Grant A Bateman

John Hunter Hospital, New Lambton, New South Wales, Australia

Are you Grant A Bateman?

Claim your profile

Publications (49)215.54 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: The use of perfusion imaging to guide selection of patients for stroke thrombolysis remains controversial because of lack of supportive phase three clinical trial evidence. We aimed to measure the outcomes for patients treated with intravenous recombinant tissue plasminogen activator (rtPA) at a comprehensive stroke care facility where perfusion computed tomography was routinely used for thrombolysis eligibility decision assistance. Our overall hypothesis was that patients with 'target' mismatch on perfusion computed tomography would have improved outcomes with rtPA. This was a prospective cohort study of consecutive ischaemic stroke patients who fulfilled standard clinical/non-contrast computed tomography eligibility criteria for treatment with intravenous rtPA, but for whom perfusion computed tomography was used to guide the final treatment decision. The 'real-time' perfusion computed tomography assessments were qualitative; a large perfusion computed tomography ischaemic core, or lack of significant perfusion lesion-core mismatch were considered relative exclusion criteria for thrombolysis. Specific volumetric perfusion computed tomography criteria were not used for the treatment decision. The primary analysis compared 3-month modified Rankin Scale in treated versus untreated patients after 'off-line' (post-treatment) quantitative volumetric perfusion computed tomography eligibility assessment based on presence or absence of 'target' perfusion lesion-core mismatch (mismatch ratio >1.8 and volume >15 ml, core <70 ml). In a second analysis, we compared outcomes of the perfusion computed tomography-selected rtPA-treated patients to an Australian historical cohort of non-contrast computed tomography-selected rtPA-treated patients. Of 635 patients with acute ischaemic stroke eligible for rtPA by standard criteria, thrombolysis was given to 366 patients, with 269 excluded based on visual real-time perfusion computed tomography assessment. After off-line quantitative perfusion computed tomography classification: 253 treated patients and 83 untreated patients had 'target' mismatch, 56 treated and 31 untreated patients had a large ischaemic core, and 57 treated and 155 untreated patients had no target mismatch. In the primary analysis, only in the target mismatch subgroup did rtPA-treated patients have significantly better outcomes (odds ratio for 3-month, modified Rankin Scale 0-2 = 13.8, P < 0.001). With respect to the perfusion computed tomography selected rtPA-treated patients (n = 366) versus the clinical/non-contrast computed tomography selected rtPA-treated patients (n = 396), the perfusion computed tomography selected group had higher adjusted odds of excellent outcome (modified Rankin Scale 0-1 odds ratio 1.59, P = 0.009) and lower mortality (odds ratio 0.56, P = 0.021). Although based on observational data sets, our analyses provide support for the hypothesis that perfusion computed tomography improves the identification of patients likely to respond to thrombolysis, and also those in whom natural history may be difficult to modify with treatment. © The Author (2015). Published by Oxford University Press on behalf of the Guarantors of Brain.
    Brain 03/2015; DOI:10.1093/brain/awv071 · 10.23 Impact Factor
  • XII International Conference on Cognitive Neuroscience (ICON-XII); 01/2015
  • [Show abstract] [Hide abstract]
    ABSTRACT: Background. Upper-limb (UL) dysfunction is experienced by up to 75% of patients poststroke. The greatest potential for functional improvement is in the first month. Following reperfusion, evidence indicates that neuroplasticity is the mechanism that supports this recovery. Objective. This preliminary study hypothesized increased activation of putative motor areas in those receiving intensive, task-specific UL training in the first month poststroke compared with those receiving standard care. Methods. This was a single-blinded, longitudinal, randomized controlled trial in adult patients with an acute, first-ever ischemic stroke; 23 participants were randomized to standard care (n = 12) or an additional 30 hours of task-specific UL training in the first month poststroke beginning week 1. Patients were assessed at 1 week, 1 month, and 3 months poststroke. The primary outcome was change in brain activation as measured by functional magnetic resonance imaging. Results. When compared with the standard-care group, the intensive-training group had increased brain activation in the anterior cingulate and ipsilesional supplementary motor areas and a greater reduction in the extent of activation (P = .02) in the contralesional cerebellum. Intensive training was associated with a smaller deviation from mean recovery at 1 month (Pr>F0 = 0.017) and 3 months (Pr>F = 0.006), indicating more consistent and predictable improvement in motor outcomes. Conclusion. Early, more-intensive, UL training was associated with greater changes in activation in putative motor (supplementary motor area and cerebellum) and attention (anterior cingulate) regions, providing support for the role of these regions and functions in early recovery poststroke. © The Author(s) 2014.
    Neurorehabilitation and neural repair 12/2014; DOI:10.1177/1545968314562647 · 4.62 Impact Factor
  • Source
    Grant A Bateman, Sabbir H Siddique
    [Show abstract] [Hide abstract]
    ABSTRACT: Background The lack of absorption of CSF at the vertex in chronic hydrocephalus has been ascribed to an elevation in the arachnoid granulation outflow resistance (Rout). The CSF infusion studies measuring Rout are dependent on venous sinus pressure but little is known about the changes in pressure which occur throughout life or with the development of hydrocephalus. Methods Twenty patients with chronic hydrocephalus underwent MR venography and MR flow quantification techniques. The venous outflow pressure was estimated from the sinus blood flow and the cross-sectional area of the transverse sinuses. Adult controls as well as a normal young cohort were selected to estimate the change in sinus pressure which occurs throughout life and following the development of hydrocephalus. Significance was tested with a Student’s t-test. Results The size of the transverse sinuses was unchanged from the 1st to the 5th decade of life, indicating a stable outflow resistance. However, the blood flow was reduced by 42%, indicating a likely similar reduction in pressure gradient across the sinuses. The sinuses of hydrocephalus patients were 38% smaller than matched controls, indicating a 2.5 times increase in resistance. Despite the 24% reduction in blood flow, a significant increase in sinus pressure is suggested. Conclusions The size of the venous sinuses normally does not change over the age range investigated but sinus pressure is reduced proportional to an age-related blood flow reduction. Hydrocephalus is associated with much smaller sinuses than normal and an elevation in venous pressure may explain the lack of CSF absorption into the arachnoid granulations in chronic hydrocephalus.
    05/2014; 11:11. DOI:10.1186/2045-8118-11-11
  • CEREBROVASCULAR DISEASES; 01/2014
  • CEREBROVASCULAR DISEASES; 01/2014
  • Grant A Bateman, Michael Alber, Martin U Schuhmann
    [Show abstract] [Hide abstract]
    ABSTRACT: The etiology of external hydrocephalus is usually ascribed to either a delay in maturation or obstruction of the arachnoid granulations, but the arachnoid granulations are absent in neonates. Venous outflow stenoses, similar to those seen in idiopathic intracranial hypertension (IIH), have been described in external hydrocephalus. A reversible collapse of the sinuses is known to operate in IIH, but collapsible sinuses have not been previously described in infants with external hydrocephalus. Three infants with external hydrocephalus had magnetic resonance venography at differing time points during their illness. The venous sinuses varied in size depending on the cerebrospinal fluid pressure similar to IIH in adults. External hydrocephalus may be analogous to IIH in adults.
    Neuropediatrics 12/2013; 45(3). DOI:10.1055/s-0033-1363092 · 1.10 Impact Factor
  • Grant A Bateman
    [Show abstract] [Hide abstract]
    ABSTRACT: Object It is known that CSF diversion in neonatal hydrocephalus can significantly increase cerebral blood flow, suggesting that a rapidly reversible elevation in vascular resistance underlies this disorder. Various sites of vascular compression have been described in the literature, from the arterioles to the capillary bed to the venules and sinuses. The purpose of this study was to define the site of the hemodynamically significant vascular compression seen in neonatal hydrocephalus. Methods The author performed a retrospective review of all patients who, in the first 28 days of life, had undergone 3-T MRI examination, including MR venography and susceptibility weighted scanning, at a tertiary care referral hospital in the period from April 2010 to April 2013. The maximum size of the subependymal veins over the thalamus and transverse sinuses was measured. Results Three children with hydrocephalus were identified, and 10 children with a normal ventricular size served as controls. The subependymal veins were twice as prominent and the transverse sinuses were half as large in the patients with hydrocephalus compared with those in controls. Conclusions The hemodynamically significant elevation in vascular resistance, which occurs in neonatal hydrocephalus, appears to be located in the venous sinuses.
    Journal of Neurosurgery Pediatrics 11/2013; 13(2). DOI:10.3171/2013.10.PEDS13343 · 1.37 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Increased cerebral blood flow pulsatility is common in vascular dementia and is associated with macrostructural damage to cerebral white matter or leukoaraiosis (LA). In this study, we examine whether cerebral blood flow pulsatility is associated with macrostructural and microstructural changes in cerebral white matter in older adults with no or mild LA and no evidence of dementia. Diffusion Tensor Imaging was used to measure fractional anisotropy (FA), an index of the microstructural integrity of white matter, and radial diffusivity (RaD), a measure sensitive to the integrity of myelin. When controlling for age, increased arterial pulsation was associated with deterioration in both measures of white matter microstructure but not LA severity. A stepwise multiple linear regression model revealed that arterial pulsatility index was the strongest predictor of FA (R = 0.483, adjusted R (2) = 0.220), followed by LA severity, but not age. These findings suggest that arterial pulsatility may provide insight into age-related reduction in white matter FA. Specifically, increased arterial pulsatility may increase perivascular shear stress and lead to accumulation of damage to perivascular oligodendrocytes, resulting in microstructural changes in white matter and contributing to proliferation of LA over time. Changes in cerebral blood flow pulsatility may therefore provide a sensitive index of white matter health that could facilitate the early detection of risk for perivascular white matter damage and the assessment of the effectiveness of preventative treatment targeted at reducing pulsatility.
    Frontiers in Human Neuroscience 11/2013; 7:782. DOI:10.3389/fnhum.2013.00782 · 2.90 Impact Factor
  • Australian Physiotherapy Association Conference 2013. Journal abstract published in Journal of Physiotherapy, (e-Suppl. 2013 APA Conference Abstracts), 169., Melbourne, Australia.; 10/2013
  • Grant A Bateman
    [Show abstract] [Hide abstract]
    ABSTRACT: Symptomatic shunt malfunction without ventricular enlargement is known as slit ventricle syndrome (SVS). Patients presenting with this syndrome are not a homogeneous group. Of the 5 different types classified by Rekate, Type 1 is caused by CSF overdrainage and is associated with low pressures; Types 2 and 3 are associated with shunt blockage and elevated CSF pressures; Type 4 is cephalocranial disproportion that increases brain parenchymal pressure but not CSF pressure; and Type 5 is headache unrelated to shunt function. The low and normal CSF pressure types are relatively well understood, but the high-pressure forms are more problematic. In the high-pressure forms of SVS it is said that the lack of ventricular dilation is related to a reduction in brain compliance analogous to idiopathic intracranial hypertension or pseudotumor cerebri. Despite this, there is little evidence in the literature to support this conjecture. With this in mind, 3 cases of SVS associated with elevated CSF pressure are presented. The MR venogram findings and hemodynamics of these 3 cases are shown to be identical to those of pseudotumor cerebri. A literature review indicates that an underlying venous impairment may be functioning in the patients who re-present with small ventricles following shunt malfunction.
    Journal of Neurosurgery 08/2013; 119(6). DOI:10.3171/2013.7.JNS13390 · 3.15 Impact Factor
  • Grant A Bateman
    Journal of Neurosurgery 08/2013; DOI:10.3171/2011.2.JNS11216 · 3.15 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Background Manual therapy of the cervical spine has occasionally been associated with serious adverse events involving compromise of the craniocervical arteries. Ultrasound studies have shown certain neck positions can alter craniocervical arterial blood flow velocities, however, findings are conflicting. Knowledge about the effects of neck position on blood flow may assist clinicians avoid potentially hazardous practices.Objective To examine the effects of selected manual therapeutic interventions on blood flow in the craniocervical arteries and blood supply to the brain using magnetic resonance angiography (MRA)DesignThe study was an experimental observational MRI study.Method Healthy adult participants were imaged using MRA in the following neck positions: neutral, rotation, rotation/distraction (similar to a Cyriax manipulation), C1-C2 rotation (similar to a Maitland or osteopathic manipulation), and distraction.ResultsTwenty healthy participants with a mean age of 33 years were imaged using 3T MRA. All participants had normal vascular anatomy. Average inflow to the brain in neutral was 6.98 ml/s and was not significantly changed by any of the test positions. There was no significant difference in flow in any of the four arteries in any position from neutral, despite large individual variations.LimitationsOnly healthy asymptomatic individuals were investigated and a short section of the arteries only were imaged.Conclusions Blood flow to the brain does not appear to be compromised by positions commonly utilised in manual therapy. Positions using end-range neck rotation and distraction do not appear to be more hazardous to cerebral circulation than more segmentally localised techniques.
    Physical Therapy 06/2013; 93(11). DOI:10.2522/ptj.20120477 · 3.25 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The olfactory bulb (OB) receives extensive cholinergic input from the basal forebrain and is affected very early in Alzheimer's disease (AD). We speculated that an olfactory 'stress test' (OST), targeting the OB, might be used to unmask incipient AD. We investigated if change in olfactory performance following intranasal atropine was associated with several known antecedents or biomarkers of AD. We measured change in performance on the University of Pennsylvania Smell Identification Test (UPSIT) in the left nostril before (20-items) and after (remaining 20-items) intranasal administration of 1 mg of atropine. We administered cognitive tests, measured hippocampal volume from MRI scans and recorded Apolipoprotein E genotype as indices relevant to underlying AD. In a convenience sample of 56 elderly individuals (14 probable AD, 13 cognitive impairment no dementia, 29 cognitively intact) the change in UPSIT score after atropine ('atropine effect' = AE) correlated significantly with demographically scaled episodic memory score (r = 0.57, p < 0.001) and left hippocampal volume (LHCV) (r = 0.53, p < 0.001). Among non-demented individuals (n = 42), AE correlated with episodic memory (r = 0.52, p < 0.001) and LHCV (r = 0.49, p < 0.001) and hierarchical linear regression models adjusted for age, gender, education, and baseline UPSIT showed that the AE explained more variance in memory performance (24%) than did LHCV (15%). The presence of any APOE ϵ4 allele was associated with a more negative AE (p = 0.014). The OST using atropine as an olfactory probe holds promise as a simple, inexpensive screen for early and preclinical AD and further work, including longitudinal studies, is needed to explore this possibility.
    BMC Neurology 05/2012; 12:24. DOI:10.1186/1471-2377-12-24 · 2.49 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Intravenous alteplase is the only approved treatment for acute ischemic stroke. Tenecteplase, a genetically engineered mutant tissue plasminogen activator, is an alternative thrombolytic agent. In this phase 2B trial, we randomly assigned 75 patients to receive alteplase (0.9 mg per kilogram of body weight) or tenecteplase (0.1 mg per kilogram or 0.25 mg per kilogram) less than 6 hours after the onset of ischemic stroke. To favor the selection of patients most likely to benefit from thrombolytic therapy, the eligibility criteria were a perfusion lesion at least 20% greater than the infarct core on computed tomographic (CT) perfusion imaging at baseline and an associated vessel occlusion on CT angiography. The coprimary end points were the proportion of the perfusion lesion that was reperfused at 24 hours on perfusion-weighted magnetic resonance imaging and the extent of clinical improvement at 24 hours as assessed on the National Institutes of Health Stroke Scale (NIHSS, a 42-point scale on which higher scores indicate more severe neurologic deficits). The three treatment groups each comprised 25 patients. The mean (±SD) NIHSS score at baseline for all patients was 14.4±2.6, and the time to treatment was 2.9±0.8 hours. Together, the two tenecteplase groups had greater reperfusion (P=0.004) and clinical improvement (P<0.001) at 24 hours than the alteplase group. There were no significant between-group differences in intracranial bleeding or other serious adverse events. The higher dose of tenecteplase (0.25 mg per kilogram) was superior to the lower dose and to alteplase for all efficacy outcomes, including absence of serious disability at 90 days (in 72% of patients, vs. 40% with alteplase; P=0.02). Tenecteplase was associated with significantly better reperfusion and clinical outcomes than alteplase in patients with stroke who were selected on the basis of CT perfusion imaging. (Funded by the Australian National Health and Medical Research Council; Australia New Zealand Clinical Trials Registry number, ACTRN12608000466347.).
    New England Journal of Medicine 03/2012; 366(12):1099-107. DOI:10.1056/NEJMoa1109842 · 54.42 Impact Factor
  • Grant A Bateman, Kirk M Brown
    [Show abstract] [Hide abstract]
    ABSTRACT: Despite 100 years of study, the theories of cerebrospinal fluid (CSF) formation and absorption remain controversial. Measuring CSF flow through the aqueduct using magnetic resonance imaging (MRI) provides a unique insight into the physiology of CSF hydrodynamics. The published data in adults tend to refute rather than support the prevailing theories of CSF flow. There are limited data regarding this metric in children. This paper seeks to measure the aqueduct flow in normal and hydrocephalic children to help formulate a more complete theory of CSF flow. Twenty-four children with communicating hydrocephalus aged from 4 months to 16 years underwent MRI flow quantification of the aqueduct measuring the net flow. The patients were compared to 19 controls. The controls revealed two different flow patterns: (1) an infantile pattern characterized by flow directed into the ventricular system and (2) a mature pattern with flow directed out of the ventricles, similar to the published findings in adults. In infants with communicating hydrocephalus, the aqueduct flow changed direction but was of similar magnitude compared with the controls (p = 0.001). In the older hydrocephalic children, the flow was elevated 7-fold, but the direction was unchanged compared to the controls (p = 0.002). There is an abrupt change in the aqueduct CSF flow pattern at the age of 2 years from an infantile pattern to a mature pattern. These findings together with the findings in hydrocephalic children do not support the current theories of CSF hydrodynamics. A new theory of CSF circulation based on capillary absorption is presented.
    Child s Nervous System 01/2012; 28(1):55-63. DOI:10.1007/s00381-011-1617-4 · 1.16 Impact Factor
  • Grant A Bateman
    Child s Nervous System 12/2011; 27(12):2033-4. DOI:10.1007/s00381-011-1610-y · 1.16 Impact Factor
  • Grant A Bateman, Brett D Napier
    [Show abstract] [Hide abstract]
    ABSTRACT: The cause of external hydrocephalus in infants is largely unknown. However, familial macrocephaly and delayed maturation of the arachnoid granulations are thought to play a part in the idiopathic cases. Secondary cases of external hydrocephalus are associated with hemorrhage, meningitis, and elevated venous pressure. Recently, elevated venous pressure has been shown to be a much more common cause of communicating hydrocephalus in children than previously thought. The purpose of this study is to investigate venous pressure as a cause of external hydrocephalus. Six children with external hydrocephalus underwent an MRI examination including MR venography and MR flow quantification techniques. A chart review was performed to correlate the clinical findings with the MR findings. Six children with normal head circumferences and growth profile served as controls. The net aqueduct flow in both normal and hydrocephalic children was into the ventricles. There was a spectrum of blood flow findings in the infants with hydrocephalus. (1) Those with normal arterial inflow showed venous outflow stenoses or anomalies. (2) Those with normal MR venograms tended to have elevated cerebral blood inflow. The absorption of CSF in infants is into the capillary bed of the deep white matter rather than the arachnoid granulations. Absorption into a capillary bed depends on hydrostatic pressure. Similar to older children with communicating hydrocephalus, the infants in this cohort with external hydrocephalus showed evidence of an elevation in venous pressure. Elevated venous pressure may be a much more common cause of external hydrocephalus than previously recognized.
    Child s Nervous System 08/2011; 27(12):2087-96. DOI:10.1007/s00381-011-1549-z · 1.16 Impact Factor
  • Grant A Bateman
    Neurosurgical Review 10/2010; 33(4):505-6. DOI:10.1007/s10143-010-0281-6 · 1.86 Impact Factor
  • Alzheimer's and Dementia 07/2010; 6(4). DOI:10.1016/j.jalz.2010.05.1247 · 17.47 Impact Factor

Publication Stats

1k Citations
215.54 Total Impact Points

Institutions

  • 2002–2015
    • John Hunter Hospital
      New Lambton, New South Wales, Australia
  • 2014
    • Hunter New England Health
      New Lambton, New South Wales, Australia
  • 2006–2014
    • University of Newcastle
      • Hunter Medical Research Institute (HMRI)
      Newcastle, New South Wales, Australia