Case Study (from my troubleshooting files)
A new patient was seen for a second opinion about a funny sensation on their scalp and occasional tingling, heat sensation and minor shock-like sensation in the neck. The person had been having the sensations for about 6 months and told several times by their programmer that nothing was wrong and to ignore the sensations. On review of the history, the person had DBS for about 6 years and had experienced a very good outcome. Lately, tremor had been showing up in the hand occasionally and when the tremor came on it was quite bothersome and then would go away. Medications and general health was unchanged over the past year. There was one wedding and one funeral, but no undue stressors that persisted. No falls, no new hobbies and the Parkinson’s was otherwise stable. The stimulation had not been changed over the past year and the electrical checks were reported to be normal.
During the exam, the person did not have tremor and the stimulation appeared to be working properly. Touching the wires gently did not reproduce any shocks. The skin over the wires and battery was well healed. The electrical system check was normal. The person also appeared to be taking adequate medication. Based on the patient’s reports of odd sensations and occasional breakthrough tremor, I ordered a complete set of x-rays to examine the wires.
The x-ray was conclusive. The wire insulation was damaged and needed replacement surgery.
The main learning points from this case example is the patient knew something was wrong. Following the historical information can solve most DBS problems in one or two appointments. The odd sensations were very near the damaged wire and a simple x-ray revealed the problem. The wire was not completely broken so stimulation could still travel down the wire, but some of the electrical current could leak out into the tissue and cause tingling, heating and minor shock sensations. On more discussion, the patient’s care partner remembered a bump of the head several months ago.
The outcome of the second opinion: We replaced the damaged wire and the person regained good tremor control and no longer experienced odd sensations.
This story is one example from hundreds of patients I have seen for troubleshooting DBS problems. Most people (about 60%) require only a change in their stimulation settings. Hardware problems are not common (about 10%) but can cause a decline or loss of benefit that can be restored after an accurate diagnosis.