Exam text content

LTT-1800/1806 Exam 21.4.2008
Answers in finnish or english.

1. ECG work
a. Prove that the amplitude of potential in Goldberg's augmented lead (12-lead ECG
system) is 1.5 times higher than the potential in corresponding unipolar lead. Be
specific. (2 points)
b. Explain in details the basic reasons and principles for vectorcardiographic (VCG)
measurement. (4 points)

2. EEGwork
a. Electrode impedances are important in recording EEG. Why is this? (3 points)

b. If you are torecord VEPSs in poor measurement setting having large noise level, what can
you do to improve i) the recording situation and ii) the analysis of VEP data? (3 points)

3. Nerveimpulse velocity work

a. Youare stimulating i) a single neuron or ii) a bundle of neurons. In these two cases
what are the effects of the stimulation amplitude on the response strength and impulse
velocity? What are the differences between the cases and why? (3 points)

b. Ifthe velocity would be calculated as distance/time between one stimulation location
and the response location, would the velocity be accurate? Give reasons for your
answer. (time = time between stimulus and response ; distance = distance between
stimulus and response locations) (1.5 points)

What is the effect of using two stimulation locations, e.g.: upper arm, and lower arm,
and using the formula Adistance /Atime , on the accuracy of the calculated velocity?
(Adistance = distance between the two stimulation locations, Atime = difference of the
observed conduction time for the two stimulation locations ) (1.5 points)

4. Respiratory work

a) What do you mean by Lung Compliance (CL), the factors that determines CL, and what
information do we get by calculating CL. (2 points)

b) Define obstructive and restrictive lung disease? How they affect Forced vital capacity (FVC),
Forced expiratory volume in 1 second (FEV1), FEV1/FVC ratio and Total lung capacity (TLC)?
(4 points)