Association of structural brain networks with cognition in suspected epilepsy and epilepsy surgery

The human brain can be modelled as a network of interconnected anatomical regions using structural magnetic resonance imaging data. Understanding variations in network structure could help understand variations in higher brain functions such as cognition. This thesis investigates whether brain network structure is associated with cognition in patients investigated for suspected epilepsy and in those undergoing epilepsy surgery. Epilepsy is frequently associated with cognitive impairments and seizures are known to disrupt both structural and functional brain networks. First, a systematic literature review was undertaken to compare structural brain networks in epilepsy with healthy controls. Patients with epilepsy were found to have less efficient networks with increased average path lengths compared to healthy controls. Networks constructed from cortical thickness covariance also showed increased clustering coefficients compared to controls. Second, the association between network structure and cognitive dysfunction in a cohort of children undergoing investigation for suspected epilepsy was analysed. Patients with cognitive dysfunction had networks with longer average path lengths, longer normalised average path lengths, and lower global efficiency, even after controlling for the number and weight of network edges. These findings were consistent across network construction methods. Third, in a cohort of children undergoing resective epilepsy surgery, a post-operative increase in intelligence quotient was associated with increased global efficiency in the structural network within the healthy, contralateral non-operated hemisphere. Although cognition was associated with clinical features such as seizure frequency and age at onset of seizures, differences in network characteristics could not be completely explained by differences in clinical features. Different modelling techniques created different representative models but findings were broadly consistent across model types. This thesis suggests that the widespread alterations in brain structure described in epilepsy may lead to less efficient brain networks which could contribute to cognitive dysfunction. Adequately treating seizures in those with an efficient underlying brain network structure may facilitate cognitive development and allow patients to achieve their cognitive potential

Efficient organisation of the contralateral hemisphere connectome is associated with improvement in intelligence quotient after paediatric epilepsy surgery

ObjectiveAims of epilepsy surgery in childhood include optimising seizure control and facilitating cognitive development. Predicting which children will improve cognitively is challenging. We investigated the association of the pre-operative structural connectome of the contralateral non-operated hemisphere with improvement in intelligence quotient (IQ) post-operatively.MethodsConsecutive children who had undergone unilateral resective procedures for epilepsy at a single centre were retrospectively identified. We included those with pre-operative volume T1-weighted non-contrast brain magnetic resonance imaging (MRI), no visible contralateral MRI abnormalities, and both pre-operative and two years post-operative IQ assessment. The MRI of the hemisphere contralateral to the side of resection was anatomically parcellated into 34 cortical regions and the covariance of cortical thickness between regions was used to create binary and weighted group connectomes.ResultsEleven patients with a post-operative IQ increase of at least 10 points at two years were compared with twenty-four patients with no change in IQ score. Children who gained at least 10 IQ points post-operatively had a more efficiently structured contralateral hemisphere connectome with higher global efficiency (0.74) compared to those whose IQ did not change at two years (0.58, p=0.014). This was consistent across thresholds and both binary and weighted networks. There were no statistically significant group differences in age, sex, age at onset of epilepsy, pre-operative IQ, mean cortical thickness, side or site of procedure, two year post-operative Engel scores or use of anti-seizure medications between the two groups. ConclusionsSurgical procedures to reduce or stop seizures may allow children with an efficiently structured contralateral hemisphere to achieve their cognitive potential. <br/

Chronic idiopathic urinary retention:Comorbidity and outcome in 102 individuals

OBJECTIVES: Chronic Idiopathic urinary retention is poorly understood. One small study suggests higher than expected rates of functional neurological disorder and pain comorbidity which may have implications for understanding the disorder. We investigated the frequency of functional neurological disorder, chronic pain other medical and psychiatric comorbidity, triggers of urinary retention, results of urodynamic assessment, medication history, management, and outcome in patients with chronic idiopathic urinary retention.METHODS: A consecutive retrospective electronic notes analysis was undertaken of patients with chronic idiopathic urinary retention presenting to a secondary care urology clinic between Jan 2018-Jan 2021, with follow-up to their most recent urological appointment.RESULTS: 102 patients were identified (mean age of 41.9 years, 98% female). 25% had functional neurological disorder (n = 26), most commonly limb weakness (n = 19, 19%) and functional seizures (n = 16, 16%). Chronic pain (n = 58, 57%) was a common comorbidity. Surgical and medical riggers to urinary retention were found in almost half of patients (n = 49, 48%). 81% of patients underwent urodynamic assessment (n = 83). Most frequently no specific abnormality was reported (n = 30, 29%). Hypertonic urethral sphincter was the most identified urodynamic abnormality (n = 17, 17%). We noted high levels of opioid (n = 50, 49%) and benzodiazepine (n = 27, 26%) use. Urinary retention resolved in only a small number of patients (n = 6, 6%, median follow up 54 months), in three cases spontaneously.CONCLUSION: This preliminary data suggests idiopathic urinary retention is commonly comorbid with functional neurological disorder, and chronic pain, suggesting shared mechanisms.</p

Restoration of elective spine surgery during the first wave of COVID-19:a UK-wide British Association of Spine Surgeons (BASS) prospective, multicentre, observational study

AIMS: With resumption of elective spine surgery services in the UK following the first wave of the COVID-19 pandemic, we conducted a multicentre British Association of Spine Surgeons (BASS) collaborative study to examine the complications and deaths due to COVID-19 at the recovery phase of the pandemic. The aim was to analyze the safety of elective spinal surgery during the pandemic. METHODS: A prospective observational study was conducted from eight spinal centres for the first month of operating following restoration of elective spine surgery in each individual unit. Primary outcome measure was the 30-day postoperative COVID-19 infection rate. Secondary outcomes analyzed were the 30-day mortality rate, surgical adverse events, medical complications, and length of inpatient stay. RESULTS: In all, 257 patients (128 males) with a median age of 54 years (2 to 88) formed the study cohort. The mean number of procedures performed from each unit was 32 (16 to 101), with 118 procedures (46%) done as category three prioritization level. The majority of patients (87%) were low-medium “risk stratification” category and the mean length of hospital stay was 5.2 days. None of the patients were diagnosed with COVID-19 infection, nor was there any mortality related to COVID-19 during the 30-day follow-up period, with 25 patients (10%) having been tested for symptoms. Overall, 32 patients (12%) developed a total of 34 complications, with the majority (19/34) being grade 1 to 2 Clavien-Dindo classification of surgical complications. No patient required postoperative care in an intensive care setting for any unexpected complication. CONCLUSION: This study shows that safe and effective planned spinal surgical services can be restored avoiding viral transmission, with diligent adherence to national guidelines and COVID-19-secure pathways tailored according to the resources of the individual spinal units. Cite this article: Bone Jt Open 2021;2(12):1096–1101

Is mechanism of injury associated with outcome in spinal trauma? An observational cohort study from Tanzania

Background Traumatic spinal injury (TSI) is a disease of significant global health burden, particularly in low and middle-income countries where road traffic-related trauma is increasing. This study compared the demographics, injury patterns, and outcomes of TSI caused by road traffic accidents (RTAs) to non-traffic related TSI. Methods A retrospective analysis was conducted using a neurotrauma registry from the Muhimbili Orthopaedic Institute (MOI) in Tanzania, a national referral center for spinal injuries. Patient sociodemographic characteristics, injury level, and severity were compared across mechanisms of injury. Neurological improvement, neurological deterioration, and mortality were compared between those sustaining TSI through an RTA versus non-RTA, using univariable and multivariable analyses. Results A total of 626 patients were included, of which 302 (48%) were RTA-related. The median age was 34 years, and 532 (85%) were male. RTAs had a lower male preponderance compared to non-RTA causes (238/302, 79% vs. 294/324, 91%, p\u3c0.001) and a higher proportion of cervical injuries (144/302, 48% vs. 122/324, 38%, p\u3c0.001). No significant differences between RTA and non-RTA mechanisms were found in injury severity, time to admission, length of hospital stay, surgical intervention, neurological outcomes, or in-hospital mortality. Improved neurological outcomes were associated with incomplete injuries (AIS B-D), while higher mortality rates were linked to cervical injuries and complete (AIS A) injuries. Conclusion Our study in urban Tanzania finds no significant differences in outcomes between spinal injuries from road traffic accidents (RTAs) and non-RTA causes, suggesting the need for equitable resource allocation in spine trauma programs. Highlighting the critical link between cervical injuries and increased mortality, our findings call for targeted interventions across all causes of traumatic spinal injuries (TSI). We advocate for a comprehensive trauma care system that merges efficient pre-hospital care, specialized treatment, and prevention measures, aiming to enhance outcomes and ensure equity in trauma care in low- and middle-income countries

Efficient organisation of the contralateral hemisphere connectome is associated with improvement in intelligence quotient after paediatric epilepsy surgery

Objective: Aims of epilepsy surgery in childhood include optimising seizure control and facilitating cognitive development. Predicting which children will improve cognitively is challenging. We investigated the association of the pre-operative structural connectome of the contralateral non-operated hemisphere with improvement in intelligence quotient (IQ) post-operatively. Methods: Consecutive children who had undergone unilateral resective procedures for epilepsy at a single centre were retrospectively identified. We included those with pre-operative volume T1-weighted non-contrast brain magnetic resonance imaging (MRI), no visible contralateral MRI abnormalities, and both pre-operative and two years post-operative IQ assessment. The MRI of the hemisphere contralateral to the side of resection was anatomically parcellated into 34 cortical regions and the covariance of cortical thickness between regions was used to create binary and weighted group connectomes. Results: Eleven patients with a post-operative IQ increase of at least 10 points at two years were compared with twenty-four patients with no change in IQ score. Children who gained at least 10 IQ points post-operatively had a more efficiently structured contralateral hemisphere connectome with higher global efficiency (0.74) compared to those whose IQ did not change at two years (0.58, p = 0.014). This was consistent across thresholds and both binary and weighted networks. There were no statistically significant group differences in age, sex, age at onset of epilepsy, pre-operative IQ, mean cortical thickness, side or site of procedure, two year post-operative Engel scores or use of anti-seizure medications between the two groups. Conclusions: Surgical procedures to reduce or stop seizures may allow children with an efficiently structured contralateral hemisphere to achieve their cognitive potential

The association of structural connectome efficiency with cognition in children with epilepsy

Objective: Cognitive impairment is common in children with epilepsy (CWE), but understanding the underlying pathological processes is challenging. We aimed to investigate the association of structural brain network organisation with cognition. Methods: This was a retrospective cohort study of CWE without structural brain abnormalities, comparing whole brain network characteristics between those with cognitive impairment and those with intact cognition. We created structural whole-brain connectomes from anatomical and diffusion tensor magnetic resonance imaging using the number of streamlines and tract-averaged fractional anisotropy. We assessed the differences in average path length and global network efficiency between children with cognitive impairment and those without,using multivariable analyses to account for possible clinical group differences. Results: Twenty-eight CWE and cognitive impairment had lower whole brain network global efficiency compared with 34 children with intact cognition (0.54, standard deviation (SD):0.003 vs. 0.56, SD:0.002, p < 0.001), which is equivalent to longer normalized network average path lengths (1.14, SD:0.05 vs. 1.10, SD:0.02, p = 0.003). In multivariable logistic regression cognitive impairment was not significantly associated with age of onset, duration of epilepsy, or number of antiseizure medications, but was independently associated with daily seizures (p = 0.04) and normalized average path length (p = 0.007). Conclusions: Higher structural network average path length and lower global network efficiency may be imaging biomarkers of cognitive impairment in epilepsy. Understanding what leads to changes in structural connectivity could aid identification of modifiable risk factors for cognitive impairment. These findings are only applicable to the specific cohort studied, and further confirmation in other cohorts is required

More questions than answers to the diagnosis and management of cauda equina syndrome-Authors' reply

No abstract available