Age-Related Differences in Strategy in the Hand Mental Rotation Task.

Mental imagery of movement is a potentially valuable rehabilitation task, but its therapeutic efficacy may depend on the specific cognitive strategy employed. Individuals use two main strategies to perform the hand mental rotation task (HMRT), which involves determining whether a visual image depicts a left or right hand. One is the motor imagery (MI) strategy, which involves mentally simulating one's own hand movements. In this case, task performance as measured by response time (RT) is subject to a medial-lateral effect wherein the RT is reduced when the fingertips are directed medially, presumably as the actual motion would be easier. The other strategy is to employ visual imagery (VI), which involves mentally rotating the picture and is not subject to this medial-lateral effect. The rehabilitative benefits of the HMRT are thought to depend on the MI strategy (mental practice), so it is essential to examine the effects of individual factors such as age, image perspective (e.g., palm or back of the hand), and innate ability (as indicated by baseline RT) on the strategy adopted. When presented with pictures of the palm, all subjects in the current study used the MI strategy, regardless of age and ability. In contrast, when subjects were presented with pictures of the back of the hand, the VI strategy predominated among the young age group regardless of performance, while the strategy used by middle-age and elderly groups depended on performance ability. In the middle-age and elderly groups, the VI approach predominated in those with high performance skill, whereas the MI strategy predominated among those with low performance skill. Thus, higher-skill middle-aged and elderly individuals may not necessarily form a motion image during the HMRT, potentially limiting rehabilitation efficacy.

Variation in Performance Strategies of a Hand Mental Rotation Task on Elderly.

A hand mental rotation task (HMRT) is a task wherein a person judges whether an image of a rotated hand is of the right or left hand. Two performance strategies are expected to come into play when performing these tasks: a visual imagery (VI) strategy, in which an image is mentally rotated, and a motor imagery (MI) strategy, in which the movement of a person's own hand is simulated. Although elderly people generally take some time to perform these tasks, ability differs greatly between individuals. The present study hypothesizes that there is a relationship between differences in task performance strategy and performance ability, and it compares performance strategy among elderly people divided into groups with a short mental rotation time and a long mental rotation time. In response to images of the palm, both groups displayed a medial-lateral effect in which responses were faster for images where the third finger was rotated toward the midline of the body than images rotated in the opposite direction, and we inferred that an MI strategy was primarily employed. Meanwhile, in response to images of the back of the hand, a medial-lateral effect was also observed in the group with a long mental rotation time and not in the group with the shortest mental rotation time (VI strategy). These results suggest that different strategies for performing HMRT task are used by elderly people with a short mental rotation time and those with a long mental rotation time.

Evaluation of Activities of Daily Living/Instrumental Activities of Daily Living to Accurately Determine Severity of Moderate and Severe Alzheimer's Disease: Comparison of Assessments by Receiver Operating Characteristic Curve and Discriminant Analyses.

AIM: The aim of this study was to determine Activities of Daily Living/Instrumental Activities of Daily Living (ADL/IADL) evaluations that will enable better understanding of the severity of Alzheimer's disease (AD). METHODS: AD patients were evaluated by Functional Independence Measure (FIM), Hyogo Activities of Daily Living Scale (HADLS), and Assessment of Motor and Process Skills (AMPS) to identify the assessments that will enable highly precise discrimination of AD Clinical Dementia Rating (CDR) 2 (moderate) and CDR3 (severe) using receiver operating characteristic (ROC) curve and discriminant analyses. RESULTS: The participants were 75 AD patients (CDR2 = 50, mean age = 80.3 ± 5.9 years; CDR3 = 25, mean age = 78.3 ± 9.0 years). The evaluation methods consisted of FIM, HADLS, and AMPS. The results were divided into FIM-M, FIM-C, HADLS-ADL, HADLS-IADL, AMPS-motor skills, and AMPS-process skills. The values for the area under the curve (AUC) were compared by ROC curve and discriminant analyses. AUC values for FIM-C and AMPS-process skills were 0.956 and 0.947, respectively. With these two evaluations only, values ≥0.9 were shown. Moreover, the AUC of the discrimination score (combination of the FIM-C and AMPS-process skills) was significantly higher than those for FIM-M, FIM-C, HADLS-ADL, HADLS-IADL, and AMPS-motor skills. CONCLUSIONS: The results demonstrated that evaluation by FIM-C and AMPS-process skills methods was useful for discriminating between CDR2 (moderate) and CDR3 (severe) AD. Moreover, the results indicated that these two evaluation methods enabled more accurate determination of severity and the spared capabilities of AD patients.

Response time differences between men and women during hand mental rotation.

This study explored gender differences in correct response rates and response times on a task involving left or right arrow selection and another involving the transformation of mental rotation of the hand. We recruited 15 healthy, right-handed men (age 24.5 ± 6.4) and 15 healthy, right-handed women (age 21.3 ± 4.9). For the tasks, we used pictures of left and right arrows and 32 hand pictures (left and right, palm and back) placed in cons (each at 45° from 0° to 315°). Hand and arrow pictures alternated and were shown at random. Participants decided as quickly as possible whether each picture was left or right. To compare the time taken for the transformation of mental rotation of the hand, we subtracted the average arrow response time from that for the left and right hand pictures for each participant. Correct response rates did not differ significantly between men and women or left and right for either arrow or hand pictures. Regardless of gender, the response time was longer for the left arrow picture than right arrow picture. The response time for the hand picture was longest for both men and women for pictures at rotation angles that were most difficult to align with participants' hands. While there was no difference between men's responses for left and right hand pictures, the responses of women were longer for left than right hand pictures and also than those of men. These findings suggest that both men and women mainly perform the hand mental rotation task with implicit motor imagery. On the other hand, the gender difference in performance might be explained by the difference in balance with other strategies, such as visual imagery, and by cognitive, neurophysiological, and morphological differences.

Effects on activities of daily living and instrumental activities of daily living independence in patients with Alzheimer's disease when the main nursing caregiver consciously provides only minimal nursing care.

[Purpose] We investigated whether the activities of daily living and instrumental activities of daily living independence in patients with Alzheimer's disease are positively affected by the main nursing caregiver consciously aiming to provide only minimal nursing care. [Participants and Methods] The participants comprised 105 patients (men: 46, women: 59, mean age: 80.1 ± 6.7 years). We conducted interviews to establish whether the main nursing caregivers consciously aimed to provide only minimal nursing care (care consciousness), and participants were thus divided into two groups. Hyogo Activities of Daily Living Scale scores of the groups with and without care consciousness were compared by dementia severity. [Results] In patients with mild Alzheimer's disease, activities of daily living and instrumental activities of daily living independence in the group with care consciousness were significantly higher than in the group without care consciousness. In patients with moderate Alzheimer's disease, instrumental activities of daily living independence was significantly higher in the group with care consciousness than in the group without care consciousness. [Conclusion] Thus, positive effects on the activities of daily living and instrumental activities of daily living independence are observed when the main nursing caregivers consciously aim to provide only minimal nursing care to patients with Alzheimer's disease.

Quantitative and Qualitative Analyses of the Clock Drawing Test in Fall and Non-Fall Patients with Alzheimer's Disease.

AIM: The clock drawing test (CDT) is widely used as a visual spatial ability test and screening test for dementia patients. The appearance frequency of qualitative errors obtained through the qualitative analysis of CDT may be related to the participant's falls. The aim of this study was to clarify the difference in the number of people who presented with qualitative errors in the CDT between a fall and non-fall group of patients with Alzheimer's disease (AD). METHODS: The CDT was implemented for 47 patients with AD. A quantitative analysis was conducted, and a qualitative analysis was performed for errors. The patients were divided into two groups based on their history of falls over the past year. The results of the CDT quantitative analysis were tested using the Mann-Whitney U test, and Fisher's exact test was employed to determine the difference in the number of people who presented with error types between the two groups (fall group, non-fall group) in the CDT qualitative analysis. RESULTS: In the quantitative analysis, a significant difference was found for the total scores, with the total CDT score of the fall group (n = 22) significantly lower than that of the non-fall group (n = 25) (p = 0.006, effect size: φ = 0.40). In the qualitative analysis, a significantly higher number of patients in the fall group than in the non-fall group presented with a conceptual deficit (p =0.001, φ = 0.51). No differences were found in the number of patients in the two groups who presented with the other five error types. CONCLUSIONS: These results showed that a lower score in the CDT quantitative analysis might suggest an increased risk of falls. It was also clarified that a larger number of patients in the fall group than in the non-fall group presented with a conceptual deficit of the qualitative error types in the CDT. Therefore, these results suggest that the appearance of a conceptual deficit may be an index for the selection of patients with AD prone to falling when implementing fall prevention measures.

Reaction time differences between left- and right-handers during mental rotation of hand pictures.

During mental rotation tasks using hand pictures, right-handers make left-right judgements by mentally rotating their own hand to an orientation of the presented hand image. Although strategy difference for the tasks between left- and right-handers has been suggested, the strategy of left-handers has been incompletely understood. In the present study we compared differences in reaction times between 15 left-handed and 16 right-handed normal individuals during a mental rotation task using simple hand pictures. Participants were required to identify pictures of a hand presented in four orientations (upright, counterclockwise rotated, clockwise rotated, and inverted) as either a right or a left hand. Right-handers recognised a right hand faster than a left hand, whereas no significant difference was seen for left-handers. Both left- and right-handers recognised a right hand faster than a left hand in counterclockwise-rotated images, and recognised a left hand faster than a right hand in clockwise-rotated images. The findings suggest that the differences in the reaction times between left- and right-handers depend on a laterality balance of hand motor skills. During mental rotation task using simple hand pictures, left-handers may mentally simulate their own hand to match the stimulus image as similar to right-handers.

Cerebral laterality differences in handedness: a mental rotation study with NIRS.

Spatial cognition is right-hemisphere dominant in right-handers, but hemispheric laterality in left-handers is not fully understood. Using near-infrared spectroscopy, we compared cerebral activations in the frontal and parietal lobes during a mental rotation task between seven healthy right-handed and seven healthy left-handed women. Cerebral laterality during the spatial cognition task was evaluated as balance in the extent of activation areas between the two cerebral hemispheres, using the right-hemispheric dominance index (RI). RIs of right-handers showed right-hemispheric dominance (RI>0) in both frontal (RI=0.31+/-0.25) and parietal (RI=0.28+/-0.37) lobes, while left-handers showed slight left-hemispheric dominance (RI<0) in both frontal (RI=-0.13+/-0.18) and parietal (RI=-0.22+/-0.22) lobes. The left-handers exhibited significantly larger amplitudes of activation at the channels overlying the left-superior parietal lobule, whereas the right-handers did not show such amplitude differences. These findings suggest a difference in cerebral hemispheric laterality for spatial cognition between left- and right-handers.

Shift of motor activation areas during recovery from hemiparesis after cerebral infarction: a longitudinal study with near-infrared spectroscopy.

Motor functional recovery after stroke may be attributable to cerebral reorganization. We used near-infrared spectroscopy, which measures non-invasively the changes in oxy- and deoxy-hemoglobin concentrations in response to neural activation, for monitoring cerebral activation in stroke patients, and investigated the longitudinal changes in functional laterality of activations in the primary sensorimotor cortex during unilateral audio-paced (1 Hz) hand movement. We examined five ischemic stroke patients (4 females and 1 male, 52-67 years old) with mild to moderate hemiparesis at acute stages and chronic stages at least 1 month later. Normal subjects (3 females and 2 males, 47-63 years old) were also included. Unilateral hand movement activated predominantly the contralateral primary sensorimotor cortex in the normal subjects and the stroke patients when they moved unaffected hand. Affected hand movements activated bilateral sensorimotor cortices early after stroke (< 25 days of stroke onset), whereas the activation pattern returned toward normal at later periods (> 35 days). The contralaterality index (0.34 +/- 0.12 in normal control) was reduced at early periods (0.00 +/- 0.03, p < 0.01) after stroke, and returned to normal (0.35 +/- 0.24) as motor function recovered. These findings suggest that a transient increase in motor activation in the ipsilateral intact hemisphere within 1 month may play an important role in the recovery from motor dysfunction after stroke.