Examination of the traction effect in an artificial muscle-type dynamic traction orthosis using computed tomography.

BACKGROUND: Dart-throwing motion from radial dorsiflexion to palmar flexion has recently attracted attention as a functional movement direction of the wrist joint. We developed a novel artificial muscle-type dynamic traction orthosis (DTSaM) that includes these movements. This prospective crossover controlled study aimed to compare the traction effects in the presence and absence of DTSaM using computed tomography. METHODS: Healthy participants with no history of finger disease (6 men: 6 fingers, 4 women: 4 fingers; average age [range]: 29.4 [34-24] years) were examined. The distance and area of the joint space between the radiolunate (RL) and capitolunate (CL) joints were evaluated using 2 types of computed tomography: automatic movement and DTSaM. RESULTS: Participants with DTSaM showed more dilated joint space distance on the dorsal and central sides ( p < 0.05) and larger joint space areas on the dorsal side ( p < 0.05) of the RL and CL joints than those without orthosis. Significant differences in the magnitude of change in each joint were observed between the RL and CL joints regarding the joint space distance on the dorsal ( p = 0.021) and central ( p = 0.038) sides and the joint space area on the dorsal side ( p = 0.044). CONCLUSIONS: The movement of the CL joint is important in the dorsiflexion direction. Our results suggest that the dilated CL joint allows dorsiflexion and that combined traction and dart-throwing motion exercises may be possible for wrist joint contracture.

Analysis of a New Artificial Muscle Type Dynamic Orthosis for Wrist Joint Disease Using a Three-dimensional Motion Analyzer.

OBJECTIVES: Recently, the dart-throwing motion (DTM) has attracted attention as a functional direction of wrist joint motion. Consequently, we devised a new artificial muscle-type dynamic orthosis (Dynamic Traction Splint by Artificial Muscle, DTSaM) to reproduce DTM. This study analyzed the automatic motion of the wrist joint using a three-dimensional motion analysis system to assess how closely the DTSaM replicates DTM. METHODS: The DTSaM orthosis incorporates two McKibben-type rubber artificial muscles, and measurements were performed using image analysis software and a three-dimensional motion analysis system. The wrist radial angle (WRA) was defined as the angle between the line connecting the head of the index finger metacarpal to the radial styloid process and the line connecting the radial styloid process to the lateral epicondyle of the humerus. WRAs were investigated from 60° of palmar flexion to 60° of dorsiflexion. RESULTS: For dorsiflexion, comparisons of radial deviation and wrist ulnar angle (WUA) between the motion obtained using the DTSaM orthosis and active DTM showed a significant difference (P <0.05) at 30° and 60°, respectively. For palmar flexion, the same comparison showed a significant difference for both the ulnar and radial deviations (30°, P <0.05; and 60°, P <0.01, respectively). Furthermore, WUA showed a significant difference at 50° (P <0.05). Intraclass correlation coefficient analyses yielded good reliability with an average value of ≥0.8. CONCLUSION: The DTSaM orthosis produces a motion similar to the DTM. It is hoped that the use of the DTSaM orthosis will help to shorten the treatment period for patients with wrist disease.

Visuospatial working memory dysfunction from tapping span test as a diagnostic tool for patients with mild posterior cortical atrophy.

Posterior cortical atrophy is a rare degenerative condition with prominent visuospatial dysfunction which commonly occurs between ages 50 and 65. A diagnosis of mild posterior cortical atrophy sometimes challenging and can be delayed because there are currently no established neuropsychological examination methods that can easily be used in clinical settings. In this study, we examined whether the tapping span test is a potential diagnostic tool for posterior cortical atrophy and what impairment the tapping span test is indicative of in this condition. Eight patients with mild posterior cortical atrophy were recruited. Age- and severity-matched individuals with amnesic Alzheimer's disease (n = 9) were also recruited as a control group. The participants were subjected to the tapping span test and several visuospatial working memory tests. The results of the tapping span and visuospatial working memory tests were worse for the posterior cortical atrophy group when compared with the control group. The results from the tapping span tests were strongly correlated with those from the visuospatial working memory tests. The tapping span test is a simple and potentially useful diagnostic tool for patients with mild posterior cortical atrophy, as it reflects visuospatial working memory function.

Numeric input operation on electronic devices among individuals with visuospatial working memory impairment.

ABSTRACTIn human-computer interactions, higher-level visuospatial function is likely needed to effectively use the interface. The aim of this study is to clarify whether individuals with visuospatial defects can use electronic devices effectively. We quantitatively and qualitatively analyzed the ability of seven individuals with Bálint syndrome and seven individuals with left-unilateral spatial neglect (USN) to input a digit sequence into a flat touch interface. Control groups consisted of seven individuals with memory deficits and 11 healthy individuals. Participants with Bálint syndrome took longer and had more hesitations than the USN group and the two control groups to input numerical sequences (Steel-Dwass test, p < .01). In addition, participants with Bálint syndrome had a high percentage of hesitations for exploration of the button array on the interface relative to USN and the memory deficit group (Fisher's exact test, p < .05). Regarding neuropsychological data, participants with Bálint syndrome had a lower score for visuospatial working memory than participants with USN and the memory deficits control group (Steel-Dwass test, p < .01). The results shed some light on the relation between visuospatial working memory deficits and the spatial perception of interface layouts and spatial control during electronic device operation.

Effectiveness of Use of Button-Operated Electronic Devices Among Persons With Bálint Syndrome.

OBJECTIVE: Little is known about how visuospatial deficits affect the use of electronic devices operated by pressing spatially interspersed buttons. This study aimed to determine whether people with Bálint syndrome can effectively use such devices. METHOD: We quantified the ability of 7 study participants with Bálint syndrome to use button-operated electronic devices by measuring the time required to input digit sequences into three different types of devices. Control groups were 8 participants with amnesia and 8 healthy participants. RESULTS: Participants with Bálint syndrome took longer to input a digit sequence on all three devices than did those in the two control groups. Although we found no significant differences with respect to type of device, 2 of 3 participants with severe Bálint syndrome were able to input one- to five-digit sequences with the electronic calculator. CONCLUSION: Distinctive design features might positively affect the performance of people with Bálint syndrome.

Visuospatial working memory is severely impaired in Bálint syndrome patients.

Although it has been proposed that visuospatial working memory may be impaired in Bálint syndrome patients, neither a systematic study concerning this proposal nor a comparison with patients having right-parietal damage has been made. Visuospatial working memory was assessed for six Bálint syndrome patients and members of two control groups-one composed of individuals with right-parietal damage (n = 15) and a second of age- and gender-matched healthy individuals (n = 26). We placed special emphasis on patients with a mild form of Bálint syndrome who can judge positional relationships between two objects. First, the participants were subjected to delayed visuospatial matching tasks. Next, their visuospatial-temporal integration abilities were assessed using a shape-from-moving-dots task. Visuospatial working memory was impaired for Bálint syndrome patients compared with controls according to the results of the tests. The differences between the Bálint syndrome and control subjects remained when only data for patients with the mild form of Bálint syndrome were included. We conclude that visuospatial working memory may be severely impaired in Bálint syndrome patients and, therefore, might influence their inability to properly execute movements and behaviours associated with daily living.