Combined Depth and Subdural Electrodes for Lateralization of the Ictal Onset Zone in Mesial Temporal Lobe Epilepsy with Hippocampal Sclerosis.

(1) Objective: This study aimed to explore the efficacy of conventional invasive techniques in confirming unilateral seizure onset localization in mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS) and to investigate the association between electrode type and intracranial electroencephalography (EEG) pattern. (2) Methods: This retrospective study encompasses patients diagnosed with MTLE-HS who underwent an invasive study prior to an anterior temporal lobectomy (ATL). Intracranial EEG features were assessed for 99 seizure events from 25 selected patients who achieved seizure remission with ATL after an invasive study using bilateral combined depth and subdural electrodes. Their findings were compared to those of 21 seizure events in eight patients who exhibited suboptimal seizure outcomes. (3) Results: For the distribution of electrodes that recorded the ictal onset, hippocampal depth electrodes recorded 96% of all seizure events, while subdural electrodes recorded 52%. Among the seizures recorded in subdural electrodes, 49% were localized in medial electrodes, with only 8% occurring in lateral electrodes. The initiation of seizures exclusively detected in hippocampal depth electrodes was associated with successful seizure remission, whereas those solely recorded in the lateral strip electrodes were often linked to refractory seizures after ATL. (4) Conclusions: These findings emphasize the importance of employing a combination of depth and subdural electrodes in invasive studies for patients with MTLE-HS to enhance the accuracy of lateralization. This also cautions against sole reliance on subdural electrodes without depth electrodes, which could lead to inaccurate localization.

Differences in theta coherence between spatial and nonspatial attention using intracranial electroencephalographic signals in humans.

A number of previous studies revealed the importance of the frontoparietal network for attention and preparatory top-down control. Here, we investigated the theta (7-9 Hz) coherence of the right frontoparietal networks to explore the differences in connectivity changes for the right frontoparietal regions during spatial attention (i.e., attention to a specific location rather than a specific feature) and nonspatial attention (i.e., attention to a specific feature rather than a specific location) tasks. The theta coherence in both tasks was primarily maintained at a preparatory state, decreases after stimulus onset, and recovers to the level of the preparatory state after the response time. However, the theta coherence of the frontoparietal network during spatial attention was immediately maintained after cue-onset, whereas for the case of nonspatial attention, it was immediately decreased after cue-onset. In addition, the connectivity of the right frontoparietal network, including the middle frontal gyrus and superior parietal lobe, were significantly higher for spatial attention rather than for nonspatial attention, suggesting that the dorsal parts of right frontoparietal network are more engaged in spatial-specific attention from the preparatory state. These findings also suggest that these two attention systems involve the use of different regional connectivity patterns, not only in the cognitive state, but in the preparatory state as well.

Semantic-hierarchical model improves classification of spoken-word evoked electrocorticography.

Classification of spoken word-evoked potentials is useful for both neuroscientific and clinical applications including brain-computer interfaces (BCIs). By evaluating whether adopting a biology-based structure improves a classifier's accuracy, we can investigate the importance of such structure in human brain circuitry, and advance BCI performance. In this study, we propose a semantic-hierarchical structure for classifying spoken word-evoked cortical responses. The proposed structure decodes the semantic grouping of the words first (e.g., a body part vs. a number) and then decodes which exact word was heard. The proposed classifier structure exhibited a consistent ∼10% improvement of classification accuracy when compared with a non-hierarchical structure. Our result provides a tool for investigating the neural representation of semantic hierarchy and the acoustic properties of spoken words in human brains. Our results suggest an improved algorithm for BCIs operated by decoding heard, and possibly imagined, words.

Spectral Analysis of Acceleration Data for Detection of Generalized Tonic-Clonic Seizures.

Generalized tonic-clonic seizures (GTCSs) can be underestimated and can also increase mortality rates. The monitoring devices used to detect GTCS events in daily life are very helpful for early intervention and precise estimation of seizure events. Several studies have introduced methods for GTCS detection using an accelerometer (ACM), electromyography, or electroencephalography. However, these studies need to be improved with respect to accuracy and user convenience. This study proposes the use of an ACM banded to the wrist and spectral analysis of ACM data to detect GTCS in daily life. The spectral weight function dependent on GTCS was used to compute a GTCS-correlated score that can effectively discriminate between GTCS and normal movement. Compared to the performance of the previous temporal method, which used a standard deviation method, the spectral analysis method resulted in better sensitivity and fewer false positive alerts. Finally, the spectral analysis method can be implemented in a GTCS monitoring device using an ACM and can provide early alerts to caregivers to prevent risks associated with GTCS.

Neural correlates of spatial and nonspatial attention determined using intracranial electroencephalographic signals in humans.

Few studies have directly compared the neural correlates of spatial attention (i.e., attention to a particular location) and nonspatial attention (i.e., attention to a feature in the visual scene) using well-controlled tasks. Here, we investigated the neural correlates of spatial and nonspatial attention in humans using intracranial electroencephalography. The topography and number of electrodes showing significant event-related desynchronization (ERD) or event-related synchronization (ERS) in different frequency bands were studied in 13 epileptic patients. Performance was not significantly different between the two conditions. In both conditions, ERD in the low-frequency bands and ERS in the high-frequency bands were present bilaterally in the parietal cortex (prominently on the right hemisphere) and frontal regions. In addition to these common changes, spatial attention involved right-lateralized activity that was maximal in the right superior parietal lobule (SPL), whereas nonspatial attention involved wider brain networks including the bilateral parietal, frontal, and temporal regions, but still had maximal activity in the right parietal lobe. Within the parietal lobe, spatial attention involved ERD or ERS in the right SPL, whereas nonspatial attention involved ERD or ERS in the right inferior parietal lobule. These findings reveal that common as well as different brain networks are engaged in spatial and nonspatial attention. Hum Brain Mapp 37:3041-3054, 2016. © 2016 The Authors Human Brain Mapping Published by Wiley Periodicals, Inc.

Changes in Central Auditory Processing in Patients with Mesial Temporal Lobe Epilepsy after Anterior Temporal Lobectomy with Amygdalohippocampectomy.

BACKGROUND AND PURPOSE: This study aimed to determine the effects of anterior temporal lobectomy with amygdalohippocampectomy (ATL-AH) on central auditory processing (CAP) in patients with mesial temporal lobe epilepsy with hippocampal sclerosis (mTLE-HS), and to identify factors that may contribute to the postoperative worsening of CAP. METHODS: Frequency-pattern, duration-pattern, and dichotic tests were performed before and after epilepsy surgery in 22 patients with normal hearing according to pure-tone audiometry. RESULTS: No significant difference in CAP scores was detected between pre- and postoperative tests, but there was a strong association between surgery in the language-dominant temporal lobe and postoperative worsening in the non-dominant-side dichotic test (p<0.05). The probability of a decreased performance in a non-dominant-side dichotic test after surgery was 7.5-fold greater in patients who underwent surgery on the dominant temporal lobe compared with the nondominant temporal lobe. No significant association of postoperative worsening in CAP with the verbal, nonverbal intelligence quotient, or right- or left-side lobectomy was noted. CONCLUSIONS: These results suggest that ATL-AH on the dominant side in patients with mTLE-HS worsens the CAP ability in the non-dominant-side dichotic test.

Diagnostic usefulness of T-cell based assays for tuberculous meningitis in HIV-uninfected patients.

OBJECTIVES: Early diagnosis and treatment of tuberculous meningitis (TBM) is essential for a positive outcome, but sensitive, specific, and rapid diagnostic tests for TBM are lacking. We evaluated the diagnostic utility of enzyme-linked immunosorbent spot (ELISPOT) assays in HIV-uninfected patients with suspected TBM. METHODS: All HIV-uninfected patients with suspected TBM were prospectively enrolled at a tertiary care hospital in an intermediate TB-burden country, during a 6-year period. ELISPOT assays were performed on peripheral blood mononuclear cells (PBMC) and cerebrospinal fluid-mononuclear cells (CSF-MC). RESULTS: Of the 276 evaluable patients, 90 (33%) were classified as having TBM (30 definite cases, 19 probable, and 41 possible), and 186 (67%) as having non-TBM. When comparing definite TBM versus non-TBM, the sensitivity and specificity of the PBMC ELISPOT assay (≥6 spots; manufacturer's recommended cut-off) for diagnosing TBM were 96% (95% CI, 82-100) and 58% (95% CI, 50-66), respectively. The CSF-MC ELISPOT assay (≥38 spots; receiver operating characteristic [ROC]-derived cut-off) was a useful rule-in test with specificity of 95% (96% CI, 90-98). Its sensitivity was 68% (95% CI, 45-86), which was superior those of AFB smear microscopy (14%; P < 0.001) and CSF Mycobacterium tuberculosis PCR (41%; P = 0.07). Combining this assay with M. tuberculosis PCR, clinical score, and both together increased sensitivity to 86%, 91%, and 95%, respectively, while retaining about 95% specificity. CONCLUSIONS: The CSF-MC ELISPOT assay appears to be a rapid and accurate rule-in test for the diagnosis of TBM and a useful adjunct for diagnosing TBM in HIV-uninfected patients.

Asymmetric behaviours of brain oscillations in the human hippocampus during spatial navigation tasks.

Hippocampal-dependent memory functions may be lateralized to the right hippocampus during spatial navigation. However, direct electrophysiological evidence supporting these findings in the bilateral hippocampi during spatial navigation has not been well documented in humans. We studied changes in brain oscillations between the dominant and the nondominant hippocampi during encoding periods of environmental novelty using spatial navigation tasks. Results showed that brain oscillations during the encoding period of spatial navigation increased significantly in the nondominant hippocampus compared with the dominant hippocampus. These findings provide direct electrophysiological evidence that the nondominant hippocampus plays a predominant role in spatial navigation.

Identifying clinical correlates for suicide among epilepsy patients in South Korea: A case-control study.

OBJECTIVE: Suicide is a major cause of premature mortality in patients with epilepsy. We aimed to identify the clinical correlates of suicide in these patients. METHODS: We conducted a matched, case-control study based on a clinical case registry of epilepsy patients (n = 35,638) treated between January 1994 and December 2011 at an academic tertiary medical center in Seoul, Korea. Each epilepsy patient in the suicide group (n = 74) was matched with three epilepsy patients in the nonsuicide group (n = 222) by age, gender, and approximate time at first treatment. The clinical characteristics of the patients in both groups were then compared. RESULTS: In a univariate analysis, seizure frequency during the year before suicide, use of antiepileptic drug polytherapy, lack of aura before seizure, diagnosis of temporal lobe epilepsy, use of levetiracetam, psychiatric comorbidity, and use of antidepressants were all significantly higher in the suicide group than in the nonsuicide group. Multivariate analysis revealed that a high seizure frequency (odds ratio [OR] 3.3, 95% confidence interval [CI] 1.04-10.2), a lack of aura before seizure (OR 4.0, 95% CI 1.7-9.3), temporal lobe epilepsy (OR 3.7, 95% CI 1.6-8.6), and use of levetiracetam (OR 7.6, 95% CI 1.1-53.7) and antidepressants (OR 7.2, 95% CI 1.5-34.1) were all associated with a higher probability of suicide. SIGNIFICANCE: Patients with temporal lobe epilepsy who experience seizures weekly or more frequently, experience a lack of aura, use levetiracetam, or take antidepressants are all at a higher risk of suicide and should be monitored closely.

Preserved Hippocampal Glucose Metabolism on 18F-FDG PET after Transplantation of Human Umbilical Cord Blood-derived Mesenchymal Stem Cells in Chronic Epileptic Rats.

Human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs) may be a promising modality for treating medial temporal lobe epilepsy. (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) is a noninvasive method for monitoring in vivo glucose metabolism. We evaluated the efficacy of hUCB-MSCs transplantation in chronic epileptic rats using FDG-PET. Rats with recurrent seizures were randomly assigned into three groups: the stem cell treatment (SCT) group received hUCB-MSCs transplantation into the right hippocampus, the sham control (ShC) group received same procedure with saline, and the positive control (PC) group consisted of treatment-negative epileptic rats. Normal rats received hUCB-MSCs transplantation acted as the negative control (NC). FDG-PET was performed at pre-treatment baseline and 1- and 8-week posttreatment. Hippocampal volume was evaluated and histological examination was done. In the SCT group, bilateral hippocampi at 8-week after transplantation showed significantly higher glucose metabolism (0.990 ± 0.032) than the ShC (0.873 ± 0.087; P < 0.001) and PC groups (0.858 ± 0.093; P < 0.001). Histological examination resulted that the transplanted hUCB-MSCs survived in the ipsilateral hippocampus and migrated to the contralateral hippocampus but did not differentiate. In spite of successful engraftment, seizure frequency among the groups was not significantly different. Transplanted hUCB-MSCs can engraft and migrate, thereby partially restoring bilateral hippocampal glucose metabolism. The results suggest encouraging effect of hUCB-MSCs on restoring epileptic networks.

Anti-NMDA Receptor Antibody Encephalitis Presenting with Unilateral Non-convulsive Status Epilepticus in a Male Patient.

Anti-N-methyl-D-aspartate (NMDA) receptor antibody encephalitis is an autoimmune antibody encephalitis with psychiatric symptoms, memory disturbances, seizures and abnormal movements. It is more common in young women. We report a young man diagnosed as anti-NMDA receptor antibody encephalitis and presenting with confusion due to non-convulsive status epilepticus involving unilateral hemisphere.

Gamma Knife radiosurgery for recurrent or residual seizures after anterior temporal lobectomy in mesial temporal lobe epilepsy patients with hippocampal sclerosis: long-term follow-up results of more than 4 years.

OBJECT: Gamma Knife radiosurgery (GKRS) has proven efficacy in the treatment of drug-resistant mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS) and is comparable to conventional resective surgery. It may be effective as an alternative treatment to reoperation after failed temporal lobe surgery in patients with MTLE-HS. The purpose of this study was to investigate the efficacy of GKRS in patients with unilateral MTLE-HS who did not achieve seizure control or had recurrent seizures after anterior temporal lobectomy (ATL). METHODS: Twelve patients (8 males; mean age 35.50 ± 9.90 years) with MTLE-HS who underwent GKRS after failed ATL (Engel Classes III-IV) were included. GKRS targets included the remnant tissue or adjacent regions of the previously performed ATL with a marginal dose of 24-25 Gy at the 50% isodose line in all patients. Final seizure outcome was assessed using Engel's modified criteria during the final 2 years preceding data analysis. A comparison between signal changes on follow-up MRI and clinical outcome was performed. RESULTS: All patients were followed up for at least 4 years with a mean duration of 6.18 ± 1.77 years (range 4-8.8 years) after GKRS. At the final assessment, 6 of 12 patients were classified as seizure free (Engel Class Ia, n = 3; Ic, n = 2; and Id, n = 1) and 6 patients were classified as not seizure free (Engel Class II, n = 1; III, n = 2; and IV, n = 3). Neither initial nor late MRI signal changes after GKRS statistically correlated with surgical outcome. Clinical seizure outcome did not differ significantly with initial or late MRI changes after GKRS. CONCLUSIONS: GKRS can be considered an alternative option when the patients with MTLE-HS who had recurrent or residual seizures after ATL refuse a second operation.

Seizure Frequencies and Number of Anti-epileptic Drugs as Risk Factors for Sudden Unexpected Death in Epilepsy.

The purpose of this study was to investigate the association between clinical variables and sudden unexpected death in epilepsy (SUDEP) and identify risk factors for SUDEP. SUDEP is one of the most frequent causes of death in patients with epilepsy. Previous studies have reported possible risk factors associated with SUDEP, but there need to be elucidated yet. The cases were 26 patients with SUDEP and three control patients were included for each case, matched for age, sex, and date of initial clinical visit. All demographic and clinical characteristics, including age, sex, disease duration, classification of epilepsy, age at seizure onset, kind and number of antiepileptic drugs, were compared between cases and controls. Seizure frequency was higher in SUDEP cases than in controls (P=0.035). Univariate analysis using conditional logistic regression showed that higher seizure frequency (odds ratio [OR]=3.1, P=0.021) and the number of antiepileptic drugs (AEDs) (OR=2.0, P=0.009) were significantly associated with SUDEP. Only the number of AEDs remained significant in multivariate analysis (OR=1.8, P=0.026). Frequent seizures and multi-drug therapy were associated with SUDEP. This may suggest that the severity of epilepsy is associated with SUDEP, regardless of the type of AED used.

Kinetics of T-cell-based assays on cerebrospinal fluid and peripheral blood mononuclear cells in patients with tuberculous meningitis.

BACKGROUND/AIMS: The goal of this study was to monitor tuberculosis (TB)-specific T-cell responses in cerebrospinal fluid-mononuclear cells (CSF-MCs) and peripheral blood mononuclear cells (PBMCs) in patients with tuberculous meningitis (TBM) over the course of anti-TB therapy. METHODS: Adult patients (≥ 16 years) with TBM admitted to Asan Medical Center, Seoul, South Korea, were prospectively enrolled between April 2008 and April 2011. Serial blood or CSF samples were collected over the course of the anti-TB therapy, and analyzed using an enzyme-linked immunosorbent spot (ELISPOT) assay. RESULTS: Serial ELISPOT assays were performed on PBMCs from 17 patients (seven definite, four probable, and six possible TBM) and CSF-MC from nine patients (all definite TBM). The median number of interferon-gamma (IFN-γ)-producing T-cells steadily increased during the first 6 months after commencement of anti-TB therapy in PBMCs. Serial CSF-MC ELISPOT assays revealed significant variability in immune responses during the first 6 weeks of anti-TB therapy, though early increases in CSF-MC ELISPOT results were associated with treatment failure or paradoxical response. CONCLUSIONS: Serial analysis of PBMCs by ELISPOT during the course of treatment was ineffective for predicting clinical response. However, increases in TB-specific IFN-γ-producing T-cells in CSF-MC during the early phase of anti-TB therapy may be predictive of clinical failure.

Comparison of clinical manifestations, outcomes and cerebrospinal fluid findings between herpes simplex type 1 and type 2 central nervous system infections in adults.

In previous reports on the viral causes of central nervous system (CNS) infections, it has been generally recognized that HSV-1 is a major cause of encephalitis, while HSV-2 is the predominant cause of aseptic meningitis in adults. To examine this matter, the clinical characteristics in the two types of HSV CNS infections were investigated. In a retrospective cohort study which included all adult patients (≥16 years) between January 1999 and December 2013 in a 2,700-bed tertiary care hospital, all the patients in whom PCR of the CSF for HSV was positive were identified. Ninety-five patients with positive CSF PCR results for HSV were included, 21 with HSV-1 and 74 with HSV-2. Many patients with HSV-1 had encephalitis (13/21, 61.9%), whereas most patients with HSV-2 had meningitis (62/74, 83.8%). However, HSV-1 and HSV-2 accounted for similar proportion of patients with HSV encephalitis (13/25, 52.0% vs. 12/25, 48.0%). Neurological sequelae were more frequent among patients with HSV-1 (9/21, 42.9% vs. 6/74, 8.1%; P = 0.001). The present study suggests that HSV-2 is not only a major cause of aseptic meningitis, but also it may cause serious manifestation as HSV-1 encephalitis in adults.

Role of low- and high-frequency oscillations in the human hippocampus for encoding environmental novelty during a spatial navigation task.

The hippocampus plays a key role in the encoding and retrieval of information related to novel environments during spatial navigation. However, the neural basis for these processes in the human hippocampus remains unknown because it is difficult to directly measure neural signals in the human hippocampus. This study investigated hippocampal neural oscillations involved in encoding novel environments during spatial navigation in a virtual environment. Seven epileptic patients with implanted intracranial hippocampal depth electrodes performed three sessions of virtual environment navigation. Each session consisted of a navigation task and a location-recall task. The navigation task consisted of eight blocks, and in each block, the participant navigated to the location of four different objects and was instructed to remember the location of the objects. After the eight blocks were completed, a location-recall task was performed for each of the four objects. Intracranial electroencephalography data were monitored during the navigation tasks. Theta (5-8 Hz) and delta (1-4 Hz) oscillations were lower in the first block (novel environment) than in the eighth block (familiar environment) of the navigation task, and significantly increased from block one to block eight. By contrast, low-gamma (31-50 Hz) oscillations were higher in the first block than in the eighth block of the navigation task, and significantly decreased from block one to block eight. Comparison of sessions with high recall performance (low error between identified and actual object location) and low recall performance revealed that high-gamma (51-100 Hz) oscillations significantly decreased from block one to block eight only in sessions with high recall performance. These findings suggest that delta, theta, and low-gamma oscillations were associated with encoding of environmental novelty and high-gamma oscillations were important for the successful encoding of environmental novelty.

Combined muscle motor and somatosensory evoked potentials for intramedullary spinal cord tumour surgery.

PURPOSE: To evaluate whether intraoperative neurophysiologic monitoring (IONM) with combined muscle motor evoked potentials (mMEPs) and somatosensory evoked potentials is useful for more aggressive and safe resection in intramedullary spinal cord tumour (IMSCT) surgery. MATERIALS AND METHODS: We reviewed data from consecutive patients who underwent surgery for IMSCT between 1998 and April 2012. The patients were divided into two groups based on whether or not IONM was applied. In the monitored group, the procedures were performed under IONM using 75% muscle amplitude decline weaning criteria. The control group was comprised of patients who underwent IMSCT surgery without IONM. The primary outcome was the rate of gross total excision of the tumour on magnetic resonance imaging at one week after surgery. The secondary outcome was the neurologic outcome based on the McCormick Grade scale. RESULTS: The two groups had similar demographics. The total gross removal tended to increase when intraoperative neurophysiologic monitoring was used, but this tendency did not reach statistical significance (76% versus 58%; univariate analysis, p=0.049; multivariate regression model, p=0.119). The serial McCormick scale score was similar between the two groups (based on repeated measure ANOVA). CONCLUSION: Our study evaluated combined IONM of trans-cranial electrical (Tce)-mMEPs and SEPs for IMSCT. During IMSCT surgery, combined Tce-mMEPs and SEPs using 75% muscle amplitude weaning criteria did not result in significant improvement in the rate of gross total excision of the tumour or neurologic outcome.

Prophylactic effect of erythropoietin injection to prevent acute mountain sickness: an open-label randomized controlled trial.

This study was performed to evaluate whether increasing hemoglobin before ascent by prophylactic erythropoietin injections prevents acute mountain sickness (AMS). This open-label, randomized, controlled trial involved 39 healthy volunteers with hemoglobin ≤ 15.5 g/dL who were divided randomly into erythropoietin (n=20) and control (n=19) groups. Epoetin alpha 10,000 IU injections were given weekly for four consecutive weeks. On day 1, and 7 days after the last injection (day 29), oxygen saturation (SaO2), and hemoglobin were measured. The subjects departed Seoul on day 30 and arrived at Annapurna base camp (ABC, 4,130 m) on day 34. AMS was diagnosed when headache and Lake Louise score (LLS) of ≥ 3 were present. Immediate descent criteria followed US Army recommendations. Two groups differ in hemoglobin levels on day 29 (15.4 ± 1.1 vs 14.2 ± 1.0 g/dL, P=0.001). At ABC, erythropoietin group had a significantly lower mean LLS, AMS incidence, and number of subjects who met immediate descent criteria. Multiple logistic regression analysis showed that SaO2<87% and control group, but not hemoglobin<15.0 g/dL, independently predicted satisfaction of immediate descent criteria. Erythropoietin-related adverse effects were not observed. In conclusion, erythropoietin may be an effective prophylaxis for AMS.(Clinical Trial Registry Number; NCT 01665781).

A pulse artifact removal method considering artifact variations in the simultaneous recording of EEG and fMRI.

A simultaneous recording of electroencephalogram (EEG) and functional magnetic resonance imaging (fMRI) can provide high spatiotemporal information of brain activity. However, a proper analysis of the EEG signals is often hindered by various artifacts. In particular, pulse artifact (PA) induced from the heartbeat of a subject interferes with reliable measurements of the EEG signal. A new PA removal method that takes into account the delay variation between the heartbeat and PA and the window size variation in PA is presented in order to improve the detection and suppression of PA in EEG signals. A PA is classified into either a normal PA or a deformed PA. Only normal PAs are averaged to generate a PA template that is used to remove PAs from the measured EEG signals. The performance of the proposed method was evaluated by simulated data and real EEG measurements from epilepsy patients. The results are compared with those from conventional methods.

Clinical features, outcomes, and cerebrospinal fluid findings in adult patients with central nervous system (CNS) infections caused by varicella-zoster virus: comparison with enterovirus CNS infections.

Varicella-zoster virus (VZV) is known to be associated with central nervous system (CNS) infections in adults. However, the clinical characteristics of VZV CNS infections are not well characterized. The aim of this study was to compare the clinical manifestations, outcomes, and cerebrospinal fluid (CSF) findings in patients with VZV CNS infections with those in patients with enterovirus (EV) CNS infections. This retrospective cohort study was performed at a 2,700-bed tertiary care hospital. Using a clinical microbiology computerized database, all adults with CSF PCR results positive for VZV or EV that were treated between January 1999 and February 2013 were identified. Thirty-eight patients with VZV CNS infection and 68 patients with EV CNS infection were included in the study. Compared with the EV group, the median age in the VZV group was higher (VZV, 35 years vs. EV, 31 years; P = 0.02), and showed a bimodal age distribution with peaks in the third and seventh decade. Encephalitis was more commonly encountered in the VZV group (VZV, 23.7% vs. EV, 4.4%; P = 0.01). The median lymphocyte percentage in the CSF (VZV, 81% vs. EV, 36%; P < 0.001) and the CSF protein level (VZV, 100 mg/dl vs. EV, 46 mg/dl; P < 0.001) were higher in the VZV group. Compared with patients with EV CNS infection, patients with VZV CNS infection developed encephalitis more often and exhibited more intense inflammatory reaction. Nevertheless, both VZV and EV CNS infections were associated with excellent long-term prognosis.