Minimal clinically important difference of the King's Parkinson's disease Pain Scale.

OBJECTIVE: Pain is a common and debilitating symptom of Parkinson's disease (PD) and has no specific treatment. King's Parkinson's disease Pain Scale (KPPS) is the only specific scale for pain measurement in PD with established psychometric properties. The minimal clinically important difference (MCID) of KPPS, an important parameter for the design and interpretation of therapeutic interventions, has not yet been measured. The aim of our study was to assess the MCID of KPPS. METHODS: Two hundred and seven PD patients were evaluated by KPPS before and after receiving the intervention. The Clinical Global Impression of Improvement Scale was used as an anchor, and a Receiver Operating Characteristic (ROC) curve was used to determine the optimal MCID cut-off point for KPPS. The distribution-based approach applied one-third standard deviation (SD), 0.5 SD, and one standard error of measurement (SEM) of the total score of KPPS to determine the MCID. RESULTS: The MCID achieved from the ROC curve was 3 points (sensitivity: 74.4%; specificity: 81.9%). For the distribution-based method, the MCIDs corresponding to 0.3 SD, 0.5 SD, and one SEM were 5.65, 9.41, and 2.54 points, respectively. CONCLUSION: KPPS is a valid scale for measuring pain in PD with demonstrable MCID. IMPLICATIONS FOR REHABILITATIONThe King's Parkinson's disease Pain Scale (KPPS) is a valid scale for measuring pain in patients with Parkinson's disease (PD) with demonstrable minimal clinically important difference (MCID).The MCID obtained in the current study will assist clinicians and researchers when interpreting KPPS change score to determine clinically meaningful changes of pain in both PD progression and response to interventions.

Apathy exacerbates postural control impairments in stroke survivors: The potential effects of cognitive dual-task for improving postural control.

Apathy is a stressor and debilitating common condition for both stroke survivors and their caregivers. However, its effects on the postural control of these patients have not yet been investigated. Improved postural stability through withdrawing attention from postural control by concurrent cognitive task (i.e. dual-task condition) has been reported previously, but the effect of apathy, as a confounding factor, remains unknown. This study aimed to examine the effects of apathy and dual-task condition on postural control of chronic stroke survivors from biomechanical and neurophysiological perspectives. Twenty non-apathetic stroke survivors, 20 apathetic stroke survivors, and 20 sex-, age-, weight-, and height-matched healthy subjects were assessed using different postural sway measures and electromyography activity of ankle and hip muscles while quietly standing on rigid and foam surfaces under single-task, easy dual-task, and difficult dual-task conditions. The results showed postural instability and neuromuscular stiffening of stroke survivors, particularly apathetic stroke survivors, compared with healthy controls as evidenced by significantly greater postural sway measures and increased co-contraction of ankle muscles as well as hip muscles. Notably, concurrently performing a cognitive task significantly reduced postural instability and neuromuscular stiffening in chronic stroke survivors even in those with apathy. In conclusion, apathy exacerbates postural control impairments in chronic stroke survivors promoting an inefficient conscious mode of postural control. It is recommended that distracting the attention away from postural control by performing a concurrent cognitive task can be considered an effective strategy while designing interventions for improving postural control in apathetic stroke survivors.

Psychometric properties of dexterity questionnaire-24 in Iranian chronic stroke survivors.

INTRODUCTION: Dexterity is one of the most critical upper extremity functions that may be impaired in chronic stroke survivors. This study aimed to investigate the psychometric properties of DextQ-24 in Iranian chronic stroke survivors. METHOD: A total of 123 people with chronic stroke were included in the study. Internal consistency and test-retest reliability were assessed through Cronbach's alpha and Interclass Correlation (ICC), respectively. Dimensionality was performed by Exploratory Factor Analysis. In addition, to assess the convergent validity of DextQ-24, Box and Block Test, Motor Activity Log Questionnaire, ABILHAND Questionnaire, and Purdue Pegboard Test were used. Discriminant validity of DextQ-24 was measured between different stages of recovery (Brunnstrom stage). Acceptability was calculated by ceiling and floor effect. RESULTS: Cronbach's alpha and ICC were 0.92 and 0.91, respectively. The 24 items of this questionnaire were classified into six components. Further, a moderate to strong correlation between the total score of DextQ-24 with other tools | r = 0.41-0.84 | was obtained. The results of discriminant validity approved the ability of the total score of DextQ-24 to separate different stages of recovery. The results also reported that this questionnaire did not have a significant ceiling and floor effect. CONCLUSION: The results of our study showed that the Persian DextQ-24 has high reliability and a good convergent and discriminant validity in people with chronic stroke for dexterity measurement as a PROM questionnaire.

Barthel Index and modified Rankin Scale: Psychometric properties during medication phases in idiopathic Parkinson disease.

BACKGROUND: Independence in activities of daily living (ADL) is one of the most important aspects in planning treatment for people with Parkinson disease (PD). The Barthel Index (BI) and modified Rankin Scale (mRS) are commonly used in neurological diseases. OBJECTIVE: This study was conducted to confirm the validity and reliability of the BI and mRS in PD during ON and OFF medication phases. METHODS: We included 260 individuals with a diagnosis of idiopathic PD. The disability in ADL was measured by the BI, mRS, Parkinson's Disease Questionnaire-39 (PDQ-39), Unified Parkinson Disease Rating Scale-Activities of Daily Living (UPDRS-ADL), and Schwab and England ADL scale (SE). Test-retest, inter-rater reliability, and internal consistency were assessed by the intra-class correlation (ICC) and Cronbach α coefficients. Dimensionality was evaluated by factor analysis. Convergent validity was assessed by the SE, Berg Balance Scale (BBS), PDQ-39 and UPDRS-ADL. RESULTS: For the 260 participants (187 [71.9%] males; mean [SD] age 60.3 [12.3] years), both the BI and mRS achieved an acceptable level of test-retest and inter-rater reliability (ICC=0.77 to 0.91) in ON and OFF medication phases. The Cronbach α for BI was 0.85 and 0.88, respectively. We found 1 and 2 factors for BI in ON and OFF phases, respectively. Investigation of convergent validity showed moderate to high correlation for the BI with the UPDRS-ADL, SE, PDQ-39 (ADL), BBS and mRS scores in ON and OFF phases (ρ=0.51-0.74) and mRS with SE, UPDRS-ADL, PDQ-39 (ADL) and BBS scores (ρ=0.48-0.82). CONCLUSION: The BI and mRS showed acceptable validity and reliability to measure the degree of disability in patients with PD in daily activities in both ON and OFF medication phases.

Can Postural Instability in Individuals with Distal Radius Fractures Be Alleviated by Concurrent Cognitive Tasks?

BACKGROUND: Although impaired postural control may be a risk factor for distal radius fractures (wrist fractures), which often are caused by falls, little attention has been given thus far to the various performance and neurophysiologic aspects involved. Although studies suggest that external focus and cognitive tasks can improve postural control, it remains unclear whether these benefits are observed in individuals with a history of distal radius fracture and to what extent. QUESTIONS/PURPOSES: (1) To compare patients with a history of distal radius fracture to age- and sex-matched controls in terms of postural stability while standing on stable and unstable support surfaces, using both postural sway and neurophysiological measures as endpoints; and (2) to determine whether internal- and external-focus strategies and cognitive tasks can improve postural stability in these patients. METHODS: Forty patients with distal radius fracture (33 females and seven males with a mean ± SD age of 56 ± 4 years) and 40 sex- and age-matched control participants participated in the study. We recruited patients with a history of fall-induced distal radius fractures occurring between 6 and 24 months before the start of our study. We excluded patients who had any of the following: fear of falling, taking any medication that may affect balance, neurologic disorders, dizziness, vestibular problems, Type II diabetes, musculoskeletal disorders or recent history of lower extremity fracture, any recent surgical interventions in the spine or lower limbs, and/or cognitive impairment. Of 120 patients who were being treated for distal radius fracture over the 18-month period, 91 (76%) agreed to participate and 40 eligible patients were finally enrolled. The control group included sex- and age-matched (within 2-year intervals) individuals who had never had a wrist fracture. This group was selected from attendants/relatives of the patients attending the neurology and physical medicine and rehabilitation outpatient departments, as well as other volunteers with no history of balance problems or wrist fractures. To address our primary research question, we compared the postural control of individuals with a history of distal radius fracture with the control group while quietly standing on different support surfaces (rigid and foam surfaces) using both postural sway measures obtained by a force plate as well as neurophysiological measures (electromyography [EMG] activity of tibialis anterior and medial gastrocnemius). To address our secondary research question, we compared the postural sway measures and EMG activity of the ankle muscles between different experimental conditions (baseline, internal focus (mentally focusing on their feet without looking), external focus (mentally focusing on rectangular papers, placed on the force plate or foam, one under each foot), difficult cognitive task (recalling maximum backward digits plus one) and easy cognitive task (recalling half of the maximum backward digits). RESULTS: Patients with distal radius fractures presented with greater postural sway (postural instability) and enhanced ankle muscle activity compared with their control counterparts, but only while standing on a foam surface (mean velocity: 5.4 ± 0.8 versus 4.80 ± 0.5 [mean difference = 0.59, 95% CI of difference, 0.44-0.73; p < 0.001]; EMG root mean square of the tibialis anterior: 52.2 ± 9.4 versus 39.30 ± 6 [mean difference = 12.9, 95% CI of difference, 11.4-14.5; p < 0.001]). Furthermore, a decrease in postural sway was observed while standing on both rigid and foam surfaces during the external focus, easy cognitive, and difficult cognitive conditions compared with the baseline (for example, mean velocity in the baseline condition compared with external focus, easy cognitive task and difficult cognitive task was: 4.9 ± 1.1 vs 4.7 ± 1 [mean difference = 0.14, 95% CI of difference, 0.11-0.17; p < 0.001], 4.6 ± 1 [mean difference = 0.25, 95% CI of difference, 0.21-0.29; p < 0.001], and 4.5 ± 1 [mean difference = 0.34, 95% CI of difference, 0.29-0.40; p < 0.001] in the wrist fracture group). The same result was obtained for muscle activity while standing on foam (EMG root mean square of tibialis anterior in the baseline condition compared with external focus, easy cognitive task and difficult cognitive task: 58.8 ± 7.2 versus 52.3 ± 6.6 [mean difference = 6.5, 95% CI of difference, 5.5-7.6; p < 0.001], 48.8 ± 7.1 [mean difference = 10.1, 95% CI of difference, 9-11.1; p < 0.001], 42.2 ± 5.3 [mean difference = 16.7 95% CI of difference, 15.1-18.2; p < 0.001] in the wrist fracture group). CONCLUSIONS: The current results suggest that patients with a history of distal radius fractures have postural instability while standing on unstable support surfaces. This instability, which is associated with enhanced ankle muscle activity, conceivably signifying an inefficient cautious mode of postural control, is alleviated by external attention demands and concurrent cognitive tasks. CLINICAL RELEVANCE: The findings of this study may serve as a basis for designing informed patient-specific balance rehabilitation programs and strategies to improve stability and minimize falls in patients with distal radius fractures. The integrative methodology presented in this work can be extended to postural control and balance assessment for various orthopaedic/neurological conditions.

Time-course investigation of postural sway variability: Does anxiety exacerbate the sensory reweighting impairment in chronic stroke survivors?

Although anxiety is one of the most prevalent psychological disorders in stroke survivors, its effect on sensory reweighting has not yet been fully studied. The aim of this work was to investigate how anticipation of collision avoidance events affects sensory reweighting in chronic stroke survivors with low and high levels of anxiety (LA-stroke and HA-stroke, respectively), as compared with healthy controls (HC), under the condition of perturbed proprioception. Eighteen LA-stroke and 18 HA-stroke survivors, as well as 18 gender- and age-matched HC, participated in this study. Postural sway variability (i.e. Root Mean Square (RMS) of the COP velocity) was measured for a duration of 180 s under two conditions: quiet standing and standing while predicting random virtual spheres to be avoided. Proprioceptive perturbation was simulated using bilateral Achilles tendon vibration at mid duration (60 s) for both conditions. The results showed that the HC were able to timely use visual anticipation to reduce the postural sway variability induced by tendon vibration. However, marked delay in using such anticipation was observed in stroke participants, especially in the HA-stroke group, as indicated by a significant decrease in the RMS of the COP velocity late in the vibration phase. This is the first study to consider the effect of anxiety while comparing sensory reweighting between stroke and healthy participants. The results indicated that chronic stroke survivors, particularly those with HA, could not efficiently use sensory reweighting to maintain balance in sensory conflicting conditions, which may subject them to loosing balance and/or falling. These findings are critical for future assessment and planning of rehabilitation interventions and balance in chronic stroke survivors.