STN-DBS frequency effects on freezing of gait in advanced Parkinson disease
HanaBrozova, Mount Sinai School of Medicine, 5 East 98th Street, Box 1139, New York, NY 10029hana.brozova@lf1.cuni.cz
Isabelle Barnaure, Ron L. Alterman, and Michele Tagliati
Submitted June 26, 2008
We read with interest the article by Moreau et al. describing a new treatment for severe freezing of gait (FOG) in advanced Parkinson’s disease (PD) by using 60 Hz STN-DBS. [1] We reported that stimulation of the STN with lower frequencies produced a positive effect on gait and speech but symptoms insufficiently improved or even worsened after several years of high frequency (HF) STN-DBS. [2]
We switched 12 PD patients with persistent gait difficulties to 60Hz stimulation after a mean 4.3 years (range 2-8) of bilateral HF STN-DBS. Seven patients had FOG, six had postural instability and seven experienced falls. Three patients could not acutely tolerate the change in settings because of increased tremor (one), rigidity (one) and gait worsening (one). The remaining nine subjects (three women, six men) were followed open label. These nine subjects had a mean age of 66.8 (9.6 SD) years and a mean PD duration of 16.6 (5.0 SD) years.
ON-medication UPDRS scores were collected 8-12 weeks after switching to 60 Hz and compared to ON-medication scores obtained at higher stimulation frequencies. Significant average improvements were observed for the UPDRS-II subscale (3.9 points; p<_0.05 updrs-ii="updrs-ii" sub-items="sub-items" relative="relative" to="to" speech="speech" falling="falling" and="and" walking="walking" p0.05="p0.05" updrs-iii="updrs-iii" sub-="sub-" items="items" gait="gait" p0.05.="p0.05." postural="postural" instability="instability" _27-30="_27-30" worsened="worsened" in="in" two="two" patients.="patients." an="an" average="average" voltage="voltage" increase="increase" of="of" _1.3="_1.3" volts="volts" range="range" _0.7-2.5="_0.7-2.5" was="was" required="required" bilaterally="bilaterally" seven="seven" patients="patients" for="for" beneficial="beneficial" maintenance="maintenance" other="other" pd="pd" symptoms.="symptoms." p="p"/>The conflicting responses observed with regard to frequency suggests that lower frequency STN stimulation may not be the solution to all gait problems in advanced PD. In our limited experience, we failed to find distinguishing features between responders and non-responders.
The selection of proper candidates will be a challenge to the widespread use of 60 Hz STN- DBS. There was also dramatic speech improvement in some of our patients, as well as in some described by Moreau et al. [1] Therapeutic current spreading to the pedunculo-pontine nucleus may explain the beneficial effect of lower stimulation frequencies on gait, [1] but this mechanism would not underlie speech improvement.
As very low frequency STN stimulation improves verbal fluency [3], it is possible that in addition to new targets of stimulation, alternative programming strategies may be needed to optimize control of the complex symptoms of PD.
References
1. Moreau C, Defebvre L, Destée A, et al. STN-DBS frequency effects on freezing of gait in advanced Parkinson disease. Neurology 2008; Epub April 16.
2. Krack P, Batir A, Van Blercom N, et al. Five-year follow-up of bilateral stimulation of the subthalamic nucleus in advanced Parkinson’s disease. N Engl J Med 2003;349:1925-1934.
3. Vojtecki L, Timmermann L, Jörgens S, et al. Frequency-dependent reciprocal modulation of verbal fluency and motor functions in subthalamic deep brain stimulation. Arch Neurol 2006;63:1273-1276.
We read with interest the article by Moreau et al. describing a new treatment for severe freezing of gait (FOG) in advanced Parkinson’s disease (PD) by using 60 Hz STN-DBS. [1] We reported that stimulation of the STN with lower frequencies produced a positive effect on gait and speech but symptoms insufficiently improved or even worsened after several years of high frequency (HF) STN-DBS. [2]
We switched 12 PD patients with persistent gait difficulties to 60Hz stimulation after a mean 4.3 years (range 2-8) of bilateral HF STN-DBS. Seven patients had FOG, six had postural instability and seven experienced falls. Three patients could not acutely tolerate the change in settings because of increased tremor (one), rigidity (one) and gait worsening (one). The remaining nine subjects (three women, six men) were followed open label. These nine subjects had a mean age of 66.8 (9.6 SD) years and a mean PD duration of 16.6 (5.0 SD) years.
ON-medication UPDRS scores were collected 8-12 weeks after switching to 60 Hz and compared to ON-medication scores obtained at higher stimulation frequencies. Significant average improvements were observed for the UPDRS-II subscale (3.9 points; p<_0.05 updrs-ii="updrs-ii" sub-items="sub-items" relative="relative" to="to" speech="speech" falling="falling" and="and" walking="walking" p0.05="p0.05" updrs-iii="updrs-iii" sub-="sub-" items="items" gait="gait" p0.05.="p0.05." postural="postural" instability="instability" _27-30="_27-30" worsened="worsened" in="in" two="two" patients.="patients." an="an" average="average" voltage="voltage" increase="increase" of="of" _1.3="_1.3" volts="volts" range="range" _0.7-2.5="_0.7-2.5" was="was" required="required" bilaterally="bilaterally" seven="seven" patients="patients" for="for" beneficial="beneficial" maintenance="maintenance" other="other" pd="pd" symptoms.="symptoms." p="p"/>The conflicting responses observed with regard to frequency suggests that lower frequency STN stimulation may not be the solution to all gait problems in advanced PD. In our limited experience, we failed to find distinguishing features between responders and non-responders.
The selection of proper candidates will be a challenge to the widespread use of 60 Hz STN- DBS. There was also dramatic speech improvement in some of our patients, as well as in some described by Moreau et al. [1] Therapeutic current spreading to the pedunculo-pontine nucleus may explain the beneficial effect of lower stimulation frequencies on gait, [1] but this mechanism would not underlie speech improvement.
As very low frequency STN stimulation improves verbal fluency [3], it is possible that in addition to new targets of stimulation, alternative programming strategies may be needed to optimize control of the complex symptoms of PD.
References
1. Moreau C, Defebvre L, Destée A, et al. STN-DBS frequency effects on freezing of gait in advanced Parkinson disease. Neurology 2008; Epub April 16.
2. Krack P, Batir A, Van Blercom N, et al. Five-year follow-up of bilateral stimulation of the subthalamic nucleus in advanced Parkinson’s disease. N Engl J Med 2003;349:1925-1934.
3. Vojtecki L, Timmermann L, Jörgens S, et al. Frequency-dependent reciprocal modulation of verbal fluency and motor functions in subthalamic deep brain stimulation. Arch Neurol 2006;63:1273-1276.
Disclosure: The authors report no disclosures.