Journal of aging and physical activity, Jan 24, 2017
To examine the effect of physical capacity, on the relationship of Brain-Derived Neurotrophic Fac... more To examine the effect of physical capacity, on the relationship of Brain-Derived Neurotrophic Factor (BDNF) with cognitive function in people with PD. Serum BDNF levels were measured in 29 PD participants and 30 healthy controls. Cognitive function was assessed using the Montreal Cognitive Assessment (MOCA) scale. Physical capacity was evaluated using the six minute walk distance (6-MWD). Participants were categorized into low or high physical capacity group according to their 50(th) percentile 6-MWD. MOCA total score correlated with serum BDNF level (r= 0.44, P=0.012) in the entire PD sample. This correlation remained significant only in the low physical capacity group (r= 0.62; P=0.03) but not in the high physical capacity group (r= 0.31; P=0. 22). The relationship of BDNF with cognitive function might be dependent on physical capacity. The results are preliminary, thus future studies are needed to confirm these findings.
In the present work, the antioxidant activity of different solvent extracts of wheat (var. Inqala... more In the present work, the antioxidant activity of different solvent extracts of wheat (var. Inqalab 91) bran was evaluated following different antioxidant assays using canola oil as the oxidation substrate. The bran samples were extracted with 80% and 100% methanol and acetone. ...
Brain-derived neurotrophic factor (BDNF) and cognitive function are diminished in people with Par... more Brain-derived neurotrophic factor (BDNF) and cognitive function are diminished in people with Parkinson's disease (PD). The relationship of cognitive function and serum level of BDNF, however is yet to be examined. The aim of this study was to examine serum BDNF levels in PD. Subsequently, the relationship of cognitive function to the serum levels of BDNF was evaluated. Serum BDNF levels were measured in 29 idiopathic PD subjects and 30 healthy-matched controls using ELISA technique. Cognitive function was assessed using the Montreal Cognitive Assessment (MOCA) scale. Serum BDNF levels and MOCA total score were significantly lower (P<0.001) in PD patients versus healthy controls. MOCA total score correlated with serum BDNF (r=0.44; P=0.012) but not with age, years of education, duration of disease and severity of symptoms. The regression analysis showed that serum BDNF accounted (P=0.019) for 19% of MOCA total score variance. The data confirm lowered serum BDNF in PD. Additionally; it suggests that BDNF may play a role in the cognitive deficit of PD. Further studies are required to identify association of BDNF in cognitive decline with PD.
In the present work, the antioxidant activity of different solvent extracts of wheat (var. Inqala... more In the present work, the antioxidant activity of different solvent extracts of wheat (var. Inqalab 91) bran was evaluated following different antioxidant assays using canola oil as the oxidation substrate. The bran samples were extracted with 80% and 100% methanol and acetone. ...
Deep brain stimulation (DBS) therapy currently relies on a transcranial neurosurgical technique t... more Deep brain stimulation (DBS) therapy currently relies on a transcranial neurosurgical technique to implant one or more electrode leads into the brain parenchyma. In this study, we used computational modeling to investigate the feasibility of using an endovascular approach to target DBS therapy. Image-based anatomical reconstructions of the human brain and vasculature were used to identify 17 established and hypothesized anatomical targets of DBS, of which five were found adjacent to a vein or artery with intraluminal diameter ≥1 mm. Two of these targets, the fornix and subgenual cingulate white matter (SgCwm) tracts, were further investigated using a computational modeling framework that combined segmented volumes of the vascularized brain, finite element models of the tissue voltage during DBS, and multi-compartment axon models to predict the direct electrophysiological effects of endovascular DBS. The models showed that: (1) a ring-electrode conforming to the vessel wall was more efficient at neural activation than a guidewire design, (2) increasing the length of a ring-electrode had minimal effect on neural activation thresholds, (3) large variability in neural activation occurred with suboptimal placement of a ring-electrode along the targeted vessel, and (4) activation thresholds for the fornix and SgCwm tracts were comparable for endovascular and stereotactic DBS, though endovascular DBS was able to produce significantly larger contralateral activation for a unilateral implantation. Together, these results suggest that endovascular DBS can serve as a complementary approach to stereotactic DBS in select cases.
Deep brain stimulation (DBS) in the ventral intermediate nucleus of thalamus (Vim) is known to ex... more Deep brain stimulation (DBS) in the ventral intermediate nucleus of thalamus (Vim) is known to exert a therapeutic effect on postural and kinetic tremor in patients with essential tremor (ET). For DBS leads implanted near the caudal border of Vim, however, there is an increased likelihood that one will also induce paresthesia side-effects by stimulating neurons within the sensory pathway of the ventral caudal (Vc) nucleus of thalamus. The aim of this computational study was to (1) investigate the neuronal pathways modulated by therapeutic, sub-therapeutic and paresthesia-inducing DBS settings in three patients with ET and (2) determine how much better an outcome could have been achieved had these patients been implanted with a DBS lead containing directionally segmented electrodes (dDBS). Multi-compartment neuron models of the thalamocortical, cerebellothalamic and medial lemniscal pathways were first simulated in the context of patient-specific anatomies, lead placements and programming parameters from three ET patients who had been implanted with Medtronic 3389 DBS leads. The models showed that in these patients, complete suppression of tremor was associated most closely with activating an average of 62% of the cerebellothalamic afferent input into Vim (n = 10), while persistent paresthesias were associated with activating 35% of the medial lemniscal tract input into Vc thalamus (n = 12). The dDBS lead design demonstrated superior targeting of the cerebello-thalamo-cortical pathway, especially in cases of misaligned DBS leads. Given the close proximity of Vim to Vc thalamus, the models suggest that dDBS will enable clinicians to more effectively sculpt current through and around thalamus in order to achieve a more consistent therapeutic effect without inducing side-effects.
The effects of deep brain stimulation (DBS) on motor cortex circuitry in Essential tremor (ET) an... more The effects of deep brain stimulation (DBS) on motor cortex circuitry in Essential tremor (ET) and Parkinson's disease (PD) patients are not well understood, in part, because most imaging modalities have difficulty capturing and localizing motor cortex dynamics on the same temporal scale as motor symptom expression. Here, we report on the use of magnetoencephalography (MEG) to characterize sources of postural tremor activity within the brain of an ET/PD patient and the effects of bilateral subthalamic nucleus DBS on these sources. Recordings were performed during unilateral and bilateral DBS at stimulation amplitudes of 0 V, 1 V, and 3 V corresponding to no therapy, subtherapeutic, and therapeutic configurations, respectively. Dipole source localization in reference to the postural tremor frequency recorded with electromyography (EMG) showed prominent sources in both right and left motor cortices when no therapy was provided. These sources dissipated as the amplitude of stimulation increased to a therapeutic level (P = 0.0062). Coherence peaks between the EMG and MEG recordings were seen at both 4 Hz, postural tremor frequency, and at 8 Hz, twice the tremor frequency, with no therapy. Both peaks were reduced with therapeutic DBS. These results demonstrate the capabilities of MEG to record cortical dynamics of tremor during deep brain stimulation and suggest that MEG could be used to examine DBS in the context of motor symptoms of PD and of ET.
Most Parkinson&am... more Most Parkinson's disease patients will receive levodopa therapy, and of these, the majority will develop some levodopa-induced complications. For many patients, the first complication to develop is the decline in the duration of therapeutic benefit of each levodopa dose, a phenomenon commonly termed 'wearing-off'. There is already extensive literature documenting the epidemiology and management of wearing-off in Parkinson's disease patients of western descent. However, data derived from these studies might not always apply to patients of Asian descent due to genetic variations, differences in co-morbidities or non-availability of certain drugs. This review summarizes the current literature regarding the epidemiology of wearing-off in Asian (including Arab) patients and discusses the management issues in the context of drug availability in Asia.
Journal of aging and physical activity, Jan 24, 2017
To examine the effect of physical capacity, on the relationship of Brain-Derived Neurotrophic Fac... more To examine the effect of physical capacity, on the relationship of Brain-Derived Neurotrophic Factor (BDNF) with cognitive function in people with PD. Serum BDNF levels were measured in 29 PD participants and 30 healthy controls. Cognitive function was assessed using the Montreal Cognitive Assessment (MOCA) scale. Physical capacity was evaluated using the six minute walk distance (6-MWD). Participants were categorized into low or high physical capacity group according to their 50(th) percentile 6-MWD. MOCA total score correlated with serum BDNF level (r= 0.44, P=0.012) in the entire PD sample. This correlation remained significant only in the low physical capacity group (r= 0.62; P=0.03) but not in the high physical capacity group (r= 0.31; P=0. 22). The relationship of BDNF with cognitive function might be dependent on physical capacity. The results are preliminary, thus future studies are needed to confirm these findings.
In the present work, the antioxidant activity of different solvent extracts of wheat (var. Inqala... more In the present work, the antioxidant activity of different solvent extracts of wheat (var. Inqalab 91) bran was evaluated following different antioxidant assays using canola oil as the oxidation substrate. The bran samples were extracted with 80% and 100% methanol and acetone. ...
Brain-derived neurotrophic factor (BDNF) and cognitive function are diminished in people with Par... more Brain-derived neurotrophic factor (BDNF) and cognitive function are diminished in people with Parkinson's disease (PD). The relationship of cognitive function and serum level of BDNF, however is yet to be examined. The aim of this study was to examine serum BDNF levels in PD. Subsequently, the relationship of cognitive function to the serum levels of BDNF was evaluated. Serum BDNF levels were measured in 29 idiopathic PD subjects and 30 healthy-matched controls using ELISA technique. Cognitive function was assessed using the Montreal Cognitive Assessment (MOCA) scale. Serum BDNF levels and MOCA total score were significantly lower (P<0.001) in PD patients versus healthy controls. MOCA total score correlated with serum BDNF (r=0.44; P=0.012) but not with age, years of education, duration of disease and severity of symptoms. The regression analysis showed that serum BDNF accounted (P=0.019) for 19% of MOCA total score variance. The data confirm lowered serum BDNF in PD. Additionally; it suggests that BDNF may play a role in the cognitive deficit of PD. Further studies are required to identify association of BDNF in cognitive decline with PD.
In the present work, the antioxidant activity of different solvent extracts of wheat (var. Inqala... more In the present work, the antioxidant activity of different solvent extracts of wheat (var. Inqalab 91) bran was evaluated following different antioxidant assays using canola oil as the oxidation substrate. The bran samples were extracted with 80% and 100% methanol and acetone. ...
Deep brain stimulation (DBS) therapy currently relies on a transcranial neurosurgical technique t... more Deep brain stimulation (DBS) therapy currently relies on a transcranial neurosurgical technique to implant one or more electrode leads into the brain parenchyma. In this study, we used computational modeling to investigate the feasibility of using an endovascular approach to target DBS therapy. Image-based anatomical reconstructions of the human brain and vasculature were used to identify 17 established and hypothesized anatomical targets of DBS, of which five were found adjacent to a vein or artery with intraluminal diameter ≥1 mm. Two of these targets, the fornix and subgenual cingulate white matter (SgCwm) tracts, were further investigated using a computational modeling framework that combined segmented volumes of the vascularized brain, finite element models of the tissue voltage during DBS, and multi-compartment axon models to predict the direct electrophysiological effects of endovascular DBS. The models showed that: (1) a ring-electrode conforming to the vessel wall was more efficient at neural activation than a guidewire design, (2) increasing the length of a ring-electrode had minimal effect on neural activation thresholds, (3) large variability in neural activation occurred with suboptimal placement of a ring-electrode along the targeted vessel, and (4) activation thresholds for the fornix and SgCwm tracts were comparable for endovascular and stereotactic DBS, though endovascular DBS was able to produce significantly larger contralateral activation for a unilateral implantation. Together, these results suggest that endovascular DBS can serve as a complementary approach to stereotactic DBS in select cases.
Deep brain stimulation (DBS) in the ventral intermediate nucleus of thalamus (Vim) is known to ex... more Deep brain stimulation (DBS) in the ventral intermediate nucleus of thalamus (Vim) is known to exert a therapeutic effect on postural and kinetic tremor in patients with essential tremor (ET). For DBS leads implanted near the caudal border of Vim, however, there is an increased likelihood that one will also induce paresthesia side-effects by stimulating neurons within the sensory pathway of the ventral caudal (Vc) nucleus of thalamus. The aim of this computational study was to (1) investigate the neuronal pathways modulated by therapeutic, sub-therapeutic and paresthesia-inducing DBS settings in three patients with ET and (2) determine how much better an outcome could have been achieved had these patients been implanted with a DBS lead containing directionally segmented electrodes (dDBS). Multi-compartment neuron models of the thalamocortical, cerebellothalamic and medial lemniscal pathways were first simulated in the context of patient-specific anatomies, lead placements and programming parameters from three ET patients who had been implanted with Medtronic 3389 DBS leads. The models showed that in these patients, complete suppression of tremor was associated most closely with activating an average of 62% of the cerebellothalamic afferent input into Vim (n = 10), while persistent paresthesias were associated with activating 35% of the medial lemniscal tract input into Vc thalamus (n = 12). The dDBS lead design demonstrated superior targeting of the cerebello-thalamo-cortical pathway, especially in cases of misaligned DBS leads. Given the close proximity of Vim to Vc thalamus, the models suggest that dDBS will enable clinicians to more effectively sculpt current through and around thalamus in order to achieve a more consistent therapeutic effect without inducing side-effects.
The effects of deep brain stimulation (DBS) on motor cortex circuitry in Essential tremor (ET) an... more The effects of deep brain stimulation (DBS) on motor cortex circuitry in Essential tremor (ET) and Parkinson's disease (PD) patients are not well understood, in part, because most imaging modalities have difficulty capturing and localizing motor cortex dynamics on the same temporal scale as motor symptom expression. Here, we report on the use of magnetoencephalography (MEG) to characterize sources of postural tremor activity within the brain of an ET/PD patient and the effects of bilateral subthalamic nucleus DBS on these sources. Recordings were performed during unilateral and bilateral DBS at stimulation amplitudes of 0 V, 1 V, and 3 V corresponding to no therapy, subtherapeutic, and therapeutic configurations, respectively. Dipole source localization in reference to the postural tremor frequency recorded with electromyography (EMG) showed prominent sources in both right and left motor cortices when no therapy was provided. These sources dissipated as the amplitude of stimulation increased to a therapeutic level (P = 0.0062). Coherence peaks between the EMG and MEG recordings were seen at both 4 Hz, postural tremor frequency, and at 8 Hz, twice the tremor frequency, with no therapy. Both peaks were reduced with therapeutic DBS. These results demonstrate the capabilities of MEG to record cortical dynamics of tremor during deep brain stimulation and suggest that MEG could be used to examine DBS in the context of motor symptoms of PD and of ET.
Most Parkinson&am... more Most Parkinson's disease patients will receive levodopa therapy, and of these, the majority will develop some levodopa-induced complications. For many patients, the first complication to develop is the decline in the duration of therapeutic benefit of each levodopa dose, a phenomenon commonly termed 'wearing-off'. There is already extensive literature documenting the epidemiology and management of wearing-off in Parkinson's disease patients of western descent. However, data derived from these studies might not always apply to patients of Asian descent due to genetic variations, differences in co-morbidities or non-availability of certain drugs. This review summarizes the current literature regarding the epidemiology of wearing-off in Asian (including Arab) patients and discusses the management issues in the context of drug availability in Asia.
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Papers by Jawad Bajwa