The effect of a 9-month hybrid intradialytic exercise training program on nerve conduction velocity parameters in patients receiving hemodialysis therapy.

INTRODUCTION AND AIMS: Neurological complications such as peripheral neuropathy are very common in the end-stage renal disease (ESRD) patients, occurring in 60-80% of this specific population. The aim of the present study was to examine whether a 9-month hybrid intradialytic exercise training program could alter motor and sensory nerve conduction study (NCS) parameters in hemodialysis population. METHODS: Seventeen stable patients undergoing HD with no clinical evidence of uremic polyneuropathy were included in the study (15 M/2F, 59 ± 13.7 years). All patients completed a 9-month supervised exercise training program composed of both aerobic cycling and resistance training (hybrid) during HD. Functional capacity was assessed by a battery of tests, while pain levels and fatigue profile were assessed via validated questionnaires. Motor and sensory NCS on bilateral median, ulnar, peroneal and tibial nerves as well as F-wave were assessed using a full neurographic electromyography (EMG) assessment. RESULTS: After the 9-month exercise training intervention, exercise capacity was increased by 65% and functional capacity by an average of 40%. The neurological assessment showed that conduction velocity from tibial and peroneal nerves was improved by 3.7% and 4.2%, respectively, while tibial F-wave latency and peroneal and sural nerve distal latency were significantly improved by 4.2%, 4.9% and 10%, respectively. Fatigue and pain were improved after the exercise intervention while fatigue score was positively correlated with conduction velocity and amplitude values. CONCLUSIONS: The results of the current study demonstrate that 9-month hybrid exercise training induces beneficial effects on both sensory and motor NCS parameters, improving conduction velocity and F-wave latency. Improvements in neural activity were accompanied by changes in fatigue score and pain-related aspects. The parallel improvement in motor nerve conduction velocity and its correlations with functional tests supports the hypothesis that exercise could be beneficial for preventing a decline in neural function in HD patients.

Cardiac autonomic function during intradialytic exercise training.

Objectives: Cardiac autonomic nervous system (ANS) dysfunction is a common feature in patients receiving hemodialysis (HD) therapy, whilst is associated with an increased risk of ventricular arrhythmias and sudden cardiac death. The aim of this study is to investigate and compare the hemodynamic changes and responses of ANS function in HD patients using pupillometry and Heart Rate Variability (HRV) parameters. Methods: Sixteen chronic kidney diseases (CKD) patients receiving HD (52.18 ± 17.7 years) underwent both pupillometric measurements using a portable handheld pupil-measuring device and standard HRV analysis pre HD, every hour and 30 min post-HD session under two different scenarios: at rest while the patient resting at HD bed and when the patient performed a single bout of intradialytic aerobic exercise lasting for 45 min during the second hour of the HD therapy. Results: No significant changes in ANS values were observed in neither of the pupillometric and the HRV values pre HD, for each hour and post-HD session. HRV parameters were significantly correlated with pupillometric parameters at pre HD and immediately after the single bout of intradialytic exercise. ANS activity did not differ during the conventional HD session and during the session included intradialytic exercise. Moreover, sympatho-vagal balance indices deriving from pupillometric assessment showed beneficial changes after the exercise event. Conclusion: Pupillometry is a promising and robust technique with fewer artifacts compared to HRV especially in studies involving exercise sessions. Thus, pupillometry can be used as a complementary tool in the evaluation of cardiac autonomic dysfunction.

Perimetric and retinal nerve fiber layer findings in patients with Parkinson's disease.

BACKGROUND: Visual dysfunction is common in Parkinson's disease (PD). It remains, however, unknown whether it is related to structural alterations of the retina. The aim of this study is to compare visual field (VF) findings and circumpapillary retinal nerve fiber layer (RNFL) thickness in a series of PD patients and normal controls, in order to assess possible retinal anatomical changes and/or functional damage associated with PD. METHODS: PD patients and controls were recruited and underwent VF testing with static automated perimetry and RNFL examination with optical coherence tomography (OCT). Cognitive performance using Mini Mental State Examination (MMSE), PD staging using modified Hoehn and Yahr (H-Y) scale and duration of the disease was recorded in PD patients. RESULTS: One randomly selected eye from each of 24 patients and 24 age-matched controls was included. OCT RNFL thickness analysis revealed no difference in the inferior, superior, nasal or temporal sectors between the groups. The average peripapillary RNFL was also similar in the two groups. However, perimetric indices of generalized sensitivity loss (mean deviation) and localized scotomas (pattern standard deviation) were worse in patients with PD compared to controls (p < 0.01). 73% of eyes of PD patients had glaucomatous-like asymmetrical hemifield defects with abnormal Glaucoma Hemifield Test and various combinations of arcuate defects (n = 12), nasal steps (n = 11) and paracentral scotomas (n = 16). Bilateral defects were found in 14 patients (58%). No correlation was found between VF indices and MMSE or H-Y scores. CONCLUSION: PD patients may demonstrate glaucomatous-like perimetric defects even in the absence of decreased RNFL thickness.

Evidence of an association between the scavenger receptor class B member 2 gene and Parkinson's disease.

Lysosomal protein 2 (LIMP2), the product of the scavenger receptor class B member 2 (SCARB2) gene, is a ubiquitously expressed transmembrane protein that is the mannose-6-phosphate-independent receptor for glucocerebrosidase (ß-GCase); a deficiency in this protein causes Gaucher disease. Several studies have shown a link between mutations in the ß-GCase gene and diseases characterized clinically by Parkinsonism and by the presence of Lewy body-related pathology. We hypothesized that genetic variants in the SCARB2 gene could be risk factors for Parkinson's disease (PD). A candidate-gene study of 347 Greek patients with sporadic PD and 329 healthy controls was conducted to investigate the association between 5 polymorphisms in the SCARB2 gene (rs6824953, rs6825004, rs4241591, rs9991821, and rs17234715) and the development of PD. The single-locus analysis for the 5 polymorphisms revealed an association only for the rs6825004 polymorphism: the generalized odds ratio (OR(G) ) was 0.68 (95% confidence interval [CI], 0.51-0.90), and the OR for the allelic test was OR = 0.71 (95% CI, 0.56-0.90). Haplotype analysis showed an association for the GCGGT haplotype (P < .01). Our study supports a genetic contribution of the SCARB2 locus to PD; future studies in larger cohorts are necessary to verify this finding.

Non-pharmacological management of periodic limb movements during hemodialysis session in patients with uremic restless legs syndrome.

Restless legs syndrome (RLS) is very common in hemodialysis patients. RLS induces motor excitability and discomfort during rest periods, and those symptoms have also been observed during hemodialysis sessions. The aim of the study was to assess whether a single bout of exercise could reduce periodic limb movements (PLM) occurring during hemodialysis. Eighteen hemodialysis patients were eligible and participated in the study. Using the RLS criteria and further verified by the presence of PLM during sleep, patients were divided to non-RLS and RLS groups. Three scenarios were studied during three different sessions: 1) light exercise, including cycling for 45 minutes with no added resistance, 2) heavy exercise, including cycling for 45 minutes with a resistance set at 60% of their exercise capacity, and 3) no exercise, including rest for the same period of time. In all sessions, PLM per hour of hemodialysis (PLM/hHD) was recorded. A single bout of either light or heavy exercise was equally effective in significantly reducing PLM/hHD in patients with RLS compared with the no-exercise scenario, whereas in non-RLS patients, no effect was observed. Independent of intensity, a single bout of intradialytic exercise reduces PLM/hHD in hemodialysis patients with RLS. Further research is needed to establish the acute role of exercise in ameliorating the RLS symptoms.

Cerebral venous sinus thrombosis: review of the demographics, pathophysiology, current diagnosis, and treatment.

Cerebral venous sinus thrombosis (CVST) is a rare clinicopathological entity. The incidence of CVST in children and neonates has been reported to be as high as 7 cases per million people, whereas in adults the incidence is 3-4 cases per million. The predisposing factors to this condition are mainly genetic and acquired prothrombotic states and infection. The clinical picture of CVST is nonspecific, highly variable, and can mimic several other clinical conditions. Diagnosis of CVST is established with the implementation of neuroimaging studies, especially MR imaging and venography. Identification and elimination of the underlying cause, anticoagulation, proper management of intracranial hypertension, and anticonvulsant prophylaxis constitute cornerstones of CVST treatment. Newer treatment strategies such as endovascular thrombolysis and decompressive craniectomy have been recently used in the treatment of patients with CVST with variable success rates. Further clinical research must be performed to delineate the exact role of these newer treatments in the management of severe cases of CVST. The recent advances in the diagnosis and treatment of patients with CVST have significantly lowered the associated mortality and morbidity and have improved the outcome of these patients.