Spontaneous pain, pain threshold, and pain tolerance in Parkinson’s disease

Abstract

The mechanisms underlying pain in Parkinson's disease (PD) are unclear. Although a few studies have reported that PD patients may have low pain threshold and tolerance, none could accurately assess whether there was a correlation between sensory thresholds and demographic/clinical features of PD patients. Thus, tactile threshold, pain threshold, and pain tolerance to electrical stimuli in the hands and feet were assessed in 106 parkinsonian patients (of whom 66 reported chronic pain) and 51 age- and sex-matched healthy subjects. Linear regression models determined relationships between psychophysical parameters and demographic/clinical features. Female gender, severity of disease, medical disease associated with painful symptoms, and dyskinesia were more frequently observed in PD patients experiencing pain, even though dyskinesia did not reach significance. Pain threshold and pain tolerance were significantly lower in PD patients than in control subjects, whereas the tactile threshold yielded comparable values in both groups. Multivariable linear regression analyses yielded significant inverse correlations of pain threshold and pain tolerance with motor symptom severity and Beck depression inventory. Pain threshold and pain tolerance did not differ between PD patients with and without pain. In the former group, there was no relationship between pain threshold and the intensity/type of pain, and number of painful body parts. These findings suggest that pain threshold and pain tolerance tend to decrease as PD progresses, which can predispose to pain development. Female gender, dyskinesia, medical conditions associated with painful symptoms, and postural abnormalities secondary to rigidity/bradikinesia may contribute to the appearance of spontaneous pain in predisposed subjects.

Non-Motor and Motor Features in LRRK2 Transgenic Mice

“…It is characterized by two different neurological responses towards the pain stimuli: (i) a first phase, starting immediately after injection of formalin, and responding to the local stimulation of nociceptors, and (ii) a second phase occurring later in time and reflecting the response of the central nervous system towards the stimulus, especially the spinal cord. PD patients display chronic unexplained pain and a decrease in pain tolerance [37], [44]. We therefore expected the Tg mice to show an increase of the pain sensitivity following the injection of the formalin in the paw, and in particular in the second phase, which is considered as a chronic response [34].…”

Parkinson's disease related pain: a review of recent findings

“…Currently only indirect evidence suggested nociceptive system dysfunction in patients with PD. The study by Zambito and colleagues [26] adds information on how PD can put patients at higher risk of pain than healthy subjects. Using electrical stimulation they assessed tactile threshold, pain threshold, and pain tolerance in 106 PD patients (66 of whom had chronic pain).…”

Clinical Study on Chronic Pain in Parkinson's Disease Patients in Shanghai, China

“…A major finding of the study was that significant differences with respect to gender, geographic distribution, and age (tables 1, 4) were similar to those reported by Marcus et al [20], who found that pain, fatigue, and psychiatric complaints were more commonly reported in women. Reduced pain thresholds and tolerance [5,19,21] and/or increased responses to pain stimuli were observed in females [22]. Schestatsky et al [19] and Brefel-Courbon et al [11] discovered that during off-periods, patients with PD and central pain had a lower threshold for pain caused by thermal stimuli.…”

“…This controversy might be related to the potential effect of dopamine on pain inhibition pathways. Since at least one of the cortically based descending pain inhibitory pathways is partially dopaminergic (rostral agranular insular cortex) [18], the dopaminergic denervation indicates a higher level of pain and suggests that the causes of pain might be related to movement disorders as well as the loss of dopaminergic neurons in the substantia nigra [18] and arise from central basal ganglia dysfunction [5,19]. Evidence has shown an increased incidence of nondystonic or musculoskeletal pain and pain relief experienced by the patient subsequent to levodopa therapy as well as an increased pain threshold observed during the on-period [19].…”

“…It might be described as vague, poorly located, discomfort, tension, tickling, and burning, and it may precede the motor symptoms of PD, with little response to dopaminergic therapy. Most research on pain in PD has been conducted in Western countries [4,5], and little is known about the prevalence and associated factors of pain among PD patients in China. Therefore, we analyzed the data of PD patients in China to identify the epidemiological characteristics of pain among Chinese patients living in Shanghai because the constitutions and medical conditions of Chinese PD patients are very different from those of individuals of other ethnic groups [6].…”