1. Feasibility and validity of a wearable
GPS device for measuring outings
after stroke
Dr Annie McCluskey
with A/Prof Louise Ada, A/Prof Cath Dean, Janine Vargas
Faculty of Health Sciences
Contact:
annie.mccluskey@sydney.edu.au

2. The Problem
Self-Report Methods:
 Diary/calendar
-
Burdensome; time consuming
Potential to over/under report outings
Objective Methods
 Pedometers, accelerometers etc
-
May miss valuable data (vehicle journeys)
 Global positioning system (GPS):
-
Less costly than observation
Used to measure mobility and wandering - people with dementia
Accuracy and feasibility unknown in stroke population
2

3. The Approach
 Prospective cohort design
 Stroke sample (n=20):



Mean 43 mths post stroke (SD 20)
70% male
Walking performance (6MWT):




Mean distance: 288m (SD 96), range 106m-494m
Mean age: 67 yrs (SD 12)
Drivers: 5% (n=1)
Public transport: 55% (n=11)
3

4. EZ-23 Personal Tracker (www.ezy2c.com)
On/Off button
Main screen

5. GPS signal obtained ~ every 2 mins
= 1 outing

6. Data Collection
 GPS device
= 7 days
 Diary
= 7 days
 Observation
= Half-day
6

7. Results 1:
Equipment Failure
Problem
Faulty GPS device = 3/5
60%
Faulty battery chargers = 8/15
50%
7

8. Results 2:
Human Error
Problem
Thought device was on (it wasn’t) = 11/20
55%
Forgot to switch device on/ recharge = 4/20
20%
8

9. Results 3:
Data Loss
215 of 1680 hours
over 7 days
= 13% data loss
(= 87% GPS data recovery)
9

10. Results 4: Number of outings
(beyond front gate, n=20 people)
Observation
Diary
GPS
Total (7 days)
N/A
159
133
Mean (7 days)
N/A
8.0
6.7
Mean (Half-day)
0.7
0.7
0.6
10

11. Results 5:
Comparison with Observation
Level of Agreement †
Method
Diary
% Exact
94%
89%
% Close *
†
GPS
100%
100%
Over a half-day compared to observation
* Within 1 outing
11

12. Conclusions
 Good agreement/accuracy
 Feasible for people with stroke to use
 Real-time monitoring required: Google maps
 Clinical implications:
 Diary is a valid self-report measure of daily outings
 Measure of change in community rehabilitation
 GPS now being used in the ‘Out-and-About’ Trial