Unexpected declines in balance and walking are the two most common problems that result in dissatisfaction and seeking a second opinion after deep brain stimulation. Walking and balance problems jeopardize independence and can lead to injury from falls which calls for a serious investigation when mobility is challenged. We approach changes in mobility after DBS surgery in a step-wise manner to zero-in on the cause and to find solutions. Our process for troubleshooting mobility changes after DBS is outlined below.
- Understanding the time-line is the key to finding the cause.
Questions to ask yourself – Did walking or balance problems occur before DBS? Only after DBS? Only after a change in stimulation settings and/or a change in medications? Is there a new medical problem that could explain the walking and/or balance symptoms?
A New Problem: If walking and/or balance problems are new after DBS surgery, we want to be sure your medication dose is adequate. Reducing medications after DBS is expected but the speed of reduction will vary. Safe medication reduction depends on your sense of stability, baseline balance, physical health and fitness. Additionally, if mobility improves with medications, stimulation may also improve mobility. Setting appropriate expectations for stimulation is one of the most important steps to long-term satisfaction with DBS.
Another cause of new onset mobility problems can be related to stimulation. Stimulation induced side effects of leg dragging, gait freezing, gait slowness, staggering, spontaneous falling, foot drop, toe dragging or loss of postural control can occur from over-stimulation, inadequate stimulation settings or poor electrode position within the brain. In the setting of less medication use after DBS is stable, changes in effective stimulation can also cause a new mobility problem due to a sub-therapeutic medication dose or under-stimulation of the brain target. These are reversible causes of mobility problems.
Irreversible mobility changes can occur as a result of the surgery. Bleeding in the brain is a known and uncommon risk during DBS surgery and can cause stroke symptoms that include walking/balance changes. Lastly, there is a rare chance of permanent mobility disturbances after DBS surgery -even before stimulation is turned on. This is very rare, not understood and unpredictable at this time.
An Old Problem that is Rapidly Getting Worse: If walking and/or balance problems were present before DBS and noticeably increased after DBS, the source of the problem could be caused by medication changes, the stress of the surgery, a new medication side-effect or a new medical illness. Stimulation side–effects must be ruled out as a cause for worsening walking and balance. Stimulation induced mobility side effects may be accompanied by other stimulation side effects that include speech slurring or volume loss, facial spasm, swallowing problems, dizziness, blurred or double vision, visual waves phenomenon, tingling, numbness, surge sensation, slowness of movement, mood change or mental fog, muscle tightness or a new tremor. Sudden changes in mobility are typically tracked back to an event, such as an illness, medication or stimulation change. A fall or accident can result in damage to the DBS hardware system and this can cause a sudden worsening of mobility. A DBS check-up is very important in the setting of any loss of therapy or worsening symptoms, especially after a fall.
An Old Problem that is Slowly Getting Worse: Walking and balance requires complex control that involves multiple intact neurological systems. Changes in walking and balance are expected with Parkinson’s and the change is expected to be gradual and not sudden unless there are other factors. For instance, peripheral neuropathy, vitamin B12 deficiency, hypothyroidism, joint pain, spine problems and cognitive declines are common causes for walking and/or balance changes as we age. Coupled with the progression of Parkinson’s, additional medical problems can compound or worsen mobility.
Treatment Approach: Physical therapy before and after DBS is very important even if mobility is good. There are subtle changes with any neurological condition that can be restored or improved with skilled neuro-physical therapy. Finding a medical provider that is a good listener and open-minded will go a long way in solving a change in mobility after DBS. A comprehensive approach to your medical care before and after DBS will help to optimize mobility over your life-time. Exercise continues to be important in your treatment after DBS surgery. Weight gain is a possibility after DBS which increases the importance of starting and/or maintaining an exercise program. Perhaps the most important take-home point for this post: As Parkinson’s progresses, resisting the urge to increase stimulation intensity for walking/balance problems is critical to avoid over-stimulation side effects that can directly worsen walking and balance.