- Email: [email protected]
The influence of rate of stimulation and pulse duration on efficacy of deep brain stimulation for Essential Tremor
Abstracts / Brain Stimulation 8 (2015) 326e342
stimulator with high-voltage tolerance in a 0.18mm 1.8V/3.3V CMOS process, three 3.3V PMOS and three 3.3V NMOS transistors are utilized in this work. Although the operating voltage may be up to 10V, the high-voltage-tolerant stimulator fabricated in the 0.18mm 1.8V/3.3V CMOS process can be safely used. To be able to deliver biphasic stimulation current to the brain tissue, the stimulator uses an H-bridge at its output. The fabricated chip of the electrical stimulator has been integrated into a closed-loop epileptic seizure monitoring and controlling system for animal tests. After stimulation, the intensive and rapidly brain activity in Long-Evans rat with epileptic seizure is suppressed. According to the animal test results, the functionalities of the highvoltage-tolerant stimulator have been successfully verified. Acknowledgment: This work was supported by Ministry of Science and Technology, Taiwan, under Contract MOST 103-2220-E009-007 and MOST 103-2220-E-003-001, and by Biomedical Electronics Translational Research Center, National Chiao Tung University, Taiwan.
80 Effects of Anodal Transcranial Direct Current Stimulation on Working and Recognition Memory: A Systematic Review and Meta-Analysis of Findings from Healthy and Neuropsychiatric Populations Aron T. Hill , Paul B. Fitzgerald , Kate E. Hoy Monash Alfred Psychiatry Research Centre Working and recognition memory systems are vital for a range of cognitive activities and are also frequently impaired in neuropsychiatric disorders. Determining the efficacy with which anodal tDCS (a-tDCS) can modulate these systems is important for both progressing the understanding of cognitive function and also improving the therapeutic potential of this technology. This systematic review and meta-analysis aimed to provide a quantitative synthesis of the published literature investigating the effects of atDCS, compared to sham, on these memory systems. A secondary aim was to better determine optimal parameters for a-tDCS administration. Systematic literature searches yielded a total of 21 studies satisfying inclusion criteria. The pooled results from these experiments demonstrated small improvements in working memory accuracy (SMD ¼ 0.18, CI ¼ 0.06, 0.30, p ¼ 0.004) and reaction time (SMD ¼ -0.16, 95% CI ¼ -0.28, -0.04, p ¼ 0.007). Subgroup analyses indicated that these results were significant for healthy cohorts (Accuracy: SMD ¼ 0.16, CI ¼ 0.02, 0.30, p ¼ 0.02; Reaction time: SMD ¼ -0.17, 95% CI ¼ -0.30, -0.03, p ¼ 0.01), with neuropsychiatric cohorts showing a trend towards significance for accuracy only (SMD ¼ 0.22, CI ¼ -0.01, 0.46, p ¼ 0.07). Additionally, significant small-to-moderate improvements in recognition memory were seen overall (SMD ¼ 0.44, CI ¼ 0.19, 0.68, p ¼ 0.0005) and at the subgroup level for both healthy (SMD ¼ 0.36, CI ¼ 0.06, 0.66, p ¼ 0.02) and neuropsychiatric (SMD ¼ 0.58, CI ¼ 0.16, 1.01, p ¼ 0.007) cohorts. Finally, there was some evidence to suggest that higher current densities and longer stimulation durations were favourable for enhancing working memory performance. Overall, this meta-analytical review demonstrates a varying degree of efficacy for the use of a-tDCS for enhancing memory function. Research is now needed to optimise the proficiency of this technology.
331
b
University of Melbourne, Australia St. Vincent’s Hospital Melbourne, Australia *E-mail: [email protected].
c
Deep brain stimulation (DBS) is used to alleviate tremor in patients diagnosed with Essential Tremor who do not respond to conventional treatments. To achieve optimal tremor suppression, a large stimulus parameter space needs to be explored. In practice, a default pulse duration and stimulation rate (generally 60 us and 130 Hz) are often chosen and current or voltage varied to determine a clinically effective setting. This study explored the effect of rate of stimulation in 5 patients with bilateral DBS stimulation to the posterior sub-thalamic area (PSA). Additionally the effects of varying charge per pulse by varying pulse duration alone or by varying current/voltage alone were compared. In experiment 1, rate was varied using the values 20, 70, 100, 130, 150, and 210 Hz, keeping pulse duration (90 us) and current (1patient) or voltage (4 patients) fixed. In experiment 2, rate was fixed at 130 Hz, and charge per phase was varied first by changing pulse duration between 60, 90, and 120 us, and secondly by altering current or voltage by the same ratios. Tremor severity was categorized by two experienced clinicians. Figure 1 shows the effect of rate for each subject. A repeatedmeasures ANOVA showed a significant effect of rate (p < 0.001) with the 40 Hz rate producing worse tremor scores than all rates of 100 Hz and above. Two patients showed a U-shaped response with best tremor suppression between 100 and 130 Hz, whereas the remaining patients showed a trend for better tremor suppression as rate increased across the whole range. Paired t-tests showed no significant difference between changing charge per phase via pulse duration or current/voltage, although both these effects were small, leading to poor statistical power.
Fig.1 Results of experiment 1. Funding: Colonial Foundation, program, NHMRC.
Victorian
government
OIS
82 81 The influence of rate of stimulation and pulse duration on efficacy of deep brain stimulation for Essential Tremor C.M. McKay a,b,*, H.J. McDermott a,b, T. Perera a, R. Peppard c, M. Jones c, A.P. Vogel a,b a Bionics Institute, Australia
Navigated repetitive transcranial magnetic stimulation in stroke rehabilitation (randomize double-blind sham-controlled study) A.V. Chervyakov , A.G. Poydasheva , M.A. Nazarova , E.A. Zmeykina , N.A. Suponeva , V.V. Gnezditsky , L.A. Chernikova , M.A. Piradov Research Center of neurology Russian academy of medical sciences, Moscow, Russia
stimulator with high-voltage tolerance in a 0.18mm 1.8V/3.3V CMOS process, three 3.3V PMOS and three 3.3V NMOS transistors are utilized in this work. Although the operating voltage may be up to 10V, the high-voltage-tolerant stimulator fabricated in the 0.18mm 1.8V/3.3V CMOS process can be safely used. To be able to deliver biphasic stimulation current to the brain tissue, the stimulator uses an H-bridge at its output. The fabricated chip of the electrical stimulator has been integrated into a closed-loop epileptic seizure monitoring and controlling system for animal tests. After stimulation, the intensive and rapidly brain activity in Long-Evans rat with epileptic seizure is suppressed. According to the animal test results, the functionalities of the highvoltage-tolerant stimulator have been successfully verified. Acknowledgment: This work was supported by Ministry of Science and Technology, Taiwan, under Contract MOST 103-2220-E009-007 and MOST 103-2220-E-003-001, and by Biomedical Electronics Translational Research Center, National Chiao Tung University, Taiwan.
80 Effects of Anodal Transcranial Direct Current Stimulation on Working and Recognition Memory: A Systematic Review and Meta-Analysis of Findings from Healthy and Neuropsychiatric Populations Aron T. Hill , Paul B. Fitzgerald , Kate E. Hoy Monash Alfred Psychiatry Research Centre Working and recognition memory systems are vital for a range of cognitive activities and are also frequently impaired in neuropsychiatric disorders. Determining the efficacy with which anodal tDCS (a-tDCS) can modulate these systems is important for both progressing the understanding of cognitive function and also improving the therapeutic potential of this technology. This systematic review and meta-analysis aimed to provide a quantitative synthesis of the published literature investigating the effects of atDCS, compared to sham, on these memory systems. A secondary aim was to better determine optimal parameters for a-tDCS administration. Systematic literature searches yielded a total of 21 studies satisfying inclusion criteria. The pooled results from these experiments demonstrated small improvements in working memory accuracy (SMD ¼ 0.18, CI ¼ 0.06, 0.30, p ¼ 0.004) and reaction time (SMD ¼ -0.16, 95% CI ¼ -0.28, -0.04, p ¼ 0.007). Subgroup analyses indicated that these results were significant for healthy cohorts (Accuracy: SMD ¼ 0.16, CI ¼ 0.02, 0.30, p ¼ 0.02; Reaction time: SMD ¼ -0.17, 95% CI ¼ -0.30, -0.03, p ¼ 0.01), with neuropsychiatric cohorts showing a trend towards significance for accuracy only (SMD ¼ 0.22, CI ¼ -0.01, 0.46, p ¼ 0.07). Additionally, significant small-to-moderate improvements in recognition memory were seen overall (SMD ¼ 0.44, CI ¼ 0.19, 0.68, p ¼ 0.0005) and at the subgroup level for both healthy (SMD ¼ 0.36, CI ¼ 0.06, 0.66, p ¼ 0.02) and neuropsychiatric (SMD ¼ 0.58, CI ¼ 0.16, 1.01, p ¼ 0.007) cohorts. Finally, there was some evidence to suggest that higher current densities and longer stimulation durations were favourable for enhancing working memory performance. Overall, this meta-analytical review demonstrates a varying degree of efficacy for the use of a-tDCS for enhancing memory function. Research is now needed to optimise the proficiency of this technology.
331
b
University of Melbourne, Australia St. Vincent’s Hospital Melbourne, Australia *E-mail: [email protected].
c
Deep brain stimulation (DBS) is used to alleviate tremor in patients diagnosed with Essential Tremor who do not respond to conventional treatments. To achieve optimal tremor suppression, a large stimulus parameter space needs to be explored. In practice, a default pulse duration and stimulation rate (generally 60 us and 130 Hz) are often chosen and current or voltage varied to determine a clinically effective setting. This study explored the effect of rate of stimulation in 5 patients with bilateral DBS stimulation to the posterior sub-thalamic area (PSA). Additionally the effects of varying charge per pulse by varying pulse duration alone or by varying current/voltage alone were compared. In experiment 1, rate was varied using the values 20, 70, 100, 130, 150, and 210 Hz, keeping pulse duration (90 us) and current (1patient) or voltage (4 patients) fixed. In experiment 2, rate was fixed at 130 Hz, and charge per phase was varied first by changing pulse duration between 60, 90, and 120 us, and secondly by altering current or voltage by the same ratios. Tremor severity was categorized by two experienced clinicians. Figure 1 shows the effect of rate for each subject. A repeatedmeasures ANOVA showed a significant effect of rate (p < 0.001) with the 40 Hz rate producing worse tremor scores than all rates of 100 Hz and above. Two patients showed a U-shaped response with best tremor suppression between 100 and 130 Hz, whereas the remaining patients showed a trend for better tremor suppression as rate increased across the whole range. Paired t-tests showed no significant difference between changing charge per phase via pulse duration or current/voltage, although both these effects were small, leading to poor statistical power.
Fig.1 Results of experiment 1. Funding: Colonial Foundation, program, NHMRC.
Victorian
government
OIS
82 81 The influence of rate of stimulation and pulse duration on efficacy of deep brain stimulation for Essential Tremor C.M. McKay a,b,*, H.J. McDermott a,b, T. Perera a, R. Peppard c, M. Jones c, A.P. Vogel a,b a Bionics Institute, Australia
Navigated repetitive transcranial magnetic stimulation in stroke rehabilitation (randomize double-blind sham-controlled study) A.V. Chervyakov , A.G. Poydasheva , M.A. Nazarova , E.A. Zmeykina , N.A. Suponeva , V.V. Gnezditsky , L.A. Chernikova , M.A. Piradov Research Center of neurology Russian academy of medical sciences, Moscow, Russia