The test-dose to ascertain whether the patient will respond and benefit from a pump implant to deliver ITB has been likened to the analogy of a “light switch”. A simple injection of ITB is given to simply see whether there is a response or not, in the same way as flicking a light switch, the room is flooded with light or it is not. The implantation of the programmable SynchroMed II pump using the same analogy is the “dimmer switch”. The medical team is able to determine exactly how much ITB to deliver to best manage the spasticity, i.e. how much light to flood the room with.

The test-dose always happens in a hospital environment allowing the medical team to fully care and assess the patient; this procedure may involve a short in-patient stay.

There are many ways that the test-dose is performed unique to the ITB centre and may include repeated single injections through a needle directly into the intrathecal space or the surgical implant of a catheter through which injections can be made. Whatever the method, only one injection can be made per day of a determined dose to see if there is a response or not. If there is no response to the first injection dose then repeated injections of higher doses can be made during the following days until a response or no-response is seen.

During the test-dose the child may experience brief symptoms of the following side-effects:

• Overly loose muscles

• Sleepiness

• Nausea and vomiting

• Headaches

• Dizziness

You should not be worried about these side-effects if they should occur, nor should you think that this is what is to be expected if the pump is implanted. Since the pump is fully programmable it allows the medical team to slowly and accurately titrate the ITB dosage to manage the spasticity whilst avoiding these side-effects.

The peak maximum effect of a single dose is around 4 hours after the injection and it is at this time when the critical evaluation assessments are made to determine the effect on the child's spasticity.

Once a positive effect is seen on the spasticity a thorough discussion between the patient, parent and medical team will determine whether ITB Therapy is the right option to proceed to pump implantation.