Jinendra Ekanayake

University College London | UCL · Academic Department of neurosurgery

Background: Neurofeedback training is a closed-loop neuromodulatory technique in which real-time feedback of brain activity and connectivity is provided to the participant for the purpose of volitional neural control. Through practice and reinforcement, such learning has been shown to facilitate measurable changes in brain function and behavior....

The COVID-19 pandemic has forced medical education to change and adapt. Although the majority of courses were able to be delivered virtually through online platforms, practical cadaveric courses such as Anatomy and Surgical courses had to either be halted or cancelled. Some practical courses continued to run in a socially distanced way, with strict...

Background: The endonasal approach is the gold standard for the resection of pituitary tumours, with either microscopic endonasal transsphenoidal (MET) or endoscopic endonasal transsphenoidal (EET) technique. Advantages and disadvantages of both techniques have been widely described in the literature, although limited attention has been paid to its...

Neural activation causes a complex change in neurophysiological parameters of the cerebral blood flow (CBF). Functional magnetic resonance imaging (fMRI) measures one of these neurophysiological parameters, which is the blood oxygen level dependent (BOLD) response. The general linear model (GLM) used in fMRI task experiments relates activated brain...

Brain tissue segmentation from multimodal MRI is a key building block of many neuroscience analysis pipelines. It could also play an important role in many clinical imaging scenarios. Established tissue segmentation approaches have however not been developed to cope with large anatomical changes resulting from pathology. The effect of the presence...

Can we change our perception by controlling our brain activation? Awareness during binocular rivalry is shaped by the alternating perception of different stimuli presented separately to each monocular view. We tested the possibility of causally influencing the likelihood of a stimulus entering awareness. To do this, participants were trained with n...

The Dice score is widely used for binary segmentation due to its robustness to class imbalance. Soft generalisations of the Dice score allow it to be used as a loss function for training convolutional neural networks (CNN). Although CNNs trained using mean-class Dice score achieve state-of-the-art results on multi-class segmentation, this loss func...

The Dice score is widely used for binary segmentation due to its robustness to class imbalance. Soft generalisations of the Dice score allow it to be used as a loss function for training convolutional neural networks (CNN). Although CNNs trained using mean-class Dice score achieve state-of-the-art results on multi-class segmentation, this loss func...

We describe a novel patient position for endoscopic transphenoidal surgery - the 'conversational position'. This position is a safe and effective alternative to the standard supine position, incorporating a semi-sitting position with the additional innovation of achieving a 'conversational position' by flexing the neck and turning the patient's hea...

Brain-computer-interfaces (BCI) provide a means of using human brain activations to control devices for communication. Until now this has only been demonstrated in primary motor and sensory brain regions, using surgical implants or non-invasive neuroimaging techniques. Here, we provide proof-of-principle for the use of higher-order brain regions in...

Brain tumour segmentation plays a key role in computer-assisted surgery. Deep neural networks have increased the accuracy of automatic segmentation significantly, however these models tend to generalise poorly to different imaging modalities than those for which they have been designed, thereby limiting their applications. For example, a network ar...

The Dice score is widely used for binary segmentation due to its robustness to class imbalance. Soft generalisations of the Dice score allow it to be used as a loss function for training convolutional neural networks (CNN). Although CNNs trained using mean-class Dice score achieve state-of-the-art results on multi-class segmentation, this loss func...

Brain tumour segmentation plays a key role in computer-assisted surgery. Deep neural networks have increased the accuracy of automatic segmentation significantly, however these models tend to generalise poorly to different imaging modalities than those for which they have been designed, thereby limiting their applications. For example, a network ar...

Non-invasive brain-computer interfaces (BCIs) seek to enable or restore brain function by using neuroimaging e.g. functional magnetic resonance imaging (fMRI), to engage brain activations without the need for explicit behavioural output or surgical implants. Brain activations are converted into output signals, for use in communication interfaces, m...

Results ICPM was undertaken for a number of different conditions including undiagnosed headache (20.4%), IIH (28.7%), NPH (5.3%), high-pressure hydrocephalus (eg congenital/ post-traumatic/post-SAH) (17.2%) and Chiari malformations/syringomyelia (13.6%). Indications for ICPM included headache (74.0%), visual disturbance (6.2%), gait disturbance (6....

Normal pressure Hydrocephalus (NPH) is predominantly treated with a ventriculoperitoneal shunt (VPS) resulting in improvement in the Hakim triad (mobility, cognitive function, urinary continence). There are a population of patients who experience an improvement in symptoms post shunt insertion followed by a subsequent deterioration in their conditi...

The landmark discovery that control of autonomic physiology could be ‘learned’ using biofeedback was first demonstrated with heart rate [1,2]. Biofeedback control has since been demonstrated with physiological variables such as regional cerebral blood flow, and end tidal carbon dioxide, with therapeutic application in conditions including migraine...

The ever present need to balance over drainage with under drainage in hydrocephalus has required innovations including adjustable valves with antigravity devices. These are activated in the vertical position to prevent siphoning. We describe a group of patients who presented with unexplained under drainage caused by activation of antigravity shunt...

In response to the 2013 ISH-CSF task force review on comorbidities in NPH we assessed 73 patients who were diagnosed with NPH and underwent shunt surgery at our tertiary neurosurgical unit between August 2008 and August 2012.

Chiari malformation (CM) describes cerebellar tonsillar descent below the level of the foramen magnum. It is commonly associated with syringomyelia and often presents with headache (1). The conventional surgical treatment for symptomatic patients is foramen magnum decompression (FMD) (2) which carries a significant burden of operative morbidity (3)...

Background Intracranial pressure monitoring is commonly undertaken to assess and manage acute patients following head injury. However, ICP monitoring can also be a useful diagnostic tool in the management of CSF dynamics in elective patients. To date, there is little published research to suggest how long these elective patients require ICP monitor...

Obstruction to cerebrospinal fluid (CSF) flow in idiopathic normal pressure hydrocephalus (iNPH) results in reduced CSF total tau (t-tau) and amyloid-β 42 (Aβ42) protein concentrations [1]. Restoration of normal CSF flow dynamics with ventriculoperitoneal (VP) shunt allows these biomarkers to clear from extracellular fluid into the CSF(1). CSF biom...

Selecting probable idiopathic normal pressure hydrocephalus (INPH) patients for shunt insertion presents a challenge because of coexisting comorbidities and other conditions that could mimic NPH. The characteristic appearance of DESH (Disproportionately Enlarged Subarachnoid Space Hydrocephalus) on brain imaging has been shown to have a high positi...

Idiopathic Intracranial Hypertension (IIH) is characterised by an increased intracranial pressure (ICP) in the absence of any central nervous system disease or structural abnormality, and normal CSF composition. Management becomes complicated once surgical intervention is required. Venous sinus stenosis has been suggested as a possible aetiology fo...

Benign Intracranial hypertension (BIH) is commonly associated with venous sinus stenosis. Increasingly, this is treated endovascularly with stent insertion. However, this treatment modality is still controversial. Clinical improvement post stent insertion has been described. Little is known about long-term control of intracranial pressure (ICP). In...

Cerebrospinal fluid (CSF) leak following spinal surgery is a relatively common surgical complication. A small group of CSF leak patients require multiple surgical repairs and prolonged hospital admission. Spinal CSF leaks are usually classically associated with symptoms of low intracranial pressure (ICP). However, there is a paucity of literature i...

Preoperative embolization of meningiomas remains contentious, with persisting uncertainty over the safety and efficacy of this adjunctive technique. To evaluate the safety of presurgical embolization of meningiomas and its impact on subsequent transfusion requirement, with respect to the extent of embolization and technique used. 117 consecutive pa...

Neurofeedback using real-time fMRI (rtfMRI) enables voluntary control of activity within a target brain region. By subsequently testing how such voluntary control of brain activity affects perception or behaviour, it is possible to establish a causal link between brain activity and behaviour We hypothesized that neurofeedback training of higher ord...

BACKGROUND:: Preoperative embolization of meningiomas remains contentious, with persisting uncertainty over the safety and efficacy of this adjunctive technique. OBJECTIVE:: To evaluate the safety of presurgicalembolization of meningiomas and its impact on subsequent transfusion requirement, with respect to the extent of embolization and technique...

The use of interbody cages with bone autograft following anterior cervical discectomy is well documented. The use of high-speed drills in the drilling of the posterior osteophyte results in the production of bone dust with viable osteophytes. We report the use of the ANSPACH bone collector device, which can be connected to standard suction circuitr...

Purpose: The value of scalp recordings to localize and lateralize seizure onset in temporal lobe epilepsy has been assessed by comparing simultaneous scalp and intracranial foramen ovale (FO) recordings during presurgical assessment. The sensitivity of scalp recordings for detecting mesial temporal ictal onset has been compared with a "gold standa...