Steering Control and Looming Detection in Young Adults with DCD Y - - PowerPoint PPT Presentation

Steering Control and Looming Detection in Y Ad lt ith DCD Young Adults with DCD

Ri F d Oli i C h i P ll J h W Rita F. de Oliveira3, Catherine Purcell1, John Wann1, Damian Poulter1, Kate Wilmut2

1 Royal Holloway University of London, UK 2 Oxford Brookes University, UK

3 Royal Holloway University of London, UK, German Sport University Cologne

Research supported by the UK ESRC ES/F017650/1 & The Netherlands Organisation for Scientific Research

Looming Detection in Young Adults with DCD

• Looming usually indicates an approaching object
• What is the perceptual ability of DCD to detect looming?

p p y g

• Ability to detect an approaching car is a critical roadside skill

h d d l i h l bl d

• At what speeds are young adults with DCD no longer able to detect an

approaching car?

• Measured sensitivity to looming detection

in central and peripheral vision, under monocular viewing conditions

Looming Detection Thresholds for a Central Car

V = R ΘT * TTC2

.

0.32 0.34

Looming Thresholds

0 22 0.24 0.26 0.28 0.30 deg/s) 81

200ms

0.14 0.16 0.18 0.20 0.22 ing Thesholds (d mph

Did it get bigger? (Null trials for FP rate)

0 04 0.06 0.08 0.10 0.12 Loomi 392 235 196 N = 5 0.00 0.02 0.04

<5th 5th - 15th

TD mean & 95% CI DCD <5th now <5th DCD <5th now 5th 15th 5th 15th d >15th

• When centrally fixating, all individuals were able to detect an approaching car travelling at speeds

well above those likely to be encountered in the real world (>196mph)

TD mean & 95% CI DCD <5th now <5th DCD <5th now 5th-15th 5th-15th and >15th

Looming Detection Thresholds for a Peripheral Car

V = R ΘT * TTC2

.

0.46 0.48 0.50

Looming Thresholds

0.36 0.38 0.40 0.42 0.44 (deg/s) 56 62

200ms

0 24 0.26 0.28 0.30 0.32 0.34 ming Thesholds ( 84 mph 69 N = 4

Did it get bigger? Did the car grow bigger? Did it get bigger? (Null trials for FP rate)

0 14 0.16 0.18 0.20 0.22 0.24 Loom 0.10 0.12 0.14

<5th 5th - 15th

196 TD mean & 95% CI DCD <5th now <5th DCD <5th now 5th-15th 5th-15th and >15th

• When not fixating directly, the speeds at which all individuals were able to detect an approaching car

decreased (>56mph) compared to when individuals were directly fixating on the car (>196mph)

Looming Detection Thresholds for a Central Car with Simulated Observer Motion

V = R ΘT * TTC2

.

0 46 0.49 0.52

Looming Thresholds

49 0.34 0.37 0.40 0.43 0.46 deg/s) 55 62

200ms

0.19 0.22 0.25 0.28 0.31 ing Thesholds (d 107 mph

Did it get bigger? (Null trials for FP rate)

0 04 0.07 0.10 0.13 0.16 0.19 Loomi 138 235 196

• 0.02

0.01 0.04

<5th 5th - 15th

N = 5 TD mean & 95% CI DCD <5th now <5th DCD <5th now 5th-15th 5th 15th and >15th

• When in motion and detecting an approaching car centrally, overall the speeds at which individuals

were able to detect an approaching car (>49mph) were much lower than when individuals were

TD mean & 95% CI DCD <5 now <5 DCD <5 now 5 -15 5th-15th and >15th

stationary and directly fixating on the car (>196mph)

Looming Detection Thresholds for a Peripheral Car with Simulated Observer Motion

V = R ΘT * TTC2

.

1 70 1.80 1.90

Looming Thresholds

14 1 20 1.30 1.40 1.50 1.60 1.70 deg/s) 19

200ms

0 70 0.80 0.90 1.00 1.10 1.20 ming Thesholds ( mph 30

Did it get bigger? (Null trials for FP rate)

N = 3 0 20 0.30 0.40 0.50 0.60 0.70 Loom 38 98

(Null trials for FP rate)

N 3 0.00 0.10 0.20

<5th 5th - 15th

98 196 TD mean & 95% CI DCD <5th now <5th DCD <5th now 5th-15th 5th-15th and >15th

• The ability to detect an approaching car decreased considerably for all individuals when in motion and

not fixating directly on a car (~38mph) compared to when stationary and directly fixating (>196mph) T i i f il d hi lli f h 20 h

• Two participants may fail to detect an approaching car travelling any faster than ~20mph

How long does it take to cross the road?

• TTC fixed at 3sec – estimated length of time it takes to walk the width of a single lane

– good estimate for some – good estimate for some…

• … Not so good for others

6.50 7.00

Walking Speeds (normal)

5.50 6.00 4.50 5.00 Time (sec) 3.50 4.00 2.50 3.00

h h h N=5

TTC =

<5th 5th-15th

TD mean & 95% CI DCD <5th now <5th DCD <5th now 5th-15th 5th-15th and >15th

Conclusions

• It seems that in a simple looming detection task, young adults with DCD do

not have general perceptual difficulties in judging whether cars are not have general perceptual difficulties in judging whether cars are approaching

• The differences found in walking speeds have implications for the execution
• f a safe road crossing

– For example: A looming threshold that equates to being able to detect a car travelling at 60mph with 3 seconds to cross, would equate to not being able to detect a car travelling any f t th 22 h if it t k 5 d t faster than 22mph if it takes 5 seconds to cross