MRC PinPrick User manual

PinPrick Stimulator Set
Tactile stimulators for
quantitative sensoric testing
(QST)
MR compatible version
User manual

1. Intended use
The “PinPrick” or punctate nee le stimulators enable the application of repro ucible
tactile/mechanical stimuli on the human skin. They are manually applie on ifferent areas of the
bo y. The stimulation is solely base on the force of freely movable weights insi e the gui ing tubes.
The ifferent weights result in ifferent stimulus intensities. One set inclu es seven PinPrick
stimulators with logarithmically staggere weights. The tips of the PinPrick stimulators have a
uniform geometry.
In a ition, three ifferent stimulators for light an stroking tactile stimuli are provi e .
By means of the ifferent stan ar ize stimulators a quantitative sensoric testing (QST) of the
in ivi ual tactile/mechanical sensitivity of pain gets possible. The uniform nee le geometry an the
efine weights guarantee the comparability of test results with ifferent persons an by ifferent
operators.
This user manual escribes the parts an the application of the PinPrick stimulators an the
accessories.
MRC Systems GmbH version 3 – 25.07.2013 page 2 of 13
2. Safety instructions
•The main risk of the PinPrick stimulator application is the uninten e penetration
of the nee le through the patient's or subject's skin. The stimulators are esigne
in that way, that a penetration of the skin shoul not occur even with the biggest
weight if the instructions in this manual are consi ere especially with respect to
han ling an cleaning.
•Do not touch any injure or morbi skin with the stimulators.
•Do not use more than 256 mN if you apply the PinPrick stimulators in the face.
Do not use more than 128 mN uring win -up measurements in the face.
•Do not push the PinPrick stimulators onto the skin. Instea let them act by means
of the weight alone. Otherwise you coul unintentionally penetrate the skin,
especially if you apply the biggest weight. Please take care not to touch the skin
with the gui ing tubes.
MR compatible version:
•The stimulators are ma e of materials that can be use insi e the bore of MRI
scanners uring imaging. However, they inclu e metallic parts an can experience
forces ue to the magnetic an electric fiel s in the scanner. Therefore, the
stimulators shoul not be let loose whenever they are close to the patient or
subject.
•The nee les are ma e of titanium which is a less firm material compare to
stainless steel. Thus, please take care not to ben the nee les or amage the tip.

3. Set components
•7 ifferent PinPrick stimulators for ifferent stan ar ize stimuli
•set for light tactile stimuli:
•brush: SenseLab™ Brush-05
•cotton bu : Böttger 09.143.9105
•piece of cotton wool (Q-tip) attache to an elastic plastic strip
•metronome use as a clock uring win -up measurements: Korg MA-1
•box
•user manual with test certificate
Figure 1: Complete PinPrick stimulator set
MRC Systems GmbH version 3 – 25.07.2013 page 3 of 13
metronome
pinprick
stimulators
stimulators
for light
tactile
stimuli
This area is
intentionally left
free to make
sure that move
out nee les are
not eforme .
Please o not
place any
objects into this
compartment.
Please note that the metronome an the brush are not MR-compatible. They shoul
not be taken into the MR cabinet.

4. Instructions for use
4.1. Before the first use
Before you use the PinPrick stimulators for the first time you shoul familiarize yourself with their
behaviour. For this purpose carefully take the „64 mN“ stimulator out of the box by han ling it
approximately in the mi le of the gui ing tube. First keep it in a preferably horizontal position.
Then move it slowly into the vertical an experience how the nee le slowly sli es out of the gui ing
tube by means of the weight. In the maximum position the nee le protru es about 25 mm out of the
tube before it is blocke by an internal stop.
By swaying the stimulator between the vertical an the horizontal orientation you can sli e the
nee le in an out of the tube.
Repeat this proce ure with all PinPrick stimulators first to experience the sli ing characteristics of
each stimulator, secon to check if all nee les are moving smoothly.
4.2. Correct application of the PinPrick stimulators
The significance of the pain threshol etermination with PinPrick stimulators critically epen s on
their repro ucible application. The following aspects are of special importance in this context:
1. a comparable contact area between tip an skin
2. a consistent effective weight
3. a comparable movement of the nee le onto the skin
The first two aspects are intuitively clear, since they have a irect influence on the person's
sensitivity. The repro ucibility is achieve by the uniform tip geometry an the calibrate weights.
However, in or er to actually apply the i entical tip geometry an the correct weight you have to
apply the stimulators in upright orientation an orthogonal irection to the skin.
The thir aspect shall be further explaine by figures 2 an 3. The figures show the forces which
have been measure by a force sensor when the PinPrick stimulators have been applie with ifferent
velocities an in ifferently swinging movements. It gets obvious that the effective force strongly
varies with the movement characteristics. Therefore, please take care for a smooth an uninterrupte
movement of the stimulators onto the skin.
MRC Systems GmbH version 3 – 25.07.2013 page 4 of 13
The nee les of the PinPrick stimulators are elicate mechanical components that can
be easily eforme by incorrect han ling an /or tilte application of a force. Please
o not press them transversely onto har objects. Please o not let them fall own. If
a nee le is anyhow eforme , please contact the manufacturer before your next
application.

Force [mN]
Time [s]
Force [mN]
Time [s]
Figure 2: Diagram of forces resulting from different movement velocities of the PinPrick
stimulators (single stimulus application). In the upper recording the stimulators of
4 mN and 25 mN have been applied correctly. In the lower recording the 25 mN stimulator
generated an unintended impulse since it was applied with too much power.
MRC Systems GmbH version 3 – 25.07.2013 page 5 of 13

Force [mN]
Time [s]
Force [mN]
Time [s]
Figure 3: Diagram of wind-up measurements with correct (top) and too swinging (bottom) power.
MRC Systems GmbH version 3 – 25.07.2013 page 6 of 13

4.3 QST applications
The stimulators are use for ifferent quantitative sensoric testing (QST) proce ures, as
recommen e by e.g. the German Research Network on Neurophathic Pain (DFNS) or other
European collaborations.
a) Determination of the mechanical pain threshold
The stan ar ize PinPrick nee les enable the etermination of the mechanical pain threshol by
means of a mo ifie metho of limits. For this purpose the geometrical average of the mechanical
pain threshol is calculate from usually five series of ascen ing an escen ing stimulus intensities.
Literature:
[1] Chan et al., 1992
[2] Greenspan an McGillis, 1994
[3] Hampf et al., 1990
[4] Ziegler et al., 1999
b) Determination of the mechanical pain sensiti ity of the skin and the mechanical allodynia
with mo ing stimuli
Here, the stimuli are applie in a balance series. After etermination of the stimulus/response
function you can fin out whether or not there is a hyperalgesia or a hypoalgesia or a mechanical
allo ynia.
The stimulators for light tactile stimuli are move in a single stroking movement over the skin (1-2
cm in length). Please apply the cotton wool in that way that the plastic strip is slightly bent. The
elastic force of the plastic strip was esigne in that way that the resulting pressure will then be in a
range of 100 mN. The Böttger cotton tab was selecte to enable a smooth force of about 3 mN in
stroking application. The stimulation intensity of the Brush-05 is in the range of 200-400 mN.
The patients or subjects shall verbally rate the stimulus intensity with a number (0 – 100). Here, „0“
stan s for „no pain“, which is not the same as „not notice “. If a stimulus is not recognize at all it
shoul be marke as „-“. „100“ correspon s to the maximum pain which can be imagine by the
MRC Systems GmbH version 3 – 25.07.2013 page 7 of 13
•The nee le shoul alrea y be in the outwar position before the PinPrick
stimulators are applie onto the skin. Therefore, move the PinPrick stimulators in
the upright position before the application. Move them in your han so that the
weight sli es up an own in or er to release any resistance. Otherwise, if the
nee le sli es out of the gui ing tube in an uncontrolle manner you can cause
lesions of the patient or subject, a eformation of the nee le, an /or amage of
the nee le's tip.
•Always place the nee le onto the skin in upright orientation. Otherwise you will
apply another effective weight or another tip geometry as esire . In that case, the
comparability of the measurements will be affecte .
•Place the PinPrick stimulators in a smooth movement onto the respective area of
the skin. Swinging placement can affect the effective force impact.

person. as „-“. „100“ correspon s to the maximum pain which can be imagine by the person.
Literature:
[1] LaMotte et al., 1991
[2] Ziegler et al., 1999
c) Wind-up
In this test a single stimulus is applie by means of the 256 mN PinPrick stimulator. Then - after a
perio of 10 secon s – a series of ten i entical punctate stimuli with a frequency of 1 Hz is applie in
the same skin area. The size of this area shoul be about 1 cm². Imme iately after the single stimulus
an again after the subsequent series of stimuli a summarizing rating is performe by means of a
numerical scale. From the recor e rating of the stimulus intensity the ratio between the rating for
the single stimulus an the series of stimuli is calculate . This is usually one in five repetitions. The
geometrical average of all ratios is the “win -up” value.
Literature:
[1] Price et al., 1977
[2] Magerl et al., 1998
More information about QST applications can be foun on the website www.neuro.me .tu-
muenchen. e/ fns/patienten/QST.html.
5. Dinsinfection and maintenance instructions
5.1 Disinfection, sterilisation
The application of the PinPrick stimulators is a non-invasive proce ure. We have alrea y in icate in
the safety instructions that there is an improbable resi ual risk of penetration through the skin.
Therefore, as an a itional safety measure for minimizing the risk of infection, you shoul clean the
nee les before each application. Please use an appropriate isinfection spray.
For sterilisation we recommen to use chemical sterilisation.
Tests have shown that it is also possible to use heat sterilisation in the autoclave. However, in this
case the last step of the process has to be a rying step. Otherwise the sli ing characteristics of the
PinPrick stimulators can be affecte .
MRC Systems GmbH version 3 – 25.07.2013 page 8 of 13
•The PinPrick stimulators shoul be isinfecte before each application.
•The nee les of the PinPrick stimulators are elicate mechanical components that
can be easily eforme by incorrect han ling an /or tilte application of a force.
Please o not press them transversely onto har objects. Please o not let them
fall own. If a nee le is anyhow eforme , please contact the manufacturer before
your next application.

5.2 Maintenance
Please take care for a generally clean status of the stimulators. Keep them in the box inclu e in
elivery. Contaminate stimulators shoul be cleane with a ry cloth. Please pay attention that
1) no liqui is entering into the gui ing tubes, since this can affect the sli ing characteristics
2) the nee les are not eforme
MRC Systems GmbH version 3 – 25.07.2013 page 9 of 13
•If you observe any resistance or unusual noise uring the application of the
PinPrick stimulators the sli ing surface of the weight insi e the gui ing tube coul
be contaminate or amage . In that case another effective weight as esire will
act on the skin. Therefore, you shoul once again check the respective stimulator.
If you can not restore the original behaviour by repeate reciprocating the
stimulator you shoul contact the manufacturer.
•Steam sterilisation can change the sli ing characteristics of the mechanical parts
an therefore the effective weight. The friction force can even increase in that
extent that the weights o not move freely anymore. Please consi er the notes
regar ing isinfection an sterilisation in this user manual. Therefore please check
the sli ing characteristics of the stimulators after each sterilisation before you
apply them to the skin.

6. Technical data
stimulus intensity PinPrick stimulators:
brush: SenseLab™ Brush-05:
cotton bu Böttger 09.143.9105:
cotton wool (Q-Tip) on plastic strip:
8, 16, 32, 64, 128, 256, 512 mN
~ 200-400 mN
~ 3 mN
~ 100 mN
All weights have been checke before elivery by means of force sensors.
nee le / tip geometry flat contact area ( iameter 0.25 mm)
ra ius of curvature: 5 (+0, -5) µm
length of nee le: 19.5 mm
material: titanium, support: PEEK (MR compatible version)
gui ing tube: iameter: 11 mm (MR compatible version)
material: titanium (MR compatible version)
weight: set with 7 PinPrick stimulators: 960 g
metronome: Korg MA-1, see the user manual in the metronome packing
Figure 4: Recording of forces from left to right:
cotton bud Böttger 09.143.9105, Q-Tip on plastic strip, and
SenseLab™ Brush-05
MRC Systems GmbH version 3 – 25.07.2013 page 10 of 13