Sensory neuropathic symptoms in idiopathic Parkinson's disease: prevalence and impact on quality of life

BACKGROUND

Neuropathic symptoms are commonly reported in Parkinson's disease (PD), but robust data on the epidemiology of such symptoms are lacking. The present study sought to investigate the prevalence and determinants of peripheral sensory neuropathic symptoms (PSNS) in idiopathic PD (IPD) and ascertain the effects of such symptoms on the patients' quality of life (QoL).

METHODS

Patients with IPD and age-matched and gender-matched controls were screened for neuropathic symptoms using the Michigan Neuropathy Screening Instrument. The impact of neuropathic symptoms on QoL was investigated using the 36-Item Short Form Survey.

RESULTS

Fifty-two patients and 52 age-matched and gender-matched controls were recruited. PSNS were reported more frequently in patients with IPD than in the control subjects (57.7 versus 28.8%, p = 0.003). No significant relationships were found between PD-related clinical characteristics (i.e. disease severity and duration, duration of exposure to levodopa) and the presence of PSNS. Significant correlations were found between the number of PSNS and physical functioning (Spearman's Rho - 0.351), even after adjusting for age, gender and Hoehn and Yahr score.

CONCLUSION

Our results support the notion of a greater prevalence of PSNS in IPD patients as compared to the general population, which, at least in part, may be secondary to large and/or small fibre peripheral neuropathy. This warrants further investigation in larger studies that include detailed neurophysiological assessments.

Effect of α-lipoic acid on symptoms and quality of life in patients with painful diabetic neuropathy

Objective

To examine the effect of α-lipoic acid on neuropathic symptoms in patients with diabetic neuropathy (DN).

Methods

Patients with painful DN were treated with 600 mg/day α-lipoic acid, orally, for 40 days. Neuropathy Symptom Score (NSS), Subjective Peripheral Neuropathy Screen Questionnaire (SPNSQ) and douleur neuropathique (DN)4 questionnaire scores were assessed at baseline and day 40. Quality-of-life treatment effects were assessed by Brief Pain Inventory (BPI), Neuropathic Pain Symptom Inventory (NPSI) and Sheehan Disability Scale (SDS). Changes in body weight, arterial blood pressure, fasting serum glucose and lipids were also assessed.

Results

Out of 72 patients included, significant reductions in neuropathic symptoms were shown by reduced NSS, SPNSQ and DN4 scores at day 40 versus baseline. BPI, NPSI, and SDS in terms of work disability, social life disability, and family life disability scores were also significantly reduced. Moreover, 50% of patients rated their health condition as ‘very much better’ or ‘much better’ following α-lipoic acid administration. Fasting triglyceride levels were reduced, but no difference was found in body weight, blood pressure, fasting glucose, or other lipids at day 40 versus baseline.

Conclusions

A-lipoic acid administration was associated with reduced neuropathic symptoms and triglycerides, and improved quality of life.

Predictors of response to treatment with actovegin for 6 months in patients with type 2 diabetes and symptomatic polyneuropathy

AIMS

To evaluate two definitions of response and the predictive value of baseline covariates for response to actovegin treatment in type 2 diabetic patients with symptomatic diabetic sensorimotor polyneuropathy (DSPN).

METHODS

Response to 6-months treatment with actovegin or placebo was defined as a clinically meaningful decline from baseline to 6months in (1) both Neuropathy Impairment Score of Lower Limbs (NIS-LL) ≥2 points and Total Symptom Score (TSS) >50% and (2) NIS-LL ≥2 points only. Nineteen baseline covariates were evaluated using separate logistic regression models and either both NIS-LL and TSS or NIS-LL response definitions.

RESULTS

Intention-to-treat analysis included 567 patients. Actovegin treatment compared to placebo was associated with better odds of response (OR [95% CI] of 1.73 [1.21-2.48] for definition 1 and 1.94 [1.33-2.84] for definition 2). Significant interaction with actovegin treatment was noted only for baseline use of angiotensin receptor blockers (ARBs)/angiotensinogen converting enzyme inhibitors (ACEIs), resulting in a reduced treatment response (P=0.03).

CONCLUSIONS

Actovegin treatment was associated with a clinically meaningful response in neuropathic symptoms and/or impairments in patients with symptomatic DSPN. Since only one predictor of response to actovegin treatment was identified, this drug seems an appropriate therapy for the majority of patients with DSPN.