Effect of low-frequency deep brain stimulation on sensory thresholds in Parkinson's disease

Abstract

OBJECTIVE Chronic pain is a major distressing symptom of Parkinson's disease (PD) that is often undertreated. Subthalamic nucleus (STN) deep brain stimulation (DBS) delivers high-frequency stimulation (HFS) to patients with PD and has been effective in pain relief in a subset of these patients. However, up to 74% of patients develop new pain concerns while receiving STN DBS. Here the authors explore whether altering the frequency of STN DBS changes pain perception as measured through quantitative sensory testing (QST). METHODS Using QST, the authors measured thermal and mechanical detection and pain thresholds in 19 patients undergoing DBS via HFS, low-frequency stimulation (LFS), and off conditions in a randomized order. Testing was performed in the region of the body with the most pain and in the lower back in patients without chronic pain. RESULTS In the patients with chronic pain, LFS significantly reduced heat detection thresholds as compared with thresholds following HFS (p = 0.029) and in the off state (p = 0.010). Moreover, LFS resulted in increased detection thresholds for mechanical pressure (p = 0.020) and vibration (p = 0.040) compared with these thresholds following HFS. Neither LFS nor HFS led to changes in other mechanical thresholds. In patients without chronic pain, LFS significantly increased mechanical pain thresholds in response to the 40-g pinprick compared with thresholds following HFS (p = 0.032). CONCLUSIONS Recent literature has suggested that STN LFS can be useful in treating nonmotor symptoms of PD. Here the authors demonstrated that LFS modulates thermal and mechanical detection to a greater extent than HFS. Low-frequency stimulation is an innovative means of modulating chronic pain in PD patients receiving STN DBS. The authors suggest that STN LFS may be a future option to consider when treating Parkinson's patients in whom pain remains the predominant complaint.

Pain-Induced Beta Activity in the Subthalamic Nucleus of Parkinson’s Disease

“…We postulate that the ideal conditions for therapeutic effect in PRP occur when there is synchronicity in the β oscillatory representation of both painful and nonpainful sensations. This may underly the differential efficacy observed between LFS and HFS in modulating sensory and pain thresholds [11].…”

“…Reports on thalamic DBS for the treatment of neuropathic pain suggest that low-frequency stimulation (LFS) is beneficial for pain relief, while high-frequency stimulation (HFS) is less efficacious or may even exacerbate pain [10]. Studies have also demonstrated that LFS can result in a lowered heat detection threshold and an increased tolerance to mechanical pain in non-neuropathic PD patients [11]. However, the nature of the physiology underlying this phenomenon remains unclear.…”

Das idiopathische Parkinsonsyndrom und Schmerz – diagnostische und therapeutische Ansätze für ein herausforderndes nicht-motorisches Symptom

“…Bis dato ist unklar, ob der analgetische Effekt der STN-THS durch einen stimulationsbedingten schmerzmodulierenden Effekt oder allein durch die Verbesserung der Motorik bedingt ist. Zu berücksichtigen ist ferner, dass auch bis 74 % der Patienten unter STN-THS über neue und/oder an anderen Körperstellen auftretende Schmerzen berichten [59,60]. Ob diese krankheitsbedingt und stimulationsunabhängig oder durch die Stimulation mitbedingt sind, ist unklar.…”

“…Die STN-THS kann offenbar Schwellenwerte für die Erkennung thermischer [61] und/oder mechanischer Reize [57,60] verändern, vermutlich durch Beeinflussung der somatosensorischen Schleife. Die überwiegende Anzahl der Studien fand jedoch keine Hinweise auf eine Veränderung der thermischen oder mechanischen Schmerzschwellen [57,61], so dass eine Modulierung des zentralen Schmerzes durch die STN-THS nicht belegt ist.…”

“…Die überwiegende Anzahl der Studien fand jedoch keine Hinweise auf eine Veränderung der thermischen oder mechanischen Schmerzschwellen [57,61], so dass eine Modulierung des zentralen Schmerzes durch die STN-THS nicht belegt ist. Eine kürzlich veröffentlichte Arbeit hat jedoch bei Parkinson-Patienten mit Schmerzen demonstriert, dass eine Veränderung der Impulsfrequenz hin zu einer "low-frequency" Stimulation die mechanische Schmerzschwelle verändern kann [60].…”