Most recent publication – Rapid Assessment of Gait and Speech

Surgical Neurology International

Sierra M. Farris, Monique L. Giroux

August 2, 2016

Rapid Assessment of Gait and Speech after Subthalamic DBS

Background: Describe a rapid assessment for patients with idiopathic Parkinson’s disease (PD) and deep brain stimulation of the subthalamic nucleus reporting worsening speech and/or gait problems.

Methods: We retrospectively reviewed 29 patients that had improvement in gait and/or speech within 30 min after turning stimulation off. Clinical data analyzed include unified PD rating scale motor scores and stimulation parameters before and after adjusting stimulation. All patients received electrode efficacy and side effect threshold testing. Stimulation parameters were adjusted to maximize efficacy, avoid side effects, and maximize battery longevity.

Results: Turning stimulation off revealed reversible speech and/or gait stimulation side effects within 30 min. Focusing on six factors revealed stimulation modifications that improved motor symptoms, eliminated stimulation side effects, and reduced battery drain. Primary stimulation parameters modified were cathode selection and pulse width reduction.

Conclusions: Stimulation-induced side effects impacting gait and speech can be identified within 30 min. A systematic evaluation can distinguish disease progression from reversible stimulation side effects and improve motor outcomes over the long term.

Publication is open access. Link.

Patient Guide to Solving DBS Problems

Deep brain stimulation is a complex treatment that requires time and attention beyond the typical medical appointment, especially when there are DBS problems. Decisions about stimulation changes are based on patient reporting of symptoms, medication dosing, examination and reporting from the care partner.  In some circumstances, I also use brain imaging as a factor when selecting stimulation settings. The following data is helpful to have when adjusting stimulation and I frequently ask my patients about most of these at each appointment:

  1. Three day symptom diary that includes the time of each medication dose.
  2. Medication list that is accurate in how medications are taken. (This may not match how the medication was prescribed)
  3.  Pre-surgical work up including symptom testing or examination off and on medication.
  4. Brain imaging.
  5. Time-line from the patient’s perspective that includes benefit, side effects, problems. (Critical to sort out problems)
  6. All past stimulation settings and corresponding effects. (Some of my patients keep a running list of settings and response)
  7. Comprehensive notes from the care partner or home video of symptoms.
  8. Open discussion about sources of stress that may interfere with or hinder benefit from stimulation.
  9. Reporting of other unrelated medical problems, new medications or non-prescribed substances.
  10. Lastly and potentially the most important is the patient’s comments on how things are going and if not going well, what could be the source of the problem.

Read about an unusual second opinion from my troubleshooting files.

DBS Outcomes – Advocating for better care.

In review of my DBS blog created in May 2013, the most common search that brings someone to the blog include speech and walking problems. My August 2013 post titled “Walking and balance is worse after DBS, What can be done” has been read over 2,000 times. Speech and balance problems also reflect the most common concerns from patients that have requested a second opinion for our DBS troubleshooting clinic.

Over the past 12 years, we have evaluated over 450 people seeking a second opinion about poor results. Patients arrive with the hope we will find a solution and feel the second or third opinion is their last hope. Investigating problems takes time and patience with a methodical approach. Insurance payers do not reimburse extended clinical assessments so the extra time is generally at our willingness to work pro bono. Most often, the ‘fix’ is a simple change in stimulation settings. Sometimes the placement of the probes in the brain could be better, and sometimes, the problem is disease progression. Broken wires and device malfunction have become less common over the past decade. Managing stimulation appropriately remains a predominate cause of poor results, even after all the years DBS has been FDA approved (1997).

Not all communities will have medical specialists to help when results are disappointing and professional politics or egos may limit referrals for second opinions. The majority of our calls for a second opinion are from patients or family members seeking out help on their own. So where can a patient turn for help when symptoms do not improve as expected or the results do not match the proposed benefits of DBS?  A person submitted a story about experiencing worsening speech and gait problems after DBS. I could read in her words a palpable distress of lost hope. Although DBS is a highly beneficial treatment, as a leader in DBS programming, there is an obligation to shed light on a persistent problem for patients with DBS that may have nowhere to turn.

As medical providers, we should not underestimate the negative impact , the loss and the persistent distress when DBS falls short of the promise that life will get better. When DBS fails the patient, the cause should be identified and quality improvement should be implemented to raise the bar of care for patients with DBS. We owe our patients the level of care they deserve when undergoing the risk of an elective brain procedure. We have an ethical responsibility to not engage in offering DBS to patients when neurological, surgical and/or programming skills are limited. 

I am often asked how to find a qualified DBS programmer and many of the patients seen for troubleshooting leave with an anxiety of what will happen when they return home. Unfortunately, there is no registry, certification or qualification for DBS programmers. The credentials vary and level of education nor years of experience guarantee competence in DBS. Stimulation may even be managed by device industry and non-medical personnel. This has been an ongoing issue since DBS was FDA approved and remains a quandary for patients, training programs and the healthcare system.

We are only seeing the tip of the iceberg as DBS is mentioned in the media as a hope for Alzheimer’s, Autism, stoke and depression as well as several other serious debilitating conditions. When time, research, medical training, experience and increasing volumes of implants have not led to a proficiency examination nor standard of care policy for DBS, the true benefits of deep brain stimulation will remain elusive for many patients and the number of poor outcomes is destined to grow.

Speech Quality & DBS

Speech & DBS

Speech Spectrogram
Speech Spectrogram – Computerized Voice Assessment

Speech changes are a common symptom of Parkinson’s, tremor or dystonia. The cause is multifactorial and typically speech changes occur very slowly over time. (This distinction is important.) Speech can also be altered by deep brain stimulation and is one of the most common stimulation related side effects and great source of patient dissatisfaction. Almost all speech disturbances can be reversed if the speech change is related to stimulation.

Other causes of speech problems after DBS can occur from the surgery such as bleeding (stoke) or tissue damage. These complications are uncommon but are serious and may involve more than just speech, such as walking and thinking. Having a stoke from other causes (high cholesterol, high blood pressure) can also cause speech problems and are unrelated to DBS.

Speech changes can also occur from too low or too high medication dose, dyskinesia, tremor, fatigue and illness. The vocal cords can be a source of voice change but is typically noticed prior to DBS and should always be assessed by an ENT physician specialist. A change in speech can be a sign of a serious medical conditions.

Stimulation dose is not much different than medication dose. Too little dose – not enough benefit, too high dose – side effects occur. Stimulation and medication are similar in that there is a maximum benefit and always a risk of side effect if the dose is too high.

Useful Tips: The following are some tips that patients can use to assist their medical provider in troubleshooting speech problems after DBS.

Before DBS:

  1. See a speech therapist for a computerized speech assessment – on medications. This is the benchmark for all future speech assessments after DBS.
  2. Optimize speech, posture and breathing for the best possible speech before surgery.
  3. Optimal speech depends on optimal medication if you have Parkinson’s.
  4. Make a recording of your speech to use later if needed to assess speech changes.

After DBS:

  1. Write down for you doctor when your speech was the best and when you first noticed a change. Some patients remember one appointment that resulted in speech slurring. I see some patients that tell me speech was good a couple years ago and then started to get worse. This could be disease progression or it could be from a gradual increase in stimulation intensity. The time-line will help determine what caused speech to change. Note how your speech changed, such as loss of volume, mumbling, stuttering or slurring. If you have a recording of your speech when it was good, bring it to your appointment.

How I assess speech changes in my patients after DBS:

  1. If the speech change occurs prior to turning on stimulation for the first time, I assess and monitor cognition. If the speech change is related to a change in verbal fluency (cognition), it may improve over a few months. Verbal fluency problems are related to finding the right word or completing sentences (language aspect of cognition) but commonly lumped into the speech category after DBS.
  2. If the speech change is after stimulation has been on, I set up an appointment to specifically assess speech. The patient should be On medications for the appointment. I use a simple assessment to establish a baseline by asking my patients to read the rainbow passage. I audio-record speech if the problem is complicated. I then turn off one side at a time. If speech improves with stimulation off, I adjust stimulation parameters to eliminate the speech problems. This is generally not difficult if the speech problem is from overstimulation.
  3. Almost always, the cause of the speech problem is too high stimulation intensity. This is a very reversible cause and reducing stimulation intensity can resolve almost all speech problems related to DBS. This assumes good placement of the electrodes in the brain. During DBS surgery, I talk with my patients to ensure speech is not being impacted to optimize electrode placement. (One very good reason to have DBS while awake)
  4. A common myth is that only the left side of the brain is involved in causing speech problems. This is not true. The left brain does control language for many people, but then so does the right brain in some. Language and speech are two very different functions controlled by very different areas of the brain.
  5. Tremor is one of the most common causes of pushing stimulation too high. I think this is most likely because we can see the tremor and tremor will increase with emotions and stress. Some patients and medical providers expect tremor to just stop instantly and if it doesn’t, stimulation intensity is increased until tremor stops, even when stimulation causes the leg to drag, the hand to cramp, speech to slur or balance problems. However, like with other symptoms, it takes time for stimulation to work. Over-stimulating will stop tremor quickly but will more than likely cause un-necessary speech problems and most importantly can also cause swallowing problems, falls and increased slowness and stiffness (like the tin-man). Having appropriate expectations for DBS and knowing the limits can help avoid stimulation side effects and symptoms that mimic disease progression.

Walking and balance is worse after DBS, what can be done?

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 sideeffects 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.