Case Report: Focal, generalized, or both: does generalized network involvement preclude successful epilepsy surgery?

We present two cases with focal seizures where scalp electroencephalography (EEG) had prominent features of a developmental and epileptic encephalopathy (DEE): Case 1: a 17-year-old male with complex motor seizures whose EEG demonstrated a slow spike-and-wave pattern and generalized paroxysmal fast activity (GPFA). Case 2: a 12-year-old male with startle-induced asymmetric tonic seizures whose EEG also had a slow spike-and-wave pattern. Both patients had intracranial EEG assessment, and focal cortical resections resulted in long-term seizure freedom and resolution of generalized findings. These cases exemplify patients with focal epilepsy with networks that share similarities to generalized epilepsies, and importantly, these features did not preclude curative epilepsy surgery.

Clinical features associated with epilepsy occurrence, resolution, and drug resistance in children with cerebral palsy: A population-based study.

AIM: To investigate clinicoradiological features associated with epilepsy, its resolution, and drug resistance in children with cerebral palsy (CP). METHOD: Data were gathered from the New South Wales/Australian Capital Territory CP Register, encompassing children with CP born between 2003 and 2015 (n = 1916). Clinical features and the severity of impairments were compared among three groups: children with current epilepsy (n = 604), those with resolved epilepsy by age 5 years (n = 109), and those without epilepsy (n = 1203). Additionally, a subset of the registry cohort attending Children's Hospital Westmead (n = 256) was analysed to compare epilepsy and treatment characteristics between drug-responsive (n = 83) and drug-resistant groups (n = 147) using logistic regression and hierarchical cluster analysis. RESULTS: Manual Ability Classification System levels IV and V, intellectual impairment, and vision impairment were found to be associated with epilepsy in children with CP on multivariable analysis (p < 0.01). Moderate to severe intellectual impairment and bilateral spastic CP were independent positive and negative predictors of epilepsy persistence at the age of 5 years respectively (p < 0.05). Microcephaly and multiple seizure types were predictors of drug-resistant epilepsy (area under the receiver operating characteristic curve of 0.83; 95% confidence interval 0.77-0.9). Children with a known genetic cause (14%) and CP epilepsy surgery group (4.3%) formed specific clinical subgroups in CP epilepsy. INTERPRETATION: Our study highlights important clinical associations of epilepsy, its resolution, and treatment response in children with CP, providing valuable knowledge to aid in counselling families and identifying distinct prognostic groups for effective medical surveillance and optimal treatment.

Predictors of longitudinal seizure outcomes after epilepsy surgery in childhood.

There is a paucity of data on longitudinal seizure outcome of children undergoing epilepsy surgery. All children (n = 132) who underwent resective epilepsy surgery from January 1998 to December 2015 were identified. Relevant clinical, neurophysiological, imaging, surgical and seizure outcome data were extracted. Multivariable logistic regression analysis and Kaplan-Meier survival with Cox proportional hazard modelling were performed. The mean age at surgery was 7.8 years (range 0.2-17.9). 71% were seizure-free at a mean follow up of 5.3 ± 2.7 years. Of those who were seizure-free, 65 patients were able to completely wean off anti- seizure medications successfully. Using survival analysis, the probability of Engel Class I outcome at one year after surgery was 81% (95% confidence interval [CI] 87%-75%). This dropped to 73% at two years (95% CI 81%-65%), 58% at five years (95% CI 67.8%-48%), and 47% at ten years. Proportional hazard modelling showed that the presence of moderate to severe developmental disability (HR 6.5; p = 0.02) and lack of complete resection (HR 0.4; p = 0.02) maintain association as negative predictors of seizure-free outcome. Our study demonstrates favorable long-term seizure control following pediatric epilepsy surgery and highlights important predictors of seizure outcome guiding case selection and counseling of expectations prior to surgery.

Deficits in all aspects of social competence identified in children who have undergone epilepsy surgery.

Research on social competence of children who undergo epilepsy surgery is limited. This cross-sectional study aimed to determine the frequency and pattern of impairments in social competence (domains: social skills, social adjustment, and social performance) in a cohort of children who underwent surgery for intractable epilepsy at a single epilepsy surgical center. In addition, we explored the relationships between social competence with epilepsy variables, surgical variables, and seizure outcomes. Fifteen children (5 to 16 years) who underwent focal cortical resection for intractable epilepsy more than 2 years ago (2.58-7.42 years) participated. Parents completed standardized, age-normed questionnaires, assessing three domains of social competence. Demographic and clinical information were obtained from parents and medical records and verified by Pediatric Neurologists and Clinical Nurse Consultant. Individual and group analyses were conducted. Seventy-three percent (n = 11/15) of children were seizure-free. Individual analyses revealed high rates of impairments (scores >1 standard deviation of the mean); 11 out of 15 children (73.3%) obtained a score that fell in the impaired range on at least one domain of social competence, with 5 of these 15 children (30.0%) obtaining impaired scores across domains. Conversely, group analyses of questionnaires completed by parents revealed that compared with norms, children had significant difficulties in all domains of social competence: social skills, social adjustment, and social performance. No significant relationships were found between domains of social competence and epilepsy and surgical variables. In conclusion, children who underwent epilepsy surgery have significantly reduced social competence relative to the norms. Longitudinal studies examining social competence pre- and postsurgery are needed to determine whether surgery improves social competence and whether this is dependent on epilepsy outcomes.

A study of perfusion changes with Insula Epilepsy using SPECT.

PURPOSE: The non-invasive localisation of insular lobe epilepsy is a challenge. We aimed to determine if ictal SPECT is a reliable adjunctive test in insular cases and to explore its role in the tailoring of intracranial strategies. METHOD: From a dataset of patients who underwent SEEG between December 2012 and December 2016, we collected patients with focal insular onset epilepsy. We examined semiology, EEG, PET and SPECT hyperperfusion pattern with SISCOM. We also reviewed relevant literature. RESULTS: 5 patients were identified, 4 females, from a dataset of 51 patients. Median age of seizure onset was 8 years old (8 months to 10 years). All patients had an ictal SPECT during pre-surgical work-up: median injection time was 7 s (3-17 sec) from clinical onset, and median seizure duration was 42 s (11-85 sec). Insula cortex showed focal hyperaemia in four patients, all bilateral, with the greatest hyperperfusion contralateral to the ictal onset in two cases, using SISCOM threshold at 1.5 standard deviation. Other sites with hyperaemia included basal ganglia and middle temporal gyrus. The SEEG confirmed insular onset seizures in all the cases. All patients had epilepsy surgery and were seizure free at 21 to 50 months follow up. The results from the literature review showed frequent hyperperfusion in structures outside insula and frequently over the contralateral hemisphere. CONCLUSIONS: This study highlights the technical limitations of SPECT when attempting to assess seizures arising from the insula. Our findings and the literature show ictal SPECT can be localising but falsely lateralising in seizures arising from the insula.

Seizure outcome after corpus callosotomy in a large paediatric series.

AIM: To describe 20 years of experience with corpus callosotomy at Great Ormond Street Hospital for Children, London and the Children's Hospital at Westmead, Sydney. METHOD: Records of patients who underwent corpus callosotomy between January 1995 and December 2015 were reviewed. Complications of surgery and changes in seizure type and frequency, injuries, and use of antiepileptic drugs were recorded. Drop attacks were analysed using Kaplan-Meier event-free survival curves. Multivariable regression analysis was used to assess the effect of clinical characteristics on outcome at last follow-up. RESULTS: Inclusion criteria were met for 55 patients younger than 18 years of age. Median follow-up length was 36 months. At the last follow-up, 26 out of 55 patients (47%) had rare or no drop attacks. In those without a good outcome at final follow-up, 26 out of 29 (90%) had drop attacks return within 12 months of surgery. There were no preoperative predictors of developing drop attacks postoperatively. The median number of antiepileptic drugs significantly reduced from three to two. Transient neurological complications were experienced by 11 out of 55 patients (20%) and 6 out of 55 patients had surgical complications (11%). INTERPRETATION: Corpus callosotomy is a well-tolerated procedure that is effective at reducing the severity of drop attacks in paediatric patients. Drop attacks that do return are likely to do so within 12 months and the number of antiepileptic drugs can be significantly reduced. WHAT THIS PAPER ADDS: Corpus callosotomy is an effective palliative treatment and well tolerated in children. Good outcomes for the first 12 months after surgery were likely to continue. The number of antiepileptic drugs can be significantly reduced after corpus callosotomy. Patients with fewer than three types of seizure had better outcomes. There were fewer injuries from drop attacks after surgery.

Cerebrospinal fluid cyto-/chemokine profile during acute herpes simplex virus induced anti-N-methyl-d-aspartate receptor encephalitis and in chronic neurological sequelae.

AIM: To examine the cytokine/chemokine profile of cerebrospinal fluid (CSF) during acute herpes simplex virus-induced N-methyl-d-aspartate receptor (NMDAR) autoimmunity and in chronic/relapsing post-herpes simplex virus encephalitis (HSE) neurological syndromes. METHOD: We measured longitudinal serial CSF cyto-/chemokines (n=34) and a glial marker (calcium-binding astroglial protein, S100B) in one patient during acute HSE and subsequent anti-NMDAR encephalitis, and compared the results with those from two patients with anti-NMDAR encephalitis without preceding HSE. We also compared cyto-/chemokines in cross-sectional CSF samples from three children with previous HSE who had ongoing chronic or relapsing neurological symptoms (2yr 9 mo-16y after HSE) with those in a group of children having non-inflammatory neurological conditions (n=20). RESULTS: Acute HSE showed elevation of a broad range of all T-helper-subset-related cyto-/chemokines and S100B whereas the post-HSE anti-NMDAR encephalitis phase showed persistent elevation of two of five T-helper-1 (chemokine [C-X-C motif] ligand 9 [CXCL9], CXCL10), three of five predominantly B-cell (CXCL13, CCL19, a proliferation-inducing ligand [APRIL])-mediated cyto-/chemokines, and interferon-α. The post-HSE anti-NMDAR encephalitis inflammatory response was more pronounced than anti-NMDAR encephalitis. All three chronic post-HSE cases showed persistent elevation of CXCL9, CXCL10, and interferon-α, and there was histopathological evidence of chronic lymphocytic inflammation in one biopsied case 7 years after HSE. Two of three chronic cases showed a modest response to immune therapy. INTERPRETATION: HSE-induced anti-NMDAR encephalitis is a complex and pronounced inflammatory syndrome. There is persistent CSF upregulation of cyto-/chemokines in chronic or relapsing post-HSE neurological symptoms, which may be modifiable with immune therapy. The elevated cyto-/chemokines may be targets of monoclonal therapies.

Corpus callosotomy outcomes in pediatric patients: A systematic review.

OBJECTIVE: Corpus callosotomy is a palliative neurosurgical treatment for patients with either generalized or multifocal refractory epilepsy and injurious drop attacks. This report aims to systematically review the pediatric literature. METHODS: Medline, Embase, Web of Knowledge, and Scopus were searched systematically for published articles on treatment outcomes of corpus callosotomy for refractory epilepsy. Studies were included if the patient population was younger than 18 at the time of surgery and median follow-up was >1 year. Studies were excluded if resective surgery was also performed. RESULTS: A total of 12 articles met inclusion criteria. All articles were retrospective case series, with the exception of one being a prospectively designed retrospective case series. There was very little agreement among authors on the definition of a good seizure outcome. Articles that used the Engel classification found that 88.2% of total corpus callosotomy patients had a worthwhile reduction in seizures compared with 58.6% of patients who underwent anterior corpus callosotomy (p < 0.05). Drop attacks improved from corpus callosotomy more than other generalized seizure types. Reported complications were minor in all but one patient, and one death was reported. Transient disconnection syndrome was significantly more likely in total corpus callosotomy than in anterior corpus callosotomy (12.5% vs. 0%; p < 0.05). Improvements in quality of life, behavior, and intelligence/development quotient, as well as parental satisfaction, were generally correlated with seizure outcome. There was no postcallosotomy change in the number of antiepileptic drugs. SIGNIFICANCE: Total corpus callosotomy was significantly more likely to result in a reduction in seizures. Anterior corpus callosotomy was unlikely to result in disconnection syndrome. Although all of the papers drew a similar conclusion, the quality of evidence was low. At best, the evidence raises the hypothesis that corpus callosotomy is a safe and effective treatment for refractory generalized epilepsy. It is clear that a case-control or randomized trial is warranted.

Outcome of Early Juvenile Onset Metachromatic Leukodystrophy After Unrelated Cord Blood Transplantation: A Case Series and Review of the Literature.

The purpose of this study was to determine whether transplantation of umbilical cord blood from unrelated donors before the development of symptoms could halt the progression of early juvenile onset cases of MLD in whom the disease was diagnosed based on the family history. Three asymptomatic children (aged 2 years 4 months, 2 years 8 months and 5 years 5 months, two of whom were sisters) underwent unrelated umbilical cord blood transplantation (UCBT) and two untreated symptomatic siblings were included in the study. In 14-year and 6-year follow-ups after transplantation, clinical examination, ARSA enzyme levels, neurophysiological, neuroimaging, and psychological status were assessed. All three transplanted patients remain well, and the parameters evaluated remain stable. Of the treated patients, the two sisters had ongoing evidence of demyelinating sensorimotor neuropathy on nerve conduction tests, and with a early sensorimotor neuropathy in the older sister , and the other patient has mild intellectual impairment. One of the two un-transplanted controls, 15 years after MLD diagnosis, has relentlessly progressed to full dependency with epilepsy, severe mental retardation, dystonic movements, dysphagia and recurrent respiratory problems. Six years after diagnosis, the other control has a slowly progressive course with spastic dystonic quadriplegia, epilepsy, dysphagia, continual drooling and incontinence. Our data show that, in comparison with their untreated siblings, UCBT significantly slowed the progression of the disease in the treated patients. We conclude that UCBT benefits children with pre-symptomatic early juvenile onset MLD by favourably altering the natural history of the disease.

Movement disorders in children with anti-NMDAR encephalitis and other autoimmune encephalopathies.

Accurate recognition of movement disorder phenomenology may differentiate children with anti-N-methyl D-aspartate receptor (NMDAR) encephalitis, autoimmune basal ganglia encephalitis (BGE), and Sydenham's chorea (SC). Three neurologists blinded to the diagnoses recorded dominant and associated movement disorders seen on videos of 31 patients with anti-NMDAR encephalitis (n = 10), BGE (n = 12), and SC (n = 9). Stereotypy was only seen in anti-NMDAR encephalitis (8/10) and not in BGE and SC (P < 0.001). Perseveration was only seen in anti-NMDAR encephalitis (5/10) and not in BGE and SC (P < 0.001). Akinesia was more commonly seen in BGE (5/12) than in anti-NMDAR encephalitis (1/10, P = 0.097). Tremor was more commonly seen in BGE (5/12) than in anti-NMDAR encephalitis (1/10, P = 0.097). Chorea was seen in all groups: anti-NMDAR encephalitis (4/10), BGE (3/12), and SC (9/9). Likewise, dystonia was seen in all groups: anti-NMDAR encephalitis (6/10), BGE (7/12), and SC (2/9). Stereotypies or perseveration are suggestive of anti-NMDAR encephalitis, whereas their absence and the presence of akinesia and tremor is more suggestive of BGE. Chorea and dystonia are least discriminating.

A type I interferon signature identifies bilateral striatal necrosis due to mutations in ADAR1.

BACKGROUND: We recently observed mutations in ADAR1 to cause a phenotype of bilateral striatal necrosis (BSN) in a child with the type I interferonopathy Aicardi-Goutières syndrome (AGS). We therefore decided to screen patients with apparently non-syndromic BSN for ADAR1 mutations, and for an upregulation of interferon-stimulated genes (ISGs). METHODS: We performed Sanger sequencing of ADAR1 in a series of patients with BSN presenting to us during our routine clinical practice. We then undertook detailed clinical and neuroradiological phenotyping in nine mutation-positive children. We also measured the expression of ISGs in peripheral blood from these patients, and in children with BSN who did not have ADAR1 mutations. RESULTS: Nine ADAR1 mutation-positive patients from seven families demonstrated an acute (five cases) or subacute (four cases) onset of refractory, four-limb dystonia starting between 8 months and 5 years of age. Eight patients were developmentally normal at initial presentation. In seven cases, the disease was inherited as an autosomal recessive trait, while two related patients were found to have a heterozygous (dominant) ADAR1 mutation. All seven mutation-positive patients assayed showed an upregulation of ISGs (median: 12.50, IQR: 6.43-36.36) compared to controls (median: 0.93, IQR: 0.57-1.30), a so-called interferon signature, present many years after disease onset. No interferon signature was present in four children with BSN negative for mutations in ADAR1 (median: 0.63, IQR: 0.47-1.10). CONCLUSIONS: ADAR1-related disease should be considered in the differential diagnosis of apparently non-syndromic BSN with severe dystonia of varying evolution. The finding of an interferon signature provides a useful screening test for the presence of ADAR1 mutations in this context, and may suggest novel treatment approaches.

Reduction of seizure frequency after epilepsy surgery in a patient with STXBP1 encephalopathy and clinical description of six novel mutation carriers.

Mutations in STXBP1 have been identified in a subset of patients with early onset epileptic encephalopathy (EE), but the full phenotypic spectrum remains to be delineated. Therefore, we screened a cohort of 160 patients with an unexplained EE, including patients with early myoclonic encephalopathy (EME), Ohtahara syndrome, West syndrome, nonsyndromic EE with onset in the first year, and Lennox-Gastaut syndrome (LGS). We found six de novo mutations in six patients presenting as Ohtahara syndrome (2/6, 33%), West syndrome (1/65, 2%), and nonsyndromic early onset EE (3/64, 5%). No mutations were found in LGS or EME. Only two of four mutation carriers with neonatal seizures had Ohtahara syndrome. Epileptic spasms were present in five of six patients. One patient with normal magnetic resonance imaging (MRI) but focal seizures underwent epilepsy surgery and seizure frequency dropped drastically. Neuropathology showed a focal cortical dysplasia type 1a. There is a need for additional neuropathologic studies to explore whether STXBP1 mutations can lead to structural brain abnormalities.

Expanding the molecular basis and phenotypic spectrum of X-linked Joubert syndrome associated with OFD1 mutations.

Using a combination of linkage mapping and massively parallel sequencing of the X-chromosome exome, we identified an 18-bp deletion in exon 8 of the oral-facial-digital syndrome type 1 (OFD1) gene in a family with X-linked Joubert syndrome (JBTS10). The deletion results in an in-frame deletion of six amino acids. New features not noted in the two previously reported cases of X-linked Joubert syndrome include the presence of polycystic kidney disease, polymicrogyria and hydrocephalus. Our study further underlines the power of genetic mapping combined with massively parallel sequencing as a powerful tool for novel disease gene and mutation discovery.

Immune-mediated steroid-responsive epileptic spasms and epileptic encephalopathy associated with VGKC-complex antibodies.

Autoantibodies that bind to voltage-gated potassium-channel complex proteins (VGKC-complex antibodies) occur frequently in adults with limbic encephalitis presenting with cognitive impairment and seizures. Recently, VGKC-complex antibodies have been described in a few children with limbic encephalitis, and children with unexplained encephalitis presenting with status epilepticus. We report a case of infantile-onset epileptic spasms and developmental delay compatible with epileptic encephalopathy. Our patient was a female infant, aged 4 months at presentation. She had evidence of immune activation in the central nervous system with elevated cerebrospinal fluid neopterin and mirrored oligoclonal bands, which prompted testing for autoantibodies. VGKC-complex antibodies were elevated (201 pmol/L, normal<100), but extended antibody testing, including leucine-rich glioma-inactivated 1 (LGI1) and contactin-associated protein 2 (CASPR2), was negative. The patient showed a partial response to steroid treatment, which was started late in the disease course. On review at 13 months of age, her development was consistent with an age of 5 to 6 months. These results suggest that VGKC-complex antibodies might represent a marker of immune therapy responsiveness in a subgroup of patients with infantile epileptic encephalopathy.

Pediatric sciatic neuropathy associated with neoplasms.

Seven children with sciatic neuropathy associated with an underlying neoplasm are reported. Clinical presentation, electrophysiological data, imaging, pathology, and/or autopsy results are described. Pain and weakness, primarily foot drop, were the most common presenting symptoms. The mechanism of sciatic neuropathy was varied and included: nerve infiltration by the adjacent neoplasm (neuroblastoma, rhabdomyosarcoma, and leukemic or lymphomatous infiltration); an expanding, intrinsic neurogenic tumor (perineurioma); or intraoperative stretch injury (osteosarcoma resection). The prognosis for sciatic nerve recovery was good among children who survived their associated cancer. Three children died from the cancer or complications of treatment. One child with perineurioma remained clinically stable, and two children improved after treatment of their neoplasm.

N-methyl-D-aspartate receptor antibodies in pediatric dyskinetic encephalitis lethargica.

Encephalitis lethargica (EL) describes an encephalitis with psychiatric, sleep, and extrapyramidal movement disorders. Dyskinetic and parkinsonian forms have been described. EL shares clinical features with the anti-N-methyl-D-aspartate receptor (NMDAR-Ab) encephalitis. We studied 20 sera from pediatric patients with contemporary EL. Ten sera (from 2 males and 8 females, aged 1.3-13 years) and 6/6 cerebrospinal fluid samples were positive for NMDAR-Ab. NMDAR-Ab-positive patients had dyskinesias, agitation, seizures, and insomnia, whereas parkinsonism and somnolence dominated in the NMDAR-Ab-negative children. We were unable to identify any tumors. The dyskinetic form of EL is an NMDAR-Ab encephalitis and can affect very young children.

Risk factors for complications during intracranial electrode recording in presurgical evaluation of drug resistant partial epilepsy.

BACKGROUND: Intracranial electrode monitoring is still required in epilepsy surgery; however, it is associated with significant morbidity. OBJECTIVE: To identify risk factors associated with complications during invasive intracranial EEG monitoring. MATERIALS AND METHODS: Retrospective study of all patients undergoing invasive monitoring at Westmead between 1988-2004. From detailed chart reviews, the following variables were recorded: duration of intracranial monitoring, the site of grid implantation, number of grids and electrodes, seizure frequency, postoperative complications and seizure outcome. RESULTS: Seventy-one patients (median age: 24 years) underwent subdural electrode implantation; 62% had extratemporal lobe epilepsy and 46% were non-lesional. Of the 58 monitored patients who had cortical resections, 45 had good seizure outcomes. Complications related to subdural electrode implantation included transient complications requiring no treatment (12.7%), transient complications requiring treatment (9.9%) and two deaths (2.8%). Specific complications included subdural haemorrhage, transient neurological deficit, infarction and osteomyelitis. The two deaths occurred within 48 h of implantation were related to raised intracranial pressure (one venous infarction, one unexplained). Complications were associated with maximal size of grid (p < 0.001), greater number of electrodes (p < 0.001), electrode density per cortical surface implanted (p < 0.001), right central surface implantation (p = 0.003) and left central surface implantation (p = 0.013). Multiple logistic regression identified larger size grids and right central surface implantation as independent predictors of complications. CONCLUSION: There are significant complications during intracranial EEG evaluations but the majority of these are transient. We found a relationship between the size of the electrode arrays and the incidence of complications. The results of this study have been used to modify our implantation and monitoring protocols.

Contemporary encephalitis lethargica presenting with agitated catatonia, stereotypy, and dystonia-parkinsonism.

Encephalitis lethargica (EL) syndrome was classically described by Von Economo and has somnolent-ophthalmoplegic, hyperkinetic, and amyostatic-akinetic forms. We describe 2 recent cases of EL characterized by an acute encephalitis with mixed movement disorders (dystonia-Parkinsonism plus stereotypy) and psychiatric disorders (agitated catatonia, coprolalia, and echo phenomena). Both patients suffered concurrent hyperkinetic and Parkinsonian features resulting in therapeutic challenges. Bradykinetic features responded to dopamine replacement therapy and both patients also had adverse affects to dopamine antagonists (oculogyric crises plus neuroleptic malignant syndrome). Investigation was unremarkable other than the presence of CSF lymphocytosis and oligoclonal bands. Despite prolonged in-patient stays and intensive care management, both patients have made complete recoveries. We believe these cases support the hypothesis that this syndrome is an inflammatory encephalitis that specifically effects dopamine neurotransmission.

T2 hyperintensities in children with neurofibromatosis type 1 and their relationship to cognitive functioning.

BACKGROUND: Neurofibromatosis type 1 (NF1) is a single gene disorder associated with a high frequency of cognitive deficits and a complex cognitive phenotype. These cognitive deficits have been associated with focal areas of high signal intensity on T2 weighted MRI images but the relationship remains controversial. METHOD: A cohort of 76 children with NF1 and 45 unaffected sibling controls (aged 8-16 years) underwent extensive neuropsychological assessment, with the NF1 children having MRI examinations. RESULTS: The presence or number of T2 hyperintensities (T2H) was not associated with cognitive dysfunction. However, the location of discrete (well circumscribed) T2H in the thalamus was associated with severe and generalised cognitive impairment. More diffuse lesions in the thalamus were also associated with reductions in IQ but the effects were less marked compared with the discrete lesions. Comparing children with NF1 to their unaffected siblings revealed more subtle effects of the lesions on cognitive ability. CONCLUSIONS: T2H cannot be used in general as a radiological marker for cognitive deficits in children with NF1; however, lesions in the thalamus are strongly associated with cognitive impairment. It is possible that lesions in the thalamus in conjunction with more general thalamic hypometabolism may compound the level of thalamic dysfunction, resulting in cognitive deficits well beyond those produced by T2H in other regions.

Age-related findings on MRI in neurofibromatosis type 1.

BACKGROUND: T2 hyperintensities (T2H) on MRI are the most common CNS lesions in individuals with neurofibromatosis type 1 (NF1). OBJECTIVES: The aim was to determine the frequency, signal characteristics and localization of T2H at different ages. In addition, we examined the sensitivity of different MR imaging sequences in detecting these lesions. MATERIALS AND METHODS: We studied prospectively a cohort of children, adolescents and young adults with NF1 using T2-volume (T2-V) and conventional MRI sequences. Lesions were designated as either discrete or diffuse, and the region of signal abnormality was recorded. A total of 103 patients were studied (age range 8.0-25.4 years, mean 13.9 years). RESULTS: The frequency, size, and intensity of T2H decreased with age in the basal ganglia (BG) and the cerebellum/brainstem (CB/BS). The majority of thalamic and CB/BS lesions were diffuse. Of the total cohort, 80% had diffuse bilateral hippocampal hyperintensities and 18.4% had hemispheric lesions best demonstrated on FLAIR; there was no significant difference in the frequency or signal intensity of hemispheric lesions with age. CONCLUSION: Lesions in the cerebral hemispheres and hippocampus imaged by MR do not change in prevalence over time, suggesting a different pathological basis from the lesions in the in BG and CB/BS that resolve with age. FLAIR and T2-V sequences are more sensitive in detecting lesions than standard T2-weighted sequences.