Page 11 - 2020 Spring CMTA Report

be particularly helpful in HMN fraction of a second. It’s best if the mildly uncomfortable, but for
and can determine if there is any patient can allow testing of at least some, particularly patients with
muscle involvement in HSN. one motor and one sensory nerve aversion to any needles, the needle
EMG can evaluate muscles that even if it’s uncomfortable. Sensory examination can be painful. The
are more proximal—above the nerves need less stimulation than good news is that if needle studies
knees and elbows—which are not motor nerves and are less painful. are done, there shouldn’t be the
easily tested with NCS. This can For CMTers, studies of the arms need to study many muscles.
be helpful, but rarely allows a may provide more information NCS and EMG can be
diagnosis of CMT. Because it is than the legs, but each case is dif- performed at any age, including
not always necessary for the EMG ferent. Relaxation techniques can infancy, but with children, the
portion of the EDX to be done, help reduce anxiety and pain. examination has to be modified to
the decision should be discussed The needles used in EMG account for their size and inability
with the treating doctor and elec- are very thin and sharp. They are to fully cooperate during the
tromyographer. disposable, so there is virtually no study. The 38 m/sec velocity
Electrodiagnostic studies are risk of infection. They are thinner that distinguishes CMT 1 and 2
not risky or dangerous and do not than the needles used for drawing cannot be used under the age of 2.
cause problems afterward, but blood and there is minimal risk of The examination in young chil-
they can be uncomfortable. The bleeding even if one is on aspirin. dren is usually brief and sedation
NCS requires electrical stimula- Anyone on a blood thinner should is not normally necessary. If a
tion, which is very brief but can bring it to the electromyographer’s child is from a family with known
be painful. Some CMTers have attention, but most muscles can CMT that has been diagnosed
nerves that are difficult to stimu- be tested even if the patient is genetically, then EDX may not
late, which can require higher taking Coumadin or other major be needed. If the child is symp -
amounts of stimulation. This may blood thinners. For most patients, tomatic, there may not be a need
be painful, but the pain lasts a the needle examination is only for any testing. h

SPRING 2020 THE CMTA REPORT 11