Friday, 28 October 2011

Children throwing bean bags at targets

Yesterday I spent a couple of hours in the Biomechanics lab here at the Centre for Sport & Exercise Sciences. The lab is fully instrumented, with 10 cameras mounted 360° around the room integrated with a force plate built into the floor. This arrangement allows us to place passive markers (small pieces of reflective plastic) on a person and track these within quite a large volume of space; if one camera loses sight of the marker, one of the others can typically see it. The data from the cameras and force platform come out with a common time stamp, so you can line the data up and see what was happening when.

The reason I was in the lab was to try out a bright idea I've had with a colleague from Leeds Metropolitan for a study. One of the tasks I use to study perception and action is throwing over long distances to hit a target. I ask people to throw overarm to hit a 4ft x 4ft Perspex target from up to 15m away, and we record their throw with high speed cameras to measure the release angle and velocity of the ball. I'm also interested in the development of throwing; this is a very human skill, with all kinds of interesting psychological properties. It's considered a key motor skill for young children to acquire, so much so that it is one of the tasks measured in the Movement Assessment Battery for Children (Movement-ABC). This battery is commonly used to identify children with motor difficulties such as developmental coordination disorder, and throwing is one of the assessment tasks.

Perceptual Learning Immediately Yields New Stable Motor Coordination

The reason 0° is easy while other relative phases are hard is that the requisite information is detected most readily at 0°. This test predicts that if a participant were to improve their ability to detect the requisite information then their movement stability would improve.

There were 12 participants. Half the participants were assigned to the Experimental Group and half to the Control. There were two types of experimental task: two alternative forced choice (2AFC) judgements, and coordinated rhythmic movement. There were then two types of session:

1. Assessment sessions consisted of both judgement trials (at both 90° and 180°) and movement trials (moving at 0°, 90°, and 180°). There was no feedback.

2. Training consisted only of judgement trials at 90° with feedback.

The Experimental group did three assessment sessions and up to 14 training sessions. The Control group did three sessions of movement trials, with no training or feedback.
Judgements (Perceptual Ability)
Participants had to identify a target phase of 90° in a pair of displays. Participants then trained with progressively harder perceptual discriminations around 90° with feedback.
Movement Stability (Baseline, Post Training and Retention)
Participants used a joystick to coordinate the movement of two dots on a screen at three relative phases. Participants were instructed to move so as to produce a mean relative phase of 0°, 180°, or 90°, three trials of each.
A repeated measures ANOVA was used to check the significance between the two groups. Significant differences were found in the experimental group which shows that perceptual training was successful. The movement task found that only participants in the Experimental group improved their movement stability across sessions and this improvement was restricted to 90°.
To conclude participants in this experiment improved their movement stability at 90° following training to improve their perceptual ability at 90°. Also improved perceptual discrimination of 90° led to improved performance in the movement task at 90° with no training. The improvement persisted until Retention without further exposure to either task.

Monday, 24 October 2011

The learning of 90° continuous relative phase with and without Lissajous feedback: External and internally generated bimanual coordination

The primary aim of this experiment was to find out if reducing the amount of lissajous feedback would allow participants to develop an internal representation of the coordinated pattern, enabling them to effectively perform bimanual coordination tasks without any feedback.

Participants were randomly assigned to one of nine groups that differed in terms of the percent of time they received Lissajous feedback (100%, 50% or 0%). For the 50% feedback group Lissajous feedback was presented in a fading schedule (25–25–20–20– 15–15–10–10–5–5 s) for each consecutive trial. The feedback was provided at the beginning of each trial and withdrawn according to the schedule above.

Apriori comparisons indicated that after 5 minutes of practice, participants who received 50% feedback had considerably higher RMSE values on the no-Lissajous test compared with participants who received 100% feedback, t(12)=4.63, pb.05, on the Lissajous test. After 20 minutes of practice, participants who received 50% feedback performed just as well as the group who had received 100% feedback in a test with no Lissajous feedback.

More practice while receiving 100% Lissajous feedback did not help participants to develop an internal representation of the task or improve their ability to perform when the Lissajous feedback was present. On practice trials while receiving 50% Lissajous feedback participants seek out and process other sources of information necessary to perform the task. This could result in participants acquiring the capability to detect and correct errors. The result is improved performance on tests without extrinsic feedback.

Thursday, 20 October 2011

The ‘Timed Get-Up-And-Go’ test revisited: Measurement of the component tasks. Wall, J. Bell, C. Campbell, S and Davis, J.

The aim of the study was to compare the different results between the ‘Timed Get-Up-And-Go’ (TGUG) test and the ‘Expanded Timed Get-Up-And-Go’ (ETGUG) test on 3 groups. The TGUG only measures the time of the movement as a whole whereas the ETGUG could measure the component tasks of the test.

3 groups of 10 subjects participated on the study. Group 1 classified as the young control group aged between 19 and 29 years with a mean age of 25.5. Group 2 were classified as the elderly control group who were aged 65 and over with a mean age score of 72.7 years. Group 3 were classified as the at risk elderly group who were aged over 65 and had a mean age of 75.8 years. All of these subjects were receiving physical therapy, had a history of falls in the past two years or had been treated for gait pathologies or balance disorders.

The subjects all had to complete the ‘Timed Get-Up-And-Go’ test first. This involved standing up from a chair (seat height 46cm) and walking 3 meters at a normal pace, turning around walking back and returning to the seated position. The second test they all completed was the ‘Expanded Timed Get-Up-And-Go’ test. This involved them walking 10 meters so that component tasks could be timed using a multimemory stopwatch. The stopwatch was pressed at the following events: a) standing upright b) as the subject passed the 2m mark c) as the subject passed the 8m mark d) as the subject passes the 8m mark returning and e) as the subject passed the 2m mark returning.

The results displayed no significant differences in the times from the TGUG between the young control group and elderly control group. The young control group’s mean time was 7.36s. The mean time for the elderly control group was 8.74s and the at risk elderly group had a mean time of 18.14s to complete the task. Similar results were found for the ETGUG test. The mean time for the young control group was 15.36s, the elderly control group was 19.095s and the at risk elderly group was 34.52s. A significant difference was found between the young and at risk group and the elderly and the at risk group for every component task of the test. Both control groups were found to be significantly faster at each stage than the at risk group.

All the young and elderly control participants completed the TGUG test in less than 10 seconds which is consistent with previous findings therefore showing they are freely independent in physical mobility. In both of the tests it was found the elderly group and the at risk elderly group had difficulty standing up from the chair. Therefore it has been suggested that only this measure could be used in future research to predict a patient’s risk of falling. Additional research is needed to determine correlations between the increased time for specific component tasks and a decreased functional mobility.

Learning to throw to max distances: Do changes in release angle and speed reflect affordances for throwing?

Adults skilled at long distance throwing, able to pick optimum weight for max. distance (Bingham et al, 1989), but replicated and results from a larger range of object sizes and weights recorded (Zhu et al, 2008). A very functional relation between size and weight was established.
Zhu et al. investigated whether people without good throwing skills could perceive the affordance for throwing and if they would learn to. They were unable to select optimal objects for throwing with any accuracy, but once learned to throw for distance; could then see the affordance.
Affordance property - optimal distance of throws determined by initial angle and speed.
Hypothesis - object size and weight might affect dynamics of hefting in similar ways and that this similarity would allow hefting to provide information about affordance.
Study was performed for perceptual learning of the affordance while learning to throw and to study concurrent changes in the kinematics of throwing.
48 objects varying in size (marble to waterpolo ball)
18 Indiana Uni students that could throw but not at a competitive sporting level.
Ps were scheduled for 3mnths throwing practice randomly divided into 3 groups using ANOVA on throwing data gathered from pre-test.
Results: Mean distances of throws each of 6 objects for each group, during each week of practice and after practice, plotted against objects.
(1) Distance of throws - Distance increased after practice for all groups.
(2) Release angle - Throwing practice didn't yield significant changes in release angle, however consistency of release angle did increase amongst participants.
(3) Release speed - Mean release speed increased by as much as 50%, however each group exhibited different patterns.
(4) Distance vs Release Angle/Release Speed - Release angle not significant for systematic changes in distance. Release speed was significantly correlated with distance of throws.
(5) Effect of object size and weight on throwing - Object size does affect reliability with which near optimum release angles were produced. Size had no effect on mean angles of release or significant effect on distance of throw.

Wednesday, 19 October 2011

Perception & Action Lab: Perceptual Learning Immediately Yields New Stable Motor Coordination

Perception & Action Lab: Perceptual Learning Immediately Yields New Stable Motor Coordination

The purpose of this study is to determine whether perceptual training can significantly improve an unstable movement, which in this case is 90º.

12 participants (22-54 years old), half of which were assigned to an experimental group and the other to a controlled group. The experimental group participated in training sessions as well as assessment sessions, receiving feedback at the training sessions. The controlled group did three sessions of movement trials, with no feedback or training given. Experimental group took part in up to 14 training sessions (depending on how quickly plateau state of improvement occurred) and three assessment sessions. Each training set became increasingly harder; participants had a maximum of four repetitions to successfully complete each set otherwise they’d progress automatically to promote forced learning. Training did not involve any extensive practise regarding the movement task itself so learning is solely perception based.

Judgement data was analysed first to see whether the experimental group learnt as a result of the extensive training; which was followed by analysis of the movement data. A repeated measures ANOVA test was conducted to find out whether there were significant results regarding the two groups. Significant results were found in the experimental group, showing a significant improvement during training as well as improvements in movement assessment, which indicates a high correlation between the two. The repeated measures ANOVA test showed no significant results in the movement task (without perceptual training) concerning the controlled group.

This study concludes that participants improved their movement stability at 90 º due to improvements in perceptual training at 90 º.

The timed “Up & Go”: A test of basic functional mobility for frail elderly persons

The objective of this study was to examine the clinical usefulness of the timed “Up & Go” as a short test of basic mobility skills in population of frail elderly adults. The test being administered is very quick and practical to complete and covers the basic bodily movement. Mathias et al proposed this test before however his test had problems with the scoring system. But in this test conducted by Podsiadlo & Richardson a new scoring system was implemented to make the test more reliable and valid.

The test consisted of sixty participants from the community to the geriatric day hospital. Twenty three of the sixty were male and thirty seven of the sixty were female. Ten active, healthy, normal volunteers over the age of seventy were also tested. The subjects varied widely in their ability to perform all of the mobility tasks. The test was performed on patients attending the day hospital over a two month period. Those who had stage four Parkinson’s disease and were medically unstable were excluded from the study.

The test required the participants to stand up from a regular arm chair walk a distance of 3m, turn, walk back to the chair and sit down again. The subject is allowed to begin the test when they are given their cue to go. The subjects wear their normal footwear and are allowed to use their walking aid to assist them with the task. The subjects walk through the test once and then at the next attempt are timed for the real thing.

The results show that the time scores varied between ten to twenty seconds in fifty seven participants. Three of the participants were unable to perform the test. One could not get out of the chair and the other two could not walk without assistance. Seven participants did not have the stamina levels to complete the test. The results of the study seem to support the hypothesis of the timed “Up & Go” score would correlate with the patients balance, gait speed and functional capacity.

The timed “Up & Go” test is a useful screening test or a descriptive test. It gives information about the patients balance, gait speed and functional ability. It places the patients into a functional category and indicates those requiring further assessment. The timed “Up & Go” can indicate a lack of improvement or even a deterioration of which the patient or health care provider may be unaware. The test is reliable both between raters and over time. The test is adequate for a fragile elderly person because it is a simple task to complete which does not require a massive amounts of exertion.

Learning a co-ordinated Rhythmic movement with task- appropriate co-ordination feedback

Learning a co-ordinated Rhythmic movement with task- appropriate co-ordination feedback
One of the main assumptions made before this experiment was conducted was that when learning to produce a novel movement, people are unable to do it without training. This is explained to be because people are poor at discriminating the perceptual information required to co-ordinate and control the movement, which means people require additional (augmented) feedback to learn the novel task.
· Kelso (1995) stated that people can produce two stable co-ordination patterns without training 0° and 180°. In order to perform other i.e. 90° that pattern has to be learned. #
· Behaviour is said to be organised to the order parameter relative
· 0° and 180° are attractors in this space and in order to learn a new novel co-ordination movement a new attractor has to be created
Perception – action perspective
· This proposes that the phenomena of learning a co – ordinated rhythmic movement emerges from a task dynamic that includes perceptual information as a crucial element (Bingham 2001)
· Learning to produce a novel and unknown movement requires augmented feedback so that the learner knows what they are doing right or wrong
· Visual metronomes and Lissajous figures are used as a way of obtaining feedback; however these methods transform the task so that it no longer is a co-ordination task.
· Both methods show that relative direction is not defined in the feedback display and this alters the process of acquiring a novel co-ordination
· The objective of the task was to describe and test a new method for providing online augmented co-ordination feedback using a neutral colour cue
· Ten participants were split into 2 groups of 5. Group 1 received co-ordination feedback during training, group 2 received no feedback but an equal exposure to the task
· The study concluded that a new method for providing the augmented feedback necessary for learning novel co-ordinated rhythmic movements was developed
· An advantage of this new method is that it doesn’t alter or remove the visual information about the co-ordination task which the other methods do.

Tuesday, 18 October 2011

Learning a coordinated rhythmic movement with task appropriate coordination feedback

The aim of the study was to find out whether feedback aided individuals ability to correctly coordinate a specific rhythmic movement task. This task involved participants doing a coordinated rhythmic movement at 90˚ mean relative phase. Previous studies have suggested that individuals are able to produce 0˚ and 180˚ movement patterns without training; however 90˚ is a lot more difficult without the aid of feedback or training. Therefore the study measured whether the participants were to successfully learn a novel task both with feedback and without feedback.
10 participants were split into two groups of five individuals. Both groups had the same amount of time to complete the training under two conditions: group 1 (“Feedback”), received feedback during training, whereas group 2 (“Control”) received no feedback during their training. Both groups initially received a baseline assessment session where they viewed a demonstration of the relative movement of 90˚ on a computer screen which they then had 20 seconds to repeat the viewed movement, five times. A computer controlled dot and a metronome was used as a reference point for the individual to produce their movement.
Five later sessions involved the participants receiving training either using feedback for the “Feedback” group or no feedback for the “Control” group. Feedback included the same procedure as the bassline session but participants now had a green coloured dot which indicated that the individual was creating a coordinated movement of 90˚± mean relative phase. As training sessions progressed the error bandwidth decreased from 40˚ then 30˚, 20˚, 15˚ and finally 10˚±, therefore whilst the first training session triggered a green dot while the individual was moving between 50˚ and 130˚ the fifth training session triggered a green dot when the individual was moving between 80˚ and 100˚. The decrease in bandwidth would aim to promote an improvement in coordinated movement at 90˚ after each session. The “Control” group did the same amount of trials but received no such feedback.
The results found that participants who received feedback were significantly better at maintaining a 90˚ movement for longer periods of time than the control group, whereas the control group did not show any improvement whilst doing the same post-training session.
The results therefore show that feedback is vital to learning a new task as the control group were unable to complete the movement task at the same level as the feedback group even though they received the same amount of time to practice the movement as the feedback group.

Perceptual coupling in rhythmic movement coordination: stable perception leads to stable action

The aim of this study is to test a new technique that allows comparisons to be made between movement measures of between-trail (perceptual) and within-trail (movement) variability within the same perception-action task and person.

Experiment 1

Three groups of 8 students took part. At first participants produced 0° with three practice trails (0:0, 0:180 and 0:90). For the next three trials the cross-modal phase relation was set to 0° (0:0). This was followed by a block of six trials with the crossmodal phase relation set to 90° (0:90). The next six trials set the crossmodal relation to 180° (0:180), followed by three more 0:0 trials. Finally, there were two blocks of four trials in which the instructions were to produce either 180° or 90° visually.

First, they analyzed the MVLW data from the consistent conditions. Pairwise comparisons indicated the main effect of phase condition was due to within-trial stability at 0:0 being higher than the other two conditions, the main effect of frequency was due to stability being higher at 1 Hz. An average 90:90 and 180:180 were not different from each other.

Second, they analyzed the MVLW data from the 0° visual target conditions. Pairwise comparisons showed that the main effect of phase condition was due to within-trial stability at 0:0 being higher than the other two conditions and 0:90 being more stable than 0:180.

A clear relationship existed between within- and between trial stability. The matching scale of the two measures is evidence supporting the hypothesis that the differential movement stability is being caused by the differential perceptual stability.

The main new result is that the 0° visual target stabilized movements that were at a non-0° phase relationship to the dot being tracked.

Experiment 2

The five conditions from experiment 1 where replicated plus two new conditions – 90:0 and 180:0. Pairwise comparisons showed that the 0° visual target conditions were more stable than the non-0° visual target conditions. An ANOVA on the non-0° visual target conditions revealed they did not differ in their stability.

Friday, 14 October 2011

Learning a coordinated rhythmic movement with task appropriate coordination feedback

The aim of this study is to produce a novel coordinated rhythmic movement (90˚ mean relative phase) using coordination feedback during post training. This allows the participant to learn a novel task. This should not alter in any way the perceptual information. It is said that people cannot produce 90˚ novel movements stably without training. They can only produce two stable coordination patterns without training, 0˚ and 180˚. So progression and learning has to occur, in this case coordination feedback is used.

10 participants were split into two groups of five. Group 1 (‘Feedback’) received coordination feedback during training; Group 2 (‘No Feedback’) received no feedback but an equal exposure to the task.

There were two assessment sessions (Baseline and Post-training) and five training sessions. Participants viewed a demo of the target relative phase and then performed five trials. In the five training sessions participants performed ten 20 sec trials with a target mean relative phase of 90˚. There was a computer-controlled dot situated above the person-controlled dot. The participants then used a joystick to move the dot at a specific mean relative phase. For the Feedback group feedback was provided by the colour change of the person-controlled dot from white to green when the participant was moving at 90˚, ± an error bandwidth. In the first session the error bandwidth was set to 40˚. Any performance between 50˚ and 130˚ triggered the colour change. The bandwidth was decreased in each session to 30˚, 20˚, 15˚ and 10˚. This will drive learning as the participant improves after each bandwidth. A colour change was used as the coordinated feedback because it is said that colour has no affect on movement stability. The No Feedback group also did 50 trials, but with no feedback.

A repeated measures ANOVA was used. The results found that participants who received coordination feedback successfully and significantly improved their ability to maintain 90˚ coordination. The No Feedback group showed no improvement at any mean relative phase. Coordination feedback does not alter or remove the visual information (relative direction). Unlike visual metronomes and Lissajous figures which do alter the perceptual information.

People do not tend to suddenly acquire 90˚, as they are unable to move at 90˚ long enough to allow the required perceptual learning. The control group in this experiment received extensive practice at 90˚, but no help identifying when they were moving correctly, so failed to learn this coordination.

Thursday, 13 October 2011

Perceptual Learning Immediately Yields New Stable Motor Coordination

This study is focused on the attainment and retention of coordinated rhythmic movements. Specifically, the study assesses the effect of perceptual learning in relation to the demonstration of the movement. Through previous studies, researchers have proved that movements at 0 º and 180 º are stable and can be spontaneously performed without much occurrence of phase variability. Movements at 90 º however, have exhibited an unstable result, concluding that this movement would have to be learned before attainment could be achieved.

The learning of a novel movement based on its stability is not simply attained through physical practise, relying solely on the limbs experience of the movement. Instead, perceptual consequences of the coordinated movement along with transformed feedback results in a non-0 º coordinated movement to be stabilised. Reasons as to why performance at 0 º is easily performed as opposed to other relative phases is due to the essential information being detected more promptly. Therefore, improvement in stability in novel coordination is the participants’ ability to detect essential information through his/her perceptual ability. This study’s prediction is that if the participant is able to improve his/her ability at detecting the essential information then an improvement in stability at 90 º will occur.

12 participants (22-54 years old), half of which were assigned to an experimental group and the other to a controlled group. There were two experimental tasks: two alternative forced choice judgments and coordinated rhythmic movement. Also included were assessment and training sessions. The assessment session included judgment trials and movement trials without feedback; and the training session consisted only of judgement trials with feedback. The controlled group did not participate in the training sessions and received no feedback. There were 21 different trial types regarding judgement trials- 10 different differences x 2 orders and a catch trial. Demonstration was given at the start of the assessment, without feedback throughout session. During the training session participants performed 12 blocks of “choose 90 º” with feedback; these were compared to four other phases. As sessions progressed, discrimination was made harder. If response was correct, they were told; if incorrect, they were given an example of 90 º. Performance during training determined whether participants progressed to a harder training session; however, after four repetitions, they were automatically progressed. During movement trials, force feedback feature was disabled and participants were seated comfortably controlling joystick without actually seeing it. To dots were displayed on the computer screen; top dot was under control of the computer and the bottom dot was controlled by the participant. The computer recorded joystick and computer controlled dots.

Repeated measures ANOVA of the judgement results revealed that participants learned as a result of the training they had received; showing that there was a significant difference for baseline vs. post training at 90 º, however, there was no significant difference when analysing 180 º. A repeated ANOVA was performed on the median proportion of time on task with the tolerance set at 20 º (movement task); two within subject factors were noted: phase levels and session levels. The study found that stability at 90 º improved for the experimental group after training was given. The experimental group showed a main effect of phase as well as an interaction between phase and session while the control group only showed an effect of phase.

This experiment shows that the perception-action couples aid the learning of a coordinated novel movement. This was determined through thorough testing on the experimental and control groups in which the control group exhibited no significant result without perceptual training. The study showed that once perceptual ability was improved, movement stability had been increased, which strongly supports the hypothesis that movement stability is a function of perceptual ability. Perception-action is a system in which there are informational and motor components which contribute towards the overall behaviour of the system.

Learning a coordinated rhythmic movement with task appropriate coordination feedback

The aim of this study is to develop and test a method of providing augmented feedback that could drive learning but not alter the informational content of the task. Ten participants split into two groups of five (one group received feedback and one group didn’t) took part in two assessment sessions and five training sessions. In the training sessions, they performed ten 20-s trials with a target mean relative phase of 90°, for a total of 50 trials. Feedback was provided to the feedback group by changing the colour of the person-controlled dot from white to green when the participant was moving at 90°, ± an error bandwidth. The error bandwidth faded; in the first session, it was set to 40° and was decreased in each session to 30°, 20°, 15°and 10° to drive learning.

A repeated measures ANOVA was carried out on the proportion time on task data (tolerance = 20°) with Session (2levels: Baseline, Post-training) and Phase (3 levels: 0°, 90°and 180°) as within subject factors and Group (2 levels: Feedback, No Feedback) as a between-subject variable. The group who received coordination feedback significantly improved their ability to maintain a 90° coordination. The No Feedback group showed no improvement at any mean relative phase.

This method demonstrated that it is effective at allowing people to acquire a novel coordination, and it does not change the overall perception action task dynamic. This method therefore will be useful in further studies examining the role of perceptual information or in studies that focus on the learning process.

The Timed “Up and Go” : A Test of Basic Functional Mobility for Frail Elderly Persons. Podsiadlo. D & Richardson. S.

The aim of the study was to assess the functional capacity in the elderly using a modified timed version of a previous test proposed by Mathias et al. The validity and the reliability of such tests has been questioned therefore a new scoring system was implemented as a result of the imprecise scoring systems used previously.

60 patients from a Geriatric Hospital in Montreal took part in the study, 23 male and 37 female, with a mean age of 79.5 years. Their instructions were to stand up from a seated position in an armchair (approximate seat height of 46cm) walk a distance of 3 meters, turn around and walk back to the chair and return to the seated position. 10 active volunteers over 70 years old were also tested and these were used as control subjects. All the other patients had been diagnosed with major medical problems such as Parkinson’s disease and osteoarthritis.

The results displayed a wide range of times amongst the 60 patients with major medical diagnoses. However, the 10 active elderly volunteers all managed to complete the timed “up and go” in 10 seconds or less. The times between 57 of the patients ranged from 10 seconds to 240 seconds. There were 3 patients who were unable to complete the task and a further 7 who started but could not finish the test. No relationship was found between the score from the timed “up and go” test and their medical diagnosis. The scores were then divided into less than 10 seconds, 20 – 29 seconds and over 30 seconds as in indication of how independent in basic transfers they were.

The timed “up and go” test is very simple in that it is easy to administer as it requires no special equipment or training. The test is reliable as the results showed little variance in their times scores either between raters or over time. However further investigation is needed with regards to the group described as a ‘grey zone’. The scores in the 20-29 seconds category vary widely, therefore making it difficult to clarify their balance, gait speed and functional capacity. The test is valid as it measures everyday life activities. It is also a good screening tool as it may reveal no improvement in the time scores, displaying a deterioration in functional mobility that a neuromuscular examination may be unable to tell us.

Wednesday, 12 October 2011

What is an ‘older adult’?

It may seem like a fairly simple question and as soon as it’s asked many of you will instantly conjure up an image of what you perceive an older adult to be. No doubt as you yourself get older, the image or perception of an older adult is also pushed back and gradually gets older.
So when does someone become an older adult?
Is it at retirement age? I would suggest not as people retire at different ages and for different reasons. Is there a milestone or magical age where we become an older adult? Again maybe not as time and ageing treats us all differently depending on our lifestyle and genetic make-up among other things. So does this leave some measure of cognitive and/or physical functioning, that once we reach or drop below we are classified as an older adult? This seems in some part logical but there appears to be no such standard for which one is considered old or young.
It therefore seems that as beauty is in the eyes of the beholder, so is the classification of an older adult. The reason I ask this is because with my current study and recruitment drive for participants, the boundaries for older are at best vague. Using pilot data the boundaries set for this study is 50-60 but is this right? In a review article by Voelcker-Rehage (2008) there are approximately 20 different age groups categorised as older adults. These range from 50-59 to 59-81 with the oldest set at 62-95. Of the age ranges set only two cover the same period of time and these are ages 60-69. At the largest end of the scale 33 years is the difference between the extremes of older adulthood. This is so varied that at the other end of the scale, Mark Zuckerberg (aged 27) the founder of facebook has been born, educated and created a global phenomena that gives him a personal wealth of approximately $17.5 billion with 6 years left. So it seems that so much can be achieved and changed in that period of time, that maybe 33 years is just too long.
This however, still does not answer the question... What is an older adult? The review article by Voelcker-Rehage (2008) suggests that various studies found declines through all these ages with the youngest older adult group of 50-59 showing declines in their abilities to learn. This coupled with the pilot data we have used suggests that the age range of 50-60 years old we have set is right. But are they strictly an older adult? Either way when exactly should the title or classification of older adult be used to describe a vastly varied group of individuals?

Voelcker-Rehage, C., Motor-skill learning in older adults - a review of studies on age-related differences. European Review of Aging and Physical Activity, 2008. 5(1): p. 5-16.

Tuesday, 11 October 2011

Motor skill learning in older adults - a review of studies on age related differences. Voelcker & Rehage.

The aim of the paper is to review studies that focus on age related differences in motor learning across life span, particularly those focused on older aged adults. Motor development; the growth of muscular co-ordination from being a child, is considered generally, yet the main focus is motor plasticity; which is the ability of the Central Nervous System to acquire different pathways for sensory perception or motor skills.

A large number of studies are considered, focusing on a number of different aspects of motor learning. For example, for motor learning of fine motor skills, accuracy, sub movements, life-span studies, force variability, and augmented feedback. The rest of the studies consider motor learning of gross motor skills. many of them are comparative between older and younger adults, highlighting the differences of how we learn as we get older.

The findings from the studies suggest that older adults are able to gain in terms of their performance, yet the extent to which plasticity varies with age has to be carefully considered. A common result in studies of motor function show that performance levels drop in older adults compared to younger adults, regardless of any learning gains. Learning and performance differences are related to the structure, complexity, difficulty and familiarity of the task. Fine motor skill studies showed that performance gain diminished in older adults, and that performance differences between the young and old increased with practice. However, for the Gross motor skills, the results were contradictory, as some studies showed the highest improvement in older adults and others in the young.

A general overview of the findings are that decreased motor skill learning gains were interpreted as an age related performance loss in older adults, and occur due to a reduction in cognitive or motor plasticity. The causes of this are due to neuro-physiological changes; reduced nerve conduction and reaction speed, increased lateralization, diminished inhibition processes, and diminished tactile sensitivity. Despite these changes, there are considered to be compensatory processes in the cortical and sub cortical function that allow maintenance of performance. Brain imaging of the prefrontal , medio-frontal frontostriatal networks, which all relate to attention, showed age related decline.

In summary, all studies showed that performance does decline with age, yet considerable performance gains can still be seen, and that from the life span studies, we can see that decreases that occur in motor plasticity in older age can also occur in younger and middle aged adults.

The timed "up and go": A test of basic functional mobility for frail elderly persons. Podsialdo.D & Richardson.S.

The aim of the study was to assess physical mobility in the elderly, using a reliable method. Many other tests had already been developed, yet there seemed to be problems in terms of validity and reliability.

The method used was to see how long it took a frail elderly patient to stand up from an armchair (approximately 45cm), walk 3 metres, turn round, walk back and sit again. 60 patients were observed from a Geriatric Hospital in Montreal. 23 men and 37 women took part, and the mean age of the subjects was 79.5. All participants were aged between 60 and 90. 10 were considered healthy and active, and were aged over 70. The rest were affected by one of the following; A cerebral vascular accident, Parkinson's disease, rheumatoid osteoarthritis, cerebellar degeneration, post surgical hip fractures or general deconditioning.

The results showed that all the 'healthy' participants performed the test in 10 seconds or less. Time scores ranged between 10 and 240 seconds in 57 patients, as 3 were unable to even perform the test. 7 participants began the test but didn't have the stamina to finish. The results showed no relationship between the scores of the test and their diagnosis.
The hypothesis was supported by the results, in the fact that the timed "up and go" score correlated with patients scores on balance, gait speed and functional capacity.
The patients were divided in to 3 groups depending on their score. Those who took less than 20 seconds were considered independent, and could do everyday task without help, climb stairs, and leave the house alone. The second group consisted of those who took between 20 and 29 seconds to complete the task , who were considered mostly independent, needing help in areas such as getting off the toilet etc. The final group was those who took 30 seconds or more to complete the task, and these were considered dependant as they struggled getting up and walking without assistance.

The test proved to be practical, in the sense that it was simple to carry out, no special equipment was needed and it was quick. It was also reliable, as it gave a good indication of an individuals physical mobility, correlating with scores for gait speed and balance tests.
Those who scored lower than 30 and more than 20 were harder to categorize into a certain group, as such variation was seen in their tests for balance gait speed and functional capacity, so further assessment was needed to clarify their functional level.
If this test were to be used at the beginning of an examination, they could save a lot of professional time as irrelevant questions and tests could be eliminated and can focus on the specific area causing the issue.
As a descriptive tool it is good at describing level of functional capacity, it is quick and easy to carry out and has been proven to be reliable and valid.

Learning to throw maximum distances: summary

The aim of this study was to find out how changes in object size and weight alter during the process of learning to throw, and also how do these factors affect throwing once the skill has been aquired.

This was done by testing 18 female students, who were capable, but had little previous experience of overarm throwing. They were split into 3 groups, each having a different set of objects to throw, one group had objects of constant density, one group objects of constant size, and the other threw objects of constant weight. The study involved a pre-test, training period, and post-test throwing trials. Three criteria were measured; Throwing distance, angle of release and speed of release.

The results of this study state that overall, in all 3 categories, throwing distance improved, although the way in which they improved was varied. Throughout practice, the increasing distances being thrown were affected by the objects in the practice set. This suggests that the physical properties of the objects did play a part in the outcome of the distances thrown.

The angle of release results did not show significant mean changes in angle of release. The average angles of release remained close to 33 degrees in all categories, through all training and testing, which is in turn close to the optimal angle of 36 degrees as found in previous studies.
However, upon examining the variability of the angle of release showed that angle of release did become more consistent throughout practice. This was calculated by the standard deviations from the first and last weeks of practice, and a 3 - way mixed design ANOVA conducted on them.
In constant the density and constant weight categories, the smaller the object showed a greater variability in release angle. The constant size group showed only variations in object weight and showed no object effect, showing that the size of the object played little part in angle of release.

Finally, speed of release increased up to 50% throughout practice but each category displayed a different pattern. Separate ANOVAs were performed in order to determine the effect of objects on release speed in each category and practice week. With practice, release speeds were increasingly affected by objects for all groups. Tukey HSD post-hoc analyses showed that consistently greater release speeds came from the lighter objects in the constant density and size categories. The lightest object was thrown with the highest speed. In the constant weight group however, release speed increased consistently regardless of the size of the object. This suggests that release speed varied with object weight but not object size.

It was found that improvements in throwing performance were mainly due to an increase of release speeds. Analysis found that release speeds varied with object weight but not size.