Comparison of the non-invasive intracranial pressure Headsense monitor vs lumbar cerebrospinal fluid pressure measurements

Intracranial pressure (ICP) and intracranial hypertension
ICP is the pressure inside the skull and thus in the brain tissue and
cerebrospinal fluid (CSF). ICP is measured in millimeters of mercury (mmHg) or
cm H2O and, at rest, is normally 7-15 mmHg for a supine adult, and becomes
negative (averaging *10 mmHg) in the vertical position. An increase in pressure
can cause headache, however most headaches are not the result of an increased
intracranial pressure. In case of a suspected intracranial hypertension
patients undergo a lumbar puncture with CSF pressure as a marker of ICP. A
lumbar puncture is an invasive and sometimes painful procedure, which causes
post-dural puncture headache in up to 20% of patients. Thus, there is a demand
for a non-invasive and accessible technique that can assess ICP in patients.

New non-invasive ICP Monitor from Headsense
The HeadSense device is based on advanced signal analysis algorithms that
analyze an acoustic signal that is generated by the device. The acoustic signal
is transmitted using a small transmitter, placed in the patient*s ear, and
picked up by an acoustic sensor placed in the other ear. The signal is then
analyzed using proprietary algorithms, and the ICP value is displayed to the
user in mmHg which is the medical standard units for ICP measurement. (see
appendix for comparison of invasive and non-invasive ICP measurements).

Primary Objective
To measure the agreement between ICP (through Headsense monitor) and lumbar CSF
pressure (through a lumbar puncture).

In this study we will prospectively collect relevant clinical data on 20
neurological patients who are being referred for an elective lumbar puncture
(eg. suspected multiple sclerosis, raised intracranial hypertension etc). Each
enrolled patient will be monitored in parallel to the lumbar puncture with the
HeadSense*s ICP monitor. Subjects who meet the study*s inclusion and exclusion
criteria will be enrolled in the study.

Step 1: 10 minute measurement of Headsense monitor. Once the patient is
inclined with his upper body 30 degrees to the bed the pressure values, the
clinical procedure can begin. The device must be preset in a continuous
monitoring mode. The continuous monitoring allows a loop of measurements for an
unlimited time in a rate of four measurements per minute.

Step 2: 10 minute measurement of Headsense monitor in supine position.

Step 3: Patient will be placed in a left lateral position. The lumbar puncture
will be done using a 22 gauge atraumatic lumbar puncture needle (e.g., Pajunk
Sprotte needle) The CSF pressure will be measured using a standard column
manometer.

Step 4: 10 minute measurement of Headsense monitor in supine position.

Lumbar puncture and headsense measurement will be done by two different doctors
and they will not share measurement values during the procedure.
After the study the patient*s ears will be examined for internal ear infection
or irritation that might be caused by the ear buds. Patient adverse events will
be documented on the case report forms in case they occurred and the family or
advocate of the patient will be informed. In case of clinical relevant adverse
events appropriate clinical action will be taken.
As the procedure does not affect the patient management, there is no need to
provide any specific medical care related to the trial. Patients will receive
the relevant clinical care related to their clinical management, without any
consideration to their participation in the trial. Data integrity will be
verified by the company*s representative to ensure that there is no missing,
unused, and spurious data.

Procedure lumbar punction:
This is a routine procedure done several times per day in hospital. The patient
is usually placed in a left lateral position with their neck bent in full
flexion and knees bent in full flexion up to their chest,The area around the
lower back is prepared using aseptic technique. Once the appropriate location
is palpated, A spinal needle is inserted between the lumbar vertebrae L3/L4,
L4/L5 or L5/S1. The stylet from the spinal needle is then withdrawn and drops
of cerebrospinal fluid are collected. The opening pressure of the cerebrospinal
fluid will be taken during this collection by using a simple column manometer.
The procedure is ended by withdrawing the needle while placing pressure on the
puncture site. After the procedure patient will rest for 15 minutes. The same
a-traumatic spinal needle (22Gauge) and manometer will be used in every centre.

Procedure registration with the Headsense monitor:
The front-end (ear buds) will be placed on the patient head, with each sensor
placed inside the patient*s ear. It is very important to tighten the headsets
to the patient*s ears properly. It is also worth noting that there is a right
and left headset. There are three headset ear tips, which come in three sizes.
They are used in order to ensure full adherence of the headset to the ear
canal. The most suitable ear tip for the patient should be used in order to
allow a good quality of signal transfer. While placing the headset in the ear,
the headset should be first placed in an axial position in which the headset*s
wire is perpendicular to the patients* spine. Then, the headset should be
turned 90 degrees, so the headset*s wire will be perpendicular to the eyes.

As the device is non-invasive and radiation free, it has a very low risk. On
the other hand the benefits that can be achieved from using a non-invasive and
cost effective ICP monitor are very significant for improving future patient
care and management. Therefore this trial offers a very low risk with a
potential for high benefit should the technology be validated and be used in
daily practice.

Safety information
So far the device has been tested on >100 patients without any negative side
effects. The sound level is only 10Db so hearing damage is not likely. Allergic
reaction caused by skin contact with the device (the parts that are attached to
the skin) are taken from an off the shelf stethoscope, so this is also very
unlikely to happen. The device is CE certified .

Patient load.
The patient load is very minimal. Patients undergo twice a measurement of 10
minutes prior to the lumbar puncture. Both times in the supine position with
the first measurement , which the head is inclined 30 degrees and the second
measurement just in supine position. . Then the treating physician will then
perform a lumbar puncture according our local protocol.. Then the last
measurement of 10 minutes in supine position will be performed.