Differential Effects of the Interaction Between the Education and APOE ε4 Allele on Amyloid-beta Retention and Memory Performances in Cognitively Normal Older Adults and Alzheimer's Disease Patients.

BACKGROUND: Despite the effect of education and APOE ε4 allele on amyloid-beta (Aß) retention and memory, previous studies have not dealt with an interaction between two factors on Aß deposition and memory function in the course of Alzheimer's disease (AD). OBJECTIVE: To evaluate education by APOE ε4 allele interactions for Aß retention and neuropsychological test scores in cognitively normal older adults without Aß deposition [CN(Aß-), n=45] and Alzheimer's disease patients with Aß retention [AD(Aß+), n=33]. METHODS: Multiple regression analyses (adjusted for age, gender) were conducted to examine the effects of education, APOE ε4 allele, and the interaction between the two factors on global, regional Aß load quantified using [18F]flutemetamol standardized uptake value ratio with the pons as a reference region, and on neuropsychological test scores in each group. RESULTS: The interaction between education and APOE ε4 allele had an effect on amyloid load in parietal lobes (uncorrected p<0.05) and striatum (Bonferroni corrected p<0.05) in each CN(Aß-) and AD(Aß+). There was also an interaction effect of education and APOE ε4 allele on the memory performance in each CN(Aß-) and AD(Aß+) (uncorrected p<0.05). APOE ε4 carriers of both groups showed opposing slopes with each other in the correlation between the education years and Aß load, memory performance. CONCLUSION: The current results suggest a possible explanation of the differential effects of education and APOE ε4 allele interactions on AD pathology and memory function at the beginning and end of AD progress. However, further study with a validating cohort is needed for confirming this explanation.

Shoulder dysfunction assessment: self-report and impaired scapular movements.

BACKGROUND AND PURPOSE: Shoulder dysfunction is common in various patient populations. This investigation was performed to assess shoulder dysfunction with self-report and performance-based functional measures. SUBJECTS: Fifty men (25 with shoulder dysfunction and 25 without shoulder dysfunction) participated in this study. METHODS: Self-report functional disabilities were assessed with the Flexilevel Scale of Shoulder Function (FLEX-SF), and electromagnetic tracking sensors were used to monitor 3-dimensional scapular movements during 4 functional tasks. RESULTS: Relative to the control group, the group with shoulder dysfunction showed significant alterations in scapular movements (averages of 6.9 degrees less posterior tipping, 5.7 degrees less upward rotation, and 2.3 cm more elevation). Scapular kinematics correlated significantly (r) with the Self-report FLEX-SF measure during functional tasks (posterior tipping = .454 to .712, upward rotation = .296 and .317, and elevation = -.310). DISCUSSION AND CONCLUSION: Functional disabilities were identified with self-report and performance-based functional measures. The inadequate scapular posterior tipping and scapular upward rotation as well as the excessive elevation may have implications in planning intervention strategies for people with shoulder dysfunction.

Effect of shoulder tightness on glenohumeral translation, scapular kinematics, and scapulohumeral rhythm in subjects with stiff shoulders.

Shoulder tightness may cause altered kinematics and lead to development of subacromial impingement, tendinitis, and degenerative changes. In this investigation, the humeral head translations, scapular kinematics, and scapulohumeral rhythm were determined with a three-dimensional electromagnetic tracking device during arm elevations in six subjects with anterior shoulder tightness and in six subjects with posterior shoulder tightness to study the effects of anterior/posterior tightness on shoulder kinematics. Subjects with anterior tightness showed lower slopes in curves of glenohumeral elevation plotted against scapular upward rotation (scapulohumeral rhythm, 0.11 to 0.32; p = 0.021) and less posterior scapular tilt (2.9 to 7.5 degrees; p = 0.002) during arm elevations when compared to the group with posterior tightness. The humeral head was positioned less posteriorly (2.2 to 3.4 mm; p = 0.004) and more superiorly (3.8 to 7.0 mm; p < 0.0005) during arm elevation in subjects with posterior tightness. The alternations in shoulder kinematics between subjects with anterior and posterior shoulder tightness may be relevant to the development of subacromial impingement, tendinitis, and degenerative changes as seen in subjects with stiff shoulders.

Altered patterns of muscle activation during performance of four functional tasks in patients with shoulder disorders: interpretation from voluntary response index.

Altered motor control of the shoulder muscles during performance of a specific motor task in patients with shoulder disorders (SDs) has been an interesting subject to researchers. This study compared shoulder muscle activation patterns by surface electromyography (sEMG), including the upper trapezius (UT), lower trapezius (LT), and serratus anterior (SA) muscles, during four functional tasks in 25 patients with SDs and controls. A voluntary response index (VRI) was calculated, including magnitude and similarity index (SI), to quantify sEMG patterns during four functional tasks. Responsiveness and clinically meaningful levels of discrimination between patients and control for EMG magnitude and SI were determined. An altered pattern of motor control during four functional tasks was evident in the patients, in which greater EMG amplitude and abnormal EMG patterns were found. For SI among four functional tasks, normal subjects ranged from 0.80 to 1.00 while patients ranged from 0.70 to 0.99. High probabilities (97%) of discrimination between patients and normal subjects were found by SI method during an overhead height task (patients: 0.85-0.96, normal subjects: 0.95-1.00). Our results also suggest that an individual can be estimated to be abnormal when lower SI values are observed during the four functional tasks.

Functional activity characteristics of individuals with shoulder dysfunctions.

Shoulder-related dysfunction affects individuals' ability to function independently and thus decreases quality of life. Functional task assessment is a key concern for a clinician in diagnostic assessment, outcome measurement, and planning of treatment programs. The purpose of this study was to test the reliability of the FASTRAK 3-dimensional (3-D) motion analysis and surface electromyography (sEMG) systems to analyze 3-D shoulder complex movements during functional tasks and compare motion patterns between subjects with and without shoulder dysfunctions (SDs).For the test, sEMG and 3-D motion analysis systems were used to characterize the functional tasks. Twenty-five asymptomatic male subjects and 21 male subjects with right shoulder disorders performed four functional tasks which involved arm reaching and raising activities with their dominant arms. Reliability was estimated by the intraclass correlation coefficient (ICC). Motion pattern was compared between two groups using mixed analysis of variances (ANOVAs). Shoulder complex kinematics and associated muscular activities during functional tasks were reliably quantified (ICC=0.83-0.99) from the means of three trials. Relative to the group without SDs, the group with SDs showed significant alteration in shoulder complex kinematics (3 degrees -40 degrees ) and associated muscular activities (3-10% maximum). Scapular tipping, scapular elevation, upper trapezius muscle function, and serratus anterior muscle function may have implications in the rehabilitation of patients with SDs.

Functional activities characteristics of shoulder complex movements: Exploration with a 3-D electromagnetic measurement system.

The high prevalence of shoulder-related dysfunction has focused increased attention on functional activity assessment. This study (1) tested the reliability of three-dimensional shoulder complex movements during four functional tasks representing different levels of task difficulty, (2) characterized the four functional tasks, and (3) examined the relationships between age and shoulder movements. Twenty-five asymptomatic subjects, all veterans aged 30-82, performed the four functional tasks. Good within-session reliability was found (movement pattern: similarity index = 0.81 to 0.97, peak values: intraclass correlation coefficients = 0.88 to 0.99). The raising arm to overhead height task (hard task) placed the greatest demand on scapular motions and humeral elevation (p < 0.005). During the functional tasks, significant correlations existed between age and scapular tipping, humeral elevation, and scapular upward rotation (r = -0.62 to 0.50, p < 0.05). Correlation results indicated that elderly subjects have a greater potential for serratus anterior muscle weakness and shoulder capsule tightness.