Biomedical Engineering Reference
In-Depth Information
•
Experiment 3: Subjects practiced their skills in placing checkers while they
were given the boards in random order.
Subjects
We are reporting results from five test subjects (3 male, 2 female; aged 25-
51 years) who were all practiced in the use of simulated phosphene vision
through their participation in other tests (reading tests and face/object recog-
nition) that did not involve object manipulation. Four subjects were normally
sighted; the remaining subject was severely visually impaired (legally blind) due
to a chemical burn of both corneas in early childhood.
All testing was done according to the tenets of the Helsinki convention. The
subjects were informed of the purpose and procedures of the experiment, and
read and signed a consent form approved by the IRB of the Johns Hopkins
University School of Medicine. In accordance with HIPAA rules the identities
of the test subjects were coded with numbers to mask their identities.
Results
To evaluate the results of the tests the following rules were applied:
1. Errors in counting tasks were “punished” by using the formula
FinalTime
=
UsedTime
+
Real number of squares - Counted number of squares
×
AverageTime
(1)
where
UsedTime
is the time measured with the stop watch,
Real number of
squares
is the number of white squares on the board,
Counted number of squares
is the number that was called out by the test subject, and
AverageTime
is the
calculated time it takes the test subject to count one white square on a board.
This
AverageTime
is calculated for every test subject respectively using the
formula:
Sum of time
Sum of squares
AverageTime
=
(2)
with
Sum of time
as the sum of the measured time for all the boards in the session
and
Sum of squares
as the total number of squares summed over all boards used
in the session.
2. To evaluate the “placing checker” parts of the experiments the following
approach was chosen:
Errors were divided into groups with their respective error values:
Search WWH ::
Custom Search