Marek Kunc

Risk behavior in opioid-dependent individuals after the administration of a therapeutic dose of methadone.

BACKGROUND AND OBJECTIVES Evidence suggests that methadone may play a protective role in the faulty decision-making in heroin-addicted individuals. This may reduce craving for opioids and the risky decisions associated with active opioid use. METHODS We tested the effect of a daily therapeutic dose of methadone on faulty decision-making in eighty (n = 80) individuals with a history of opioid addiction. We used the Iowa Gambling Task (IGT) and compared the score and response time before and after the daily methadone dosing. RESULTS The mean net IGT score before methadone dose was 10 (±22) and 22 (±23) after methadone dose (t = 4.23, p = .00006). These results reflect statistically significant improvement in faulty decisions after the administration of the daily methadone dose. The mean response time for the reward cards before methadone dose were 1,856 ms (±871) and 1,465 ms (±851) after methadone dose (t = 2.55, p = .012). The mean response time for the punishment cards before methadone dose were 1,688 ms (±911) and 1,399 ms (±827) after methadone dose (t = 1.86, p = .065). These results reflect statistically significant improvement in response time to a rewarding healthy decisions after the administration of the daily methadone dose. CONCLUSIONS AND SCIENTIFIC SIGNIFICANCE This is the first study to report the effect of a therapeutic dose of methadone on improving faulty decisions for individuals with a long history of opioids addiction. This study demonstrated that the time to making a healthy decision was significantly shorter as a result of administration of methadone.

Analysis of tremor in motor learning task

Abstract Hand-eye coordination is required in many skilled tasks. Individual differences affect the performance of people at work and leisure, for example, during assembly jobs or sports. The aim of this study was to determine whether motor learning can change the physiological action of hand tremor. Tremor is a repetitive and stereotyped movement, with regular frequency and amplitude, but there are different types of tremors with pattern variation. The results were calculated by participants’ time-on and time-off the target, the average distance from the center of the target, and the frequency of oscillatory movement of a cursor (tremor). The results of this study indicate a statistically significant (p<0.05) influence of effect of task repetition on improvement of motor control and reduction of a high-amplitude tremor and an increase of a low-amplitude tremor. The assessed individuals achieved more than 50% better outcomes of a hand-eye coordination task in the final trials when compared with the initial trials. The dynamics of motor learning tend to rise, with a steady level of a 1-h interval between trials.

Improvement of saccadic functions after dosing with methadone in opioid addicted individuals

ABSTRACT In the current experiment, we used the saccadometric test to study the effect of a single therapeutic dose of methadone on the integrity of cortico-subcortical brain functioning. In this prospective study, we used the Saccadometer System (Advanced Clinical Instrumentation, Cambridge, UK). The saccadometric test was performed before and 1.5 hours after methadone dosing. We analyzed the following saccadic parameters: latency, duration, amplitude, average and peak velocity, and processing performance (promptness) as well as a number of different types of saccades (like correct/incorrect, under/overshoot, and left-sided/right-sided). The sample consists of 40 subjects with an average 18 years of opioid addiction. The mean age is 35.3 ± 7 (80% males and 20% females). The mean period of heroin dependence is 15.3 ± 6.3 years. The mean daily dose of methadone in substitution therapy is 90 ± 26.5 mg. After administration of a single therapeutic dose of methadone, there were statistically significant differences in the values of saccade duration and latency when compared to the values before the drug administration. Average duration of saccade was significantly longer [51.40 ± 8.75 ms versus 48.93 ± 6.91 ms, z = 2.53, p = .01] and average latency was significantly longer [198.85 ± 52.57 ms versus 183.05 ± 30.95 ms, z = 2.09 p < .03]. This is the first study to test the therapeutic effect of daily methadone dosing on the integrity of the cortico-subcortical brain functions as measured by the saccadometry. More research is needed to explore the effect of illicit opioid use on the integrity of brain structures and functions, and the protective effect of opioid agonist therapy on reversing the damaging effects of illicit opioid use.

Prolonged Latency Saccades in Alcohol-dependent Patients

Aims The aim of this study was to assess the differences in saccadic latency (a measure of time delay experienced in eye movements) between alcohol-dependent and healthy controls. Materials and methods Participants Ninety-nine alcohol dependent patients were examined. Thirty-eight healthy controls were matched to the affected cohort according to demographic characteristics. Assessment In this study we used the Saccadometer Advanced System (Advanced Clinical Instrumentation, Cambridge, UK). The Saccadometer System allows quick and easy collection of saccadic responses within the shortest physiologically possible time (100 saccades in 5 min). The brevity of the testing routine minimizes any potential influence on the results due to fatigue in the test subjects. The eye movement measurements are automated and synchronised with stimuli presentation. This study analyzed saccadic latency and standard deviation of mean latency. Results There was higher saccadic latency and standard deviation of mean latency in alcohol-dependent individuals (224.43±56.24 msec) when compared to healthy controls (187.84±25.65 msec). A marked asymmetry of standard deviation of mean latency between right-sided and left-sided saccades was observed in the affected cohort. There was an increased standard deviation of right-sided saccades mean latency (69.96 msec) in alcohol-dependent individuals when compared to healthy controls (30.93 msec) and also an increased standard deviation of left-sided saccades mean latency (59.33 msec) when compared to healthy controls (33.09 msec). Conclusion It was found that alcohol dependence is associated with impaired (longer time delay) saccadic reaction.

Early effect of thalamotomy on cognitive function in patients with Parkinson's disease.

Abstract Thalamotomy is a neurosurgical procedure used in the treatment of advanced Parkinson’s disease (PD). The aim of our research is to evaluate the early impact of a lesion in the ventrointermedial nucleus (VIM) of the thalamus on cognitive and motor function in people with PD. Sixty patients who qualified for right- or left-sided VIM thalamotomy were involved in the study. The cognitive and motor functions of each patient were assessed both prior to and following the surgical procedure. Twenty-nine PD patients without ablative treatment were qualified for the comparison group, and 57 neurologically healthy individuals were assigned to the control group. The following tests were carried out: Mini Mental State Examination, Benton Visual Retention Test, Stroop Color and Word Test, Trail Making Test A&B, and Rey Auditory Verbal Learning Test. Statistically significant differences were found in reaction time, visual-spatial working memory, auditory-verbal memory, and overall level of cognitive function when comparing the results of tests carried out before and after thalamotomy and when comparing patients who had undergone surgery with untreated or healthy individuals. In patients with right-sided and left-sided thalamotomy differences were also found in the mean number of perseverative errors and recalled words.

The Dependence of the Saccadic Refixation Parameters Values From the Time of Substitution Treatment Opioid Addicted Subjects

Introduction The saccadic movements are associated with activation of the certain brain regions. These cerebral areas are responsible also for controlling executive functions. In the current experiment we used an objective test (i.e. saccadometry) to study the effect of a single therapeutic dose of methadone on the integrity of cortico-subcortical brain functioning in individuals with diagnosis of heroin addiction. Aims Assessment the ocular movements (saccades) in opioid addicted subjects in the dependence of the time of substitution treatment. Methods Eighty-eight patients from the substitution program were examined (mean age 39±7.7 years, mean daily dose of methadone: 71.9±(33.4) mg) The study included 55 subjects treated with methadone from one year to three years and subjects treated with methadone from three to seven years. The examination was conducted twice: before and about 1,5 hours after the administration of a therapeutic dose of methadone. Performed Latency Task (LT) with Saccadometr diagnostic system. Results The statistical analysis shows that the mean duration after the administration of methadone in the subjects treated with methadone from one year to three years was statistically significantly increased (p=0,0001) but in the subjects treated with methadone from three to seven years was no statistically significant difference (p=0,0524). No statistically significant differences were found in other parameters of the test. Conclusion The results indicate a change in the dynamics of saccade after methadone administration in subjects treated with methadone from one year to three years compared to the subjects treated with methadone from three to seven years.

Peak Velocity of Saccades in Alcohol-dependent Patients

Aims The aim of this study was to assess the differences in peak velocity of eye movements between alcohol-dependent and healthy controls. Materials and methods Participants Ninety-nine alcohol dependent patients were examined. Patients with oculomotor impairment were excluded. Thirty-eight healthy controls were matched to the affected cohort according to demographic characteristics. Assessment In this study we used the Saccadometer Advanced System (Advanced Clinical Instrumentation, Cambridge, UK). The eye movement measurements are automated and synchronized with stimuli presentation. The person conducting the experiment needs to ensure that the sensor is placed correctly and to give instructions to the test subject. The Saccadometer System does all other measurements and recordings of test data automatically. The study analyzed the peak velocity of eye movements of amplitude of 10 degrees and the deviations in peak velocity. Results There was a statistically significant higher mean peak velocity of saccadic eye movements in alcohol-dependent individuals (440.82±86.33deg/s) when compared to healthy controls (411.39±86.33deg/s). Greater asymmetry of mean peak velocity between right-sided and left-sided saccades was observed in the affected cohort when compared to the healthy test subjects. There was a higher mean right-sided peak velocity (462.73±118.54deg/s) in the alcohol dependent subjects when compared to healthy controls (414.68±73.79deg/s) and also a higher mean of left-sided peak velocity (418.82±79.83deg/s) when compared to healthy controls (405.13±49.50deg/s). Conclusion It was found that alcohol dependence is associated with differences and significant increased asymmetry of peak velocity of eye movements.

Oculomotor disturbances in HIV-positive individuals treated with methadone.

INTRODUCTION Methadone substitution is claimed to be the most effective way of pharmacological management of human immunodeficiency virus (HIV) positive patients addicted to opioids. Possible and clinically the most relevant drug interactions are those between methadone and antiretroviral agents [13,18,25,32]. HIV causes cognitive impairment by infiltrating the central nervous system (CNS) in the initial phase of infection. The consequence of this is damage to the hippocampus, caudate nucleus, and basal ganglia [2,26]. METHODS Eighty-six patients from the substitution program group were examined. The trial was conducted twice: before and about 1.5 hours after the administration of a therapeutic dose of methadone. The antisaccades task (AT) and latency task (LT) were performed using a saccadometer diagnostic system. RESULTS The statistical analysis showed that the mean duration of latency measured by AT in HIV(-) and HIV(+) subjects after the administration of a therapeutic dose of methadone was significantly increased (p=0.03 HIV(-); p=0.04 HIV(+)). There was a statistically significant increase in the mean latency after the administration of methadone in HIV(+) subjects when compared to the control group measured by LT (p=0.03). CONCLUSION The statistical analysis confirms the change in the saccadic refixation parameters in patients addicted to opioids. Methadone influences saccadic dynamic parameters less in HIV(+) than in HIV(-) drug users. Oculomotor disturbances are probably related to the neurotropic effects of HIV leading to damage of the striatum, which plays an important role in psychomotor functions.

EPA-1229 – Comparison of the saccadic refixation parameters in patients treated with methadone and individuals from the control group

Introduction Administration of psychoactive drugs increases dopaminergic receptor stimulation, improves mood and stimulates motor activity. Structural and functional changes can be observed in particular structures of the central nervous system (CNS). Aims/Objectives This study aims to assess the saccadic refixation parameters in opioid addicted subjects treated with methadone compared to control group. Methods Eighty-six patients from the substitution program were examined. The study included 36 subject of the control group. The trial was conducted twice: before and about 1.5 hours after the administration of therapeutic dose of methadone. Performed Latency Test(LT) with Saccadometr diagnostic system. Results The statistical analysis showed that the mean duration before and after the administration of methadone was a statistically significant increases (p=0,0001) in the subjects from substitution program compared of the control group but after administration of methadone the value greatly increased in experimental group (before 52 ms , after 56 ms ). It was observed that the mean amplitude after the administration of methadone increased statistically significantly in experimental group compared of the control group (p=0,02). Mean peak velocity of latency after the administration of a therapeutic dose of methadone was statistically significant decreased in experimental group compared of the control group (p=0,0004). Conclusion The results indicate a change in the dynamics of saccade after methadone administration. The observed changes in values for eye movements may be due to the inhibitory effect of methadone on CNS.

Computer-based system to capture, collect, process and analyze data in psychomotor tests

Abstract The article explains the principles and goals in creating a computer-based system for the measurement of psychomotor functioning, its functionality, and user interface. To illustrate the capabilities of the system, the results of analysis of the selected psychomotor tests performed in different groups of patients are presented. The usefulness of the presented tool in the quantitative study of psychomotor functioning is assessed.