Combined EEG and immersive virtual reality unveil dopaminergic modulation of error monitoring in Parkinson's Disease.

Detecting errors in your own and others' actions is associated with discrepancies between intended and expected outcomes. The processing of salient events is associated with dopamine release, the balance of which is altered in Parkinson's disease (PD). Errors in observed actions trigger various electrocortical indices (e.g. mid-frontal theta, error-related delta, and error positivity [oPe]). However, the impact of dopamine depletion to observed errors in the same individual remains unclear. Healthy controls (HCs) and PD patients observed ecological reach-to-grasp-a-glass actions performed by a virtual arm from a first-person perspective. PD patients were tested under their dopaminergic medication (on-condition) and after dopaminergic withdrawal (off-condition). Analyses of oPe, delta, and theta-power increases indicate that while the formers were elicited after incorrect vs. correct actions in all groups, the latter were observed in on-condition but altered in off-condition PD. Therefore, different EEG error signatures may index the activity of distinct mechanisms, and error-related theta power is selectively modulated by dopamine depletion. Our findings may facilitate discovering dopamine-related biomarkers for error-monitoring dysfunctions that may have crucial theoretical and clinical implications.

Predicting the fate of basketball throws: an EEG study on expert action prediction in wheelchair basketball players.

The ability to anticipate and detect changes in human movement helps people to modify their behaviors in ever changing environments. Studies indicate that expertise modulates observation of domain-specific actions in sports-a process that is crucial for adapting rapidly to a new situation, often before awareness of environmental changes is achieved. Here, we explored the electrophysiological underpinnings of wheelchair basketball players predicting the fate of free throws performed by wheelchair basketball athletes. We performed electroencephalography (EEG) in semi-professional wheelchair players with different degrees of expertise (players) and in ambulant, non-expert people (controls) while they observed movie stimuli of a free throw that could land inside or outside the basket. On each trial, participants were asked to predict the outcome of the throw. For each group, event-related potentials (ERPs) were averaged as a function of condition, using only the trials that were correctly predicted. Results show that compared to controls, expert players exhibit a greater negative amplitude of oCNV over Pz (an observational contingent negative variation-like waveform which is considered a marker of action effect prediction) during the wrist movement preceding the ball release (the last 100 ms of the shot), which carries the most crucial kinematic information regarding the fate of the throw. Our data provide further support to the view that functional modulation of the action observation network is associated with expertise.

Comparison of cervical spine motion during intubation with a C­MAC D­Blade® and an LMA Fastrach®.

BACKGROUND: This prospective randomized study compared cervical motion during intubation with a C­MAC D­Blade® and with a laryngeal mask airway LMA Fastrach®. MATERIAL AND METHODS: The participants in this study were 52 ASA I-III patients aged 18-70 years and assigned for elective cervical discectomy. The patients were randomly selected for intubation with a C­MAC D­Blade® (group V) or an LMA Fastrach® laryngeal airway (group F). Both groups received the same induction of anaesthesia. The first lateral view was X­rayed while the head and neck were in a neutral supine position and the second exposure was taken during the passage of the endotracheal tube through the vocal cords for group V and during the advance of the endotracheal tube for group F. The occiput-C1 (C0-C1), C1-C2 and C2-5 angles were measured. The angle formed by the line between the occipital protuberance and anterior process of the foramen magnum and the line between the central point of C1 spinous process and the anterior process of the foramen magnum was defined as angle A. The differences between the angles were calculated. Overall intubation success and first-pass success (success at the first attempt) were recorded. RESULTS: The change in angulations between C0-C1 during intubation was significantly lower in group F than in group V (2.780 ± 2.10 vs. 6.040 ± 4.10, p = 0.007). Before intubation, angle A was 14.40 ± 3.90 in group V and 13.80 ± 3.70 in group F (p = 0.627). During intubation, angle A was significantly smaller for group V than for group F (9.10 ± 2.40 vs. 10.70 ± 2.90, p = 0.04). The number of successful intubations were significantly higher in group V (100% of intubations were successful on the first attempt for group V, vs. 80% for group F, p = 0.023). CONCLUSION: Intubation with both a C­MAC D­Blade and a Fastrach LMA resulted in cervical motion but within safe ranges. Intubation with a C-mac D blade might be preferred because the Fastrach LMA may result in more failed intubation attempts in patients with cervical spine disorders.

Ultrasound-guided pulsed radiofrequency treatment of the pudendal nerve in chronic pelvic pain.

Chronic pelvic pain is a condition that can be caused by pudendal neuralgia, interstitial cystitis, piriformis syndrome and neuropathy of the ilioinguinal, iliohypogastric and genitofemoral nerves. Based on three case reports this article discusses the clinical effectiveness of pulsed high-frequency radiofrequency (PRF) treatment applied to the pudendal nerve under ultrasound guidance in medicinally treated patients with chronic pelvic pain.

Effect of ultrasound-guided intercostal nerve block on postoperative pain after percutaneous nephrolithotomy : prospective randomized controlled study.

BACKGROUND: The aim of the study was to investigate the effect of preoperative ultrasound-guided (US) intercostal nerve block (ICNB) in the 11th and 12th intercostal spaces on postoperative pain control and tramadol consumption in patients undergoing percutaneous nephrolithotomy (PCNL). METHODS: After obtaining ethical committee approval and written informed patient consent, 40 patients were randomly allocated to the ICNB group or the control group. For the ICNB group US-guided ICNB was performed with 0.5 % bupivacaine and 1/200,000 epinephrine at the 11th and 12th intercostal spaces after premedication. A sham block was performed for the control group and postoperative pain and tramadol consumption were recorded by anesthesiologists blinded to the treatment. RESULTS: Postoperative visual analog scale scores at all follow-up times were found to be significantly lower in the ICNB group than in the control group (p < 0.05). The mean 24 h intravenous tramadol consumption was 97.5 ± 39.5 mg for the ICNB group which was significantly lower than the 199.7 ± 77.6 mg recorded for the control group (p < 0.05). CONCLUSION: In PCNL with nephrostomy tube placement US-guided ICNB performed at the 11th and 12th intercostal spaces provided effective analgesia.

Propofol sedation in total knee replacement : effects on oxidative stress and ischemia-reperfusion damage.

PURPOSE: This study aimed to show the effect of propofol sedation on oxidative stress and inflammation resulting from ischemia-reperfusion. METHODS: After having obtained written informed consent from the patients and ethics committee approval, 36 patients were randomly allocated to 2 groups: group C, control and group P, propofol. Spinal anesthesia was administered to both groups with 15 mg bupivacaine. Patients in group P received a propofol infusion of 2 mg/kgBW/h and the patients in group C received a placebo infusion in an equal dose. Malondialdehyde (MDA), superoxide dismutase (SOD) and the total antioxidative capacity (TAC) levels were measured in venous blood samples prior to propofol or placebo administration (preischemia T0), 30 min after placing the tourniquet (ischemia T1) and 2 h after deflation of the tourniquet (reperfusion T2). High sensitivity C-reactive protein (hsCRP) and neutrophil levels were measured before propofol was administered (T0) and 12 h after reperfusion (T3). RESULTS: While serum MDA and SOD levels were significantly higher during the reperfusion period than the preischemic period, TAC levels were found to be low in the control group (p < 0.05). In the propofol group there were no differences between the preischemia-reperfusion periods with respect to MDA, SOD and TAC levels (p > 0.05). The neutrophil and hsCRP levels were observed to be increased to a lesser extent in the propofol group compared to the control group (p < 0.05). CONCLUSIONS: Propofol infusion in addition to spinal anesthesia may reduce oxidative damage and the inflammatory response developing due to the tourniquet in total knee replacement surgery.

The effects of tramadol infiltration on wound healing in rats.

PURPOSE: Infiltration of a local anesthetic to provide postoperative analgesia is a frequently used method. However the infiltrated agents may have negative effects on wound healing. This study aimed to investigate the effects of tramadol, a weak opioid with a local anesthetic effect, on wound healing. METHODS: Wistar albino rats were used in the study. Tramadol and saline infiltration was randomly performed on the left and right backs of rats. Following a linear incision, the site was sutured. A follow-up was conducted after seven days, and the tissue samples from both locations were extracted for histopathological examinations (fibrotic index : no fibrosis 0, mild 1, moderate 2, severe 3) and hydroxyproline measurements. RESULTS: The hydroxyproline level found in the tramadol group was 0.060 +/- 0.04 ng/mg.protein. In the control group the hydroxyproline level was 0.012 +/-0.01 ng/mg.protein (p = 0.01). The fibrotic index levels in the tramadol group were higher than the control group (p < 0.001). CONCLUSION: It was concluded that tramadol infiltration in a surgical incision site has no adverse effect on wound healing.

The effects of supplementation with a mixture of arginine, glutamine, and beta-hydroxy beta-methylbutyrate on the healing of colon anastomoses.

BACKGROUND: Several researchers have investigated how wound healing is effected by supplementation with each of the following amino acids : arginine (Arg), glutamine (Glu), and beta-hydroxy beta-methylbutyrate (HMB). This research investigates how a combination of these amino acids improves the wound healing associated with anastomoses. METHODS: We tested the effects of a combination of Arg, Glu, and HMB on the healing of colon anastomoses in 50 male rats. We randomly divided the animals into two equal groups. In each animal, the cecum was transected from its midpoint to create an end-to end anastomosis. During the first postoperative week, Group 1 (G1) animals were fed standard chow, and Group 2 (G2) animals were fed standard chow plus a ready-to-use supplement that contained a mixture of Arg, Glu, and HMB. At the end of the week, all of the rats were sacrificed, and a cecum segment containing the anastomosis line was resected. Bursting pressure and tissue hydroxyproline were measured for all animals. RESULTS: The mean values for hydroxyproline were 0.0013 ng/mg protein/ml (SD +/-0.00075) and 0.034 ng/mg protein/ ml (SD +/- 0.022) for G1 and G2, respectively (p <0.0001). The mean values for bursting pressure measurements were 122.8 mmHg (SD +/- 9.4) and 192.8 mmHg (SD+/- 31) for G1 and G2, respectively (p <0.0001). Statistically significant differences between the groups in terms of both bursting pressure levels and tissue hydroxyproline levels were observed. CONCLUSION: In an animal model of colon surgery, supplementation with a combination of three amino acids seemingly benefits anastomosis healing.

Effect of magnesium sulphate on bleeding during lumbar discectomy.

We assessed the effect of magnesium on the amount of bleeding, coagulation profiles and surgical conditions during lumbar discectomy under general anaesthesia. Forty patients, of ASA physical status 1-2 and aged 18-65 years, undergoing single-level microscopic lumbar discectomy, were randomly assigned to magnesium sulphate (50 mg.kg(-1) in 100 ml saline over 10 min followed by a continuous infusion of 20 mg.kg.h(-1) ) or saline. The mean (SD) estimated blood loss was 190 (95) and 362 (170) ml in the magnesium and saline groups, respectively (mean difference = 172 ml; 95% CI 84-260 ml). The median (IQR [range]) Fromme's scale score for surgical conditions for the magnesium and saline groups were 2 (2-3 [2-3]) and 3 (2-3 [3-4]), respectively (p < 0.05). The bleeding time, haemoglobin, platelet count, prothrombin time, international normalised ratio and fibrinogen levels were similar in the two groups. The activated partial thromboplastin time was prolonged in the magnesium group immediately postoperatively and at 6 h after surgery. After the bolus of magnesium, the heart rate was higher and the mean arterial pressure lower in the magnesium group. The use of magnesium sulphate during lumbar discectomy decreases blood loss, and provides better surgical conditions without marked haemodynamic effects.

Functional recovery of patients with brain tumor or acute stroke after rehabilitation: a comparative study.

The aim of this study was to compare the locomotor functional recovery of patients with brain tumor and patients with stroke. Each patient with a brain tumor was matched to a patient with stroke according to the lesion side. Twenty-one patients operated for intracranial tumors and 21 patients with stroke were studied. The mean ages (+/- standard deviation) of patients were 52.5+/-16 years for patients with brain tumor and 56.7+/-11 years for patients with stroke. For each patient, the age, gender, presence of aphasia, smoking habit, co-morbidities, lesion origin and lesion size (for the brain tumor group) were recorded. Locomotor and functional recovery were evaluated by using the Postural Assessment Scale for Stroke, the Berg Balance Scale, Motor Assessment Scale and the mobility section of the Functional Impairment Measure. There was no difference regarding demographic characteristics between the two groups. After rehabilitation both groups had significantly improved in terms of all parameters, but the extent of improvement did not differ between the two groups.

Determination of the effect of a single hemodialysis session on retrobulbar blood hemodynamics by color Doppler ultrasonography.

BACKGROUND: Retrobulbar hemodynamic alterations can occur during hemodialysis sessions, and patients with chronic renal failure may experience visual problems. PURPOSE: To evaluate the effect of single-session hemodialysis on retrobulbar vessel hemodynamics by color Doppler ultrasonography. MATERIAL AND METHODS: Thirty-five patients were included in the study. Retrobulbar blood flows were examined before and after dialysis sessions. Doppler spectral patterns of retrobulbar blood flow were evaluated. The t test for paired samples and the Wilcoxon matched-pairs signed-rank test were used for comparing the flow values before and after dialysis. RESULTS: Systolic and diastolic blood flow velocities of the ophthalmic artery, central retinal artery, central retinal vein, nasal posterior ciliary artery, and temporal posterior ciliary artery were found to be decreased bilaterally after hemodialysis sessions. No significant change was observed in resistivity index values after hemodialysis sessions. CONCLUSION: Our findings reveal that retrobulbar circulation was disturbed after a single hemodialysis session.