professionals and the public on the indications for, and prioritization of, total hip and knee joint replacements. This has shown lack of agreement within or between professional groups, as well as a mismatch between the views of patients and the public, and those of professionals; (4) Theoretical and experimental work on patient-related outcome measures, and the development of new instruments to assess both pain and function in people with osteoarthritis, based on the International Classification of Function, as well as a new integrated model of function; (5) Cohort studies of patients undergoing hip or knee joint replacements to find out what the determinants of good and bad outcomes are. These studies have emphasized the huge variation in disease severity at the time of surgery.

The challenge now is to use and implement our findings for maximum patient benefit.

Functioning of patients with chronic idiopathic axonal polyneuropathy (CIAP)

Although patients with Chronic Idiopathic Axonal Polyneuropathy (CIAP) report a slow deterioration of sensory and motor functions, the impact of this deterioration on daily functioning has not yet been investigated in detail. The first aim of this crosssectional study involving 56 patients with CIAP was, therefore, to assess patients’ functioning with use of the International Classification of Functioning, Disability and Health (ICF). The second aim was to find determinants of walking ability, dexterity, and autonomy. Fatigue and limited walking ability were present in most patients and differed considerably. In regression models, age, muscle strength, and fatigue together explained 63% of the variance in walking ability, which by itself explained almost 50% of the variance in patients’ autonomy indoors and outdoors (42% and 49%, respectively). Muscle strength and sensory function scores together explained 30% of the variance in dexterity scores, which in turn explained only 13% of the variance in autonomy indoors. The diminished autonomy of patients with CIAP might be improved by reducing fatigue, by means of training, and by improving walking ability.