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Introduction: Global hippocampal atrophy has been repeatedly reported in patients with Parkinson's disease (PD). However, there is limited literature on the differential involvement of hippocampal subfields among PD motor subtypes. This study aimed to investigate hippocampal subfield alterations in patients with PD based on their predominant symptoms., Method: We enrolled 31 PD patients with the tremor-dominant (TD) subtype, 27 PD patients with postural instability and gait disturbance-dominant (PIGD) subtype, and 40 healthy controls (HCs). All participants underwent high-spatial-resolution T1-weighted magnetic resonance imaging. The volume of hippocampal subfields was measured using FreeSurfer software, compared across groups, and correlated with clinical features., Results: We found volumetric reductions in the hippocampal subfield in both patient subtypes compared to HCs, which were more pronounced in the PIGD subtype. The PIGD subtype had accelerated age-related alterations in the hippocampus compared to the TD subtype. Bilateral hippocampal volumes were positively associated with cognitive performance levels, but not with disease severity and duration in patients., Conclusions: Alterations in the hippocampal subfields of patients with PD differed based on their predominant symptoms. These findings are of relevance for understanding the pathophysiology of the increased risk of cognitive impairment in PIGD., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Background: Dual-task is a challenge for Parkinson's disease patients with postural instability and gait disorders (PD-PIGD)., Objective: This study investigated clinical, cognitive and functional brain correlates of dual-task deficits in PD-PIGD patients using quantitative gait analysis, neuropsychological evaluations and functional MRI (fMRI)., Methods: Twenty-three PD-PIGD patients performed a clinical assessment of gait/balance abilities. Single and dual-task Timed-Up-and-Go tests were monitored using an optoelectronic system to study turning velocity. Patients underwent executive-attentive function evaluation and two fMRI tasks: motor-task (foot anti-phase movements), and dual-task (foot anti-phase movements while counting backwards by threes starting from 100). Twenty-three healthy subjects underwent neuropsychological and fMRI assessments., Results: Dual-task in PD-PIGD patients resulted in worse gait performance, particularly during turning. Performing the dual-task relative to the motor-fMRI task, healthy subjects showed widespread increased recruitment of sensorimotor, cognitive and cerebellar areas and reduced activity of inferior frontal and supramarginal gyri, while PD-PIGD patients showed increased recruitment of inferior frontal gyrus and supplementary motor area and reduced activity of primary motor, supramarginal and caudate areas. Dual-task gait alterations in patients correlated with balance and executive deficits and with altered dual-task fMRI brain activity of frontal areas., Conclusions: This study suggested the correlation between dual-task gait difficulties, postural instability and executive dysfunction in PD-PIGD patients. FMRI results suggest that an optimized recruitment of motor and cognitive networks is associated with a better dual-task performance in PD-PIGD. Future studies should evaluate the effect of specific gait/balance and dual-task trainings to improve gait parameters and optimize brain functional activity during dual-tasks., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Background and Purpose: Vestibular symptoms are common after concussion. Vestibular Ocular Motor Screening identifies vestibular impairment, including postconcussive visual motion sensitivity, though the underlying functional brain alterations are not defined. We hypothesized that alterations in multisensory processing are responsible for postconcussive visual motion sensitivity, are detectable on fMRI, and correlate with symptom severity., Materials and Methods: Twelve patients with subacute postconcussive visual motion sensitivity and 10 healthy control subjects underwent vestibular testing and a novel fMRI visual-vestibular paradigm including 30-second "neutral" or "provocative" videos. The presence of symptoms/intensity was rated immediately after each video. fMRI group-level analysis was performed for a "provocative-neutral" condition. Z -statistic images were nonparametrically thresholded using clusters determined by Z > 2.3 and a corrected cluster significance threshold of P = .05. Symptoms assessed on Vestibular Ocular Motor Screening were correlated with fMRI mean parameter estimates using Pearson correlation coefficients., Results: Subjects with postconcussive visual motion sensitivity had significantly more Vestibular Ocular Motor Screening abnormalities and increased symptoms while viewing provocative videos. While robust mean activation in the primary and secondary visual areas, the parietal lobe, parietoinsular vestibular cortex, and cingulate gyrus was seen in both groups, selective increased activation was seen in subjects with postconcussive visual motion sensitivity in the primary vestibular/adjacent cortex and inferior frontal gyrus, which are putative multisensory visual-vestibular processing centers. Moderate-to-strong correlations were found between Vestibular Ocular Motor Screening scores and fMRI activation in the left frontal eye field, left middle temporal visual area, and right posterior hippocampus., Conclusions: Increased fMRI brain activation in visual-vestibular multisensory processing regions is selectively seen in patients with postconcussive visual motion sensitivity and is correlated with Vestibular Ocular Motor Screening symptom severity, suggesting that increased visual input weighting into the vestibular network may underlie postconcussive visual motion sensitivity., (© 2021 by American Journal of Neuroradiology.)

Ulnar artery revascularization in hypothenar hammer syndrome has repeatedly been shown to reduce ischaemic symptoms, however with varying graft patency percentages. This study prospectively assesses the effect of revascularization surgery with a vein graft using validated questionnaires in seven patients. The Disabilities of the Arm, Shoulder and Hand (DASH) and the Cold Intolerance Symptom Severity (CISS) questionnaires have been used to compare the preoperative and postoperative functionality and cold intolerance. All patients showed improvement in either functionality, or cold intolerance, or both from disabled to nearly normalized levels and resumed their occupation at final follow-up (mean of 28 months). Strikingly this was also the case in a patient with graft stenosis. Patients with the highest preoperative questionnaire scores showed most postoperative improvement. In conclusion, revascularization surgery seems to improve the symptomatology irrespective of graft patency. Questionnaires can be a valuable contribution to quantify and to follow the symptomatology in hypothenar hammer syndrome., Competing Interests: Declaration of Competing Interest The authors declared no potential conflicts of interest with respect to the research, authorship and/or publication of this article., (Copyright © 2020 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.)

Background: Postural control is affected after incomplete spinal cord injury (iSCI) due to sensory and motor impairments. Any alteration in the availability of sensory information can challenge postural stability in this population and may lead to a variety of adaptive movement coordination patterns. Hence, identifying the underlying impairments and changes to movement coordination patterns is necessary for effective rehabilitation post-iSCI. This study aims to compare the postural control strategy between iSCI and able-bodied populations by quantifying the trunk-leg movement coordination under conditions that affects sensory information., Methods: 13 individuals with iSCI and 14 aged-matched able-bodied individuals performed quiet standing on hard and foam surfaces with eyes open and closed. We used mean Magnitude-Squared Coherence between trunk-leg accelerations measured by accelerometers placed over the sacrum and tibia., Results: We observed a similar ankle strategy at lower frequencies (f ≤ 1.0 Hz) between populations. However, we observed a decreased ability post-iSCI in adapting inter-segment coordination changing from ankle strategy to ankle-hip strategy at higher frequencies (f > 1.0 Hz). Moreover, utilizing the ankle-hip strategy at higher frequencies was challenged when somatosensory input was distorted, whereas depriving visual information did not affect balance strategy., Conclusion: Trunk-leg movement coordination assessment showed sensitivity, discriminatory ability, and excellent test-retest reliability to identify changes in balance control strategy post-iSCI and due to altered sensory inputs. Trunk-leg movement coordination assessment using wearable sensors can be used for objective outcome evaluation of rehabilitative interventions on postural control post-iSCI.

Background: A concept of sensory tracts in the spinal cord has been established in relation to a dorsolateral pathway which is located in the posterior part of the lateral column and conveys the deep sense., Methods: The clinical status at onset, neurological symptoms, and magnetic resonance imaging (MRI) findings in 13 patients of spinal cord infarction were studied., Results: The clinical status was acute in 11 patients and subacute in 2 patients. Palsy of the extremities was noted in 11 patients. Segmental sensory disturbance was shown in all patients. One patient showed disturbance of all senses and paraplegia, which indicated transverse myelopathy. In the other 12 patients, 11 patients showed impairment of pain sense although joint position sense was preserved, excluding 1 patient whose sensory disturbance showed dysesthesia alone. In these 11 patients, soft touch and vibration senses were impaired in 7 patients. Abnormality of spinal cord MRI was detected 7 patients. The lesions were located in the cervical cord in 3 patients, cervical to thoracic cord in 1 patient, and thoracic cord in 3 patients., Conclusions: In the 11 patients in whom pain sense was impaired and joint position sense was preserved, involvement of the anterior spinal cord artery (ASCA) was the mainstay. Impairment of vibration sense was accompanied in 7 patients in patients of ASCA infarction. It was speculated that impairment of vibration sense can occur in patients with ASCA infarction whose ischemia spread to the dorsolateral pathway in the posterior part of the lateral column., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Autonomous sensory meridian response (ASMR) is a perceptual phenomenon in which specific auditory and/or visual stimuli consistently elicit tingling sensations on the neck, scalp, and shoulders, as well as a positive and relaxed emotional state. The "ASMR triggers" that initiate these responses generally consist of soft sounds (e.g., whispering), repetitive noises (e.g., tapping sounds), or videos of people performing socially intimate acts (e.g., watching someone brush her hair). Despite being a relatively common phenomenon, little is known about the neural substrates of ASMR. In the current research, resting-state functional magnetic resonance imaging (fMRI) was used to examine whether ASMR was associated with atypical patterns of functional connectivity. Seventeen individuals with ASMR and 17 matched control participants underwent an anatomical MRI scan and a resting-state fMRI scan. An independent components analysis was used to identify the default mode, salience, central executive, sensorimotor, and visual networks. An analysis of variance with group (ASMR vs. control) as a between-subjects variable was performed to contrast the functional connectivity of each of these networks. The results demonstrated that ASMR was associated with reduced functional connectivity in the salience and visual networks, and with atypical patterns of connectivity in the default mode, central executive, and sensorimotor networks.

Introduction: We investigated the imaging counterpart of two functional domains (ocular motor dysfunction and postural instability) in progressive supranuclear palsy (PSP) patients classified according to the new clinical diagnostic criteria., Methods: Forty-eight patients with probable PSP-Richardson's syndrome (PSP-RS), 30 with probable PSP-parkinsonism (PSP-P), 37 with Parkinson's disease (PD), and 38 controls were enrolled. For each functional domain, PSP patients were stratified by two certainty levels: vertical supranuclear gaze palsy (O1) and slowness of vertical saccades (O2) for ocular motor dysfunction; early unprovoked falls and tendency to fall on the pull-test for postural instability. Voxel-based morphometry (VBM), whole-brain fractional anisotropy (FA) and MR planimetric measurements were analysed and compared across patient groups., Results: O1 was present in 64%, and O2 in 36% of all PSP patients. All PSP-RS patients showed early unprovoked falls. TBSS whole-brain analysis revealed that superior cerebellar peduncles (SCPs) were the only structures with significantly lower FA values in PSP-RS compared with PSP-P patients. PSP/O1 patients had lower FA values in midbrain than PSP/O2 patients. By contrast, VBM revealed no differences in grey matter volume between PSP patient groups. MR Planimetric measurements confirmed atrophy of midbrain and SCPs, in line with DTI findings., Conclusions: Our study demonstrates that SCPs were significantly more damaged in patients with PSP-RS in comparison with PSP-P patients, thus suggesting the role of SCPs in developing postural instability. Midbrain damage was less severe in O2 than in O1 patients, suggesting that the degree of vertical ocular dysfunction reflects the severity of midbrain atrophy., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Aim: Our aim was to characterize the sensory processing outcome following neonatal arterial ischemic stroke (NAIS) and identify neuroanatomical correlates of abnormal sensory processing., Method: We evaluated children with NAIS longitudinally at 12 months, 18 months, and/or 30 months in areas of cognitive, motor, and language development. We gathered sensory processing data using the Sensory Profile-2 Caregiver Questionnaire. These data were analyzed against early magnetic resonance imaging using a voxel-based approach., Results: Eighteen children (10 males, 8 females) with NAIS were evaluated longitudinally, of which six exhibited atypical sensory processing. Children with sensory processing deficits had lower overall developmental scores in motor, cognitive, and language domains. Neuroanatomical correlates were identified in the posterior periventricular white matter extending superiorly into the supramarginal gyrus, and inferiorly into the fusiform and inferior temporal gyri., Interpretation: Our results provide new evidence that children with NAIS may experience difficulty processing sensory information, which is most likely associated with injuries in the posterior periventricular white matter, supramarginal gyrus, fusiform gyrus, and posterior thalamic radiation., What This Paper Adds: Atypical sensory processing is common in children with neonatal arterial ischemic stroke (NAIS). NAIS territories in sensory areas were correlated with atypical sensory processing behaviors. Children with NAIS may benefit from early interventions targeted toward sensory processing. Future research mapping NAIS injuries using early magnetic resonance imaging may predict long-term outcomes., (© 2018 Mac Keith Press.)

Background and Purpose: Postural instability gait disorder is a motor subtype of Parkinson disease associated with predominant gait dysfunction. We investigated the periventricular white matter comprising longitudinal, thalamic, and callosal fibers using diffusion tensor MR Imaging and examined clinical correlates in a cohort of patients with Parkinson disease and postural instability gait disorder and healthy controls., Materials and Methods: All subjects underwent the Tinetti Gait and Balance Assessment and brain MR imaging. The DTI indices (fractional anisotropy, mean diffusivity, axial diffusivity, and radial diffusivity) from ROIs dropped over the superior and inferior longitudinal fasciculi, inferior fronto-occipital fasciculus, anterior thalamic radiation, anterior and posterior limbs of the internal capsule, and the genu and body of corpus callosum were evaluated., Results: Our findings showed that the superior longitudinal fasciculus, inferior longitudinal fasciculus, inferior fronto-occipital fasciculus, anterior thalamic radiation, genu of the corpus callosum, and body of the corpus callosum are more affected in postural instability gait disorder than in those with Parkinson disease or healthy controls, with more group differences among the longitudinal fibers. Only the callosal fibers differentiated the postural instability gait disorder and Parkinson disease groups. DTI measures in the superior longitudinal fasciculus, frontostriatal fibers (anterior thalamic radiation, anterior limb of the internal capsule), and genu of the corpus callosum fibers correlated with clinical gait severity., Conclusions: Findings from this case-control cohort lend further evidence to the role of extranigral pathology and, specifically, the periventricular fibers in the pathophysiology of postural instability gait disorder., (© 2019 by American Journal of Neuroradiology.)

The "sensory processing disorder" (SPD) refers to brain's inability to organize sensory input for appropriate use. In this study, we determined the diffusion tensor imaging (DTI) microstructural and connectivity correlates of SPD, and apply machine learning algorithms for identification of children with SPD based on DTI/tractography metrics. A total of 44 children with SPD and 41 typically developing children (TDC) were prospectively recruited and scanned. In addition to fractional anisotropy (FA), mean diffusivity (MD), and radial diffusivity (RD), we applied probabilistic tractography to generate edge density (ED) and track density (TD) from DTI maps. For identification of children with SPD, accurate classification rates from a combination of DTI microstructural (FA, MD, AD, and RD), connectivity (TD) and connectomic (ED) metrics with different machine learning algorithms - including naïve Bayes, random forest, support vector machine, and neural networks - were determined. In voxel-wise analysis, children with SPD had lower FA, ED, and TD but higher MD and RD compared to TDC - predominantly in posterior white matter tracts including posterior corona radiata, posterior thalamic radiation, and posterior body and splenium of corpus callosum. In stepwise penalized logistic regression, the only independent variable distinguishing children with SPD from TDC was the average TD in the splenium (p < 0.001). Among different combinations of machine learning algorithms and DTI/connectivity metrics, random forest models using tract-based TD yielded the highest accuracy in classification of SPD - 77.5% accuracy, 73.8% sensitivity, and 81.6% specificity. Our findings demonstrate impaired microstructural and connectivity/connectomic integrity in children with SPD, predominantly in posterior white matter tracts, and with reduced TD of the splenium of corpus callosum as the most distinctive pattern. Applying machine learning algorithms, these connectivity metrics can be used to devise novel imaging biomarkers for neurodevelopmental disorders., (Copyright © 2019. Published by Elsevier Inc.)

Dizziness, postural instability, and ataxia are among the most debilitating symptoms of multiple sclerosis (MS), reflecting, in large part, dysfunctional integration of visual, somatosensory, and vestibular sensory cues. However, the role of MS-related supratentorial lesions in producing such symptoms is poorly understood. In this study, motor control test (MCT) and dynamic sensory organization test (SOT) scores of 58 MS patients were compared to those of 72 healthy controls; correlations were determined between the MS scores of 49 patients and lesion volumes within 26 brain regions. Depending upon platform excursion direction and magnitude, MCT latencies, which were longer in MS patients than controls (p < 0.0001), were correlated with lesion volumes in the cortex, medial frontal lobes, temporal lobes, and parietal opercula (r's ranging from 0.20 to 0.39). SOT test scores were also impacted by MS and correlated with lesions in these same brain regions as well as within the superior frontal lobe (r's ranging from - 0.28 to - 0.40). The strongest and most consistent correlations occurred for the most challenging tasks in which incongruent visual and proprioceptive feedback were given. This study demonstrates that supratentorial lesion volumes are associated with quantitative balance measures in MS, in accord with the concept that balance relies upon highly convergent and multimodal neural pathways involving the skin, muscles, joints, eyes, and vestibular system.

Competing Interests: Competing interests: None declared.

Background and Purpose: Sensory neuronopathy is a cardinal feature of cerebellar ataxia neuropathy vestibular areflexia syndrome (CANVAS). Having observed that two patients with CANVAS had small median and ulnar nerves on ultrasound, we set out to examine this finding systematically in a cohort of patients with CANVAS, and compare them with both healthy controls and a cohort of patients with axonal neuropathy. We have previously reported preliminary findings in seven of these patients with CANVAS and seven healthy controls., Methods: We compared the ultrasound cross-sectional area of median, ulnar, sural and tibial nerves of 14 patients with CANVAS with 14 healthy controls and 14 age- and gender-matched patients with acquired primarily axonal neuropathy. We also compared the individual nerve cross-sectional areas of patients with CANVAS and neuropathy with the reference values of our laboratory control population., Results: The nerve cross-sectional area of patients with CANVAS was smaller than that of both the healthy controls and the neuropathy controls, with highly significant differences at most sites (P < 0.001). Conversely, the nerve cross-sectional areas in the upper limb were larger in neuropathy controls than healthy controls (P < 0.05). On individual analysis, the ultrasound abnormality was sufficiently characteristic to be detected in all but one patient with CANVAS., Discussion: Small nerves in CANVAS probably reflect nerve thinning from loss of axons due to ganglion cell loss. This is distinct from the ultrasound findings in axonal neuropathy, in which nerve size was either normal or enlarged. Our findings indicate a diagnostic role for ultrasound in CANVAS sensory neuronopathy and in differentiating neuronopathy from neuropathy., (© 2018 EAN.)

One in two survivors experience impairment in touch sensation after stroke. The nature of this impairment is likely associated with changes associated with the functional somatosensory network of the brain; however few studies have examined this. In particular, the impact of lesioned hemisphere has not been investigated. We examined resting state functional connectivity in 28 stroke survivors, 14 with left hemisphere and 14 with right hemisphere lesion, and 14 healthy controls. Contra-lesional hands showed significantly decreased touch discrimination. Whole brain functional connectivity (FC) data was extracted from four seed regions, i.e. primary (S1) and secondary (S2) somatosensory cortices in both hemispheres. Whole brain FC maps and Laterality Indices (LI) were calculated for subgroups. Inter-hemispheric FC was greater in healthy controls compared to the combined stroke cohort from the left S1 seed and bilateral S2 seeds. The left lesion subgroup showed decreased FC, relative to controls, from left ipsi-lesional S1 to contra-lesional S1 and to distributed temporal, occipital and parietal regions. In comparison, the right lesion group showed decreased connectivity from contra-lesional left S1 and bilateral S2 to ipsi-lesional parietal operculum (S2), and to occipital and temporal regions. The right lesion group also showed increased intra-hemispheric FC from ipsi-lesional right S1 to inferior parietal regions compared to controls. In comparison to the left lesion group, those with right lesion showed greater intra-hemispheric connectivity from left S1 to left parietal and occipital regions and from right S1 to right angular and parietal regions. Laterality Indices were significantly greater for stroke subgroups relative to matched controls for contra-lesional S1 (left lesion group) and contra-lesional S2 (both groups). We provide evidence of altered functional connectivity within the somatosensory network, across both hemispheres, and to other networks in stroke survivors with impaired touch sensation. Hemisphere of lesion was associated with different patterns of altered functional connectivity within the somatosensory network and with related function was associated with different patterns of altered functional connectivity within the somatosensory network and with related functional networks.

Background: Atlanto-occipital dislocation (AOD) is the most uncommon form of traumatic cervical spine injury. The majority of patients die before reaching higher-level care, and only a small percentage of patients with AOD survive the initial injury after receiving tertiary care. As such, there is a paucity of evidence-based management guidelines for treating this condition. Halo vest fixation has been a proposed method for interim stability while these patients undergo medical optimization for surgical intervention. There have been several reports of worsening AOD after halo placement. Reverse Trendelenburg position after halo fixation has been previously described to aid in the reduction of AOD, as well as concomitant atlantoaxial dislocation by gravitational downward force., Case Description: In this series we present 2 cases of obese patients (body mass index >30) with AOD treated by halo fixation that had increased distraction after head of bed elevation., Conclusion: Our theorized mechanism for this phenomenon is due to the downward pull of subaxial forces secondary to a large body habitus., (Published by Elsevier Inc.)

Objectives: Balance and gait deficits can persist after mild traumatic brain injury (TBI), yet an understanding of the underlying neural mechanism remains limited. The purpose of this study was to investigate differences in attention network modulation in patients with and without balance impairments 2-8 weeks following mild TBI., Methods: Using functional magnetic resonance imaging, we compared activity and functional connectivity of cognitive brain regions of the default mode, central-executive and salience networks during a 2-back working memory task in participants with mild TBI and balance impairments (n = 7, age 47 ± 15 years) or no balance impairments (n = 7, age 47 ± 15 years)., Results: We first identified greater activation in the lateral occipital cortex in the balance impaired group. Second, we observed stronger connectivity of left pre-supplementary motor cortex in the balance impaired group during the working memory task, which was related to decreased activation of regions within the salience and central executive networks and greater suppression of the default mode network., Conclusions: Results suggest a link between impaired balance and modulation of cognitive resources in patients in mTBI. Findings also highlight the potential importance of moving beyond traditional balance assessments towards an integrative assessment of cognition and balance in this population.

Rationale: Cheiro-Oral syndrome (COS) is a pure sensory deficit confined to the perioral area and ipsilateral distal fingers or hand. Owing to relatively minor clinical findings and various presentations in different cases, the insidious and severe illness it implies may be overlooked at acute settings., Patient Concerns: A 70-year-old man with history of hypertension and type II diabetes mellitus under regular medication control came to our emergency department with chief complaint of sudden onset of right perioral region and right upper limb numbness. General physical and neurological examinations were normal except for subtle hypoesthesia to light touch, and pinprick in the right corner of mouth and right forearm to distal fingers., Diagnoses: Routine blood analysis was all in normal range including white blood cell count, hemocrit platelet, renal and liver function, and electrolytes such as sodium and potassium. Noncontrast brain computed tomography showed abnormal high-attenuation collection in the left thalamus., Intervention: Follow-up computed tomography showed absorption of the hemorrhage after strict control of his blood pressure., Outcomes: The patient was discharged 7 days later from our hospital with stable condition., Lessons: We demonstrated type I COS associated with thalamic hemorrhage to highlight the neurological implication of COS. It is crucial for emergency clinicians to recognize the symptoms and promptly order a neuroimaging study to exclude large infarction/hemorrhage, which would deeply affect the disposition and following treatment of the patient., (Copyright © 2017 The Authors. Published by Wolters Kluwer Health, Inc. All rights reserved.)

A pure sensory neuronopathy (also referred to as a sensory ganglionopathy) is one of a handful of classical neurological paraneoplastic syndromes. Current guidelines recommend that in cases of sensory neuronopathy, a search for an underlying malignancy be pursued for up to 4 years. We report the case of a 52-year-old woman with a sensory neuronopathy who was eventually diagnosed with a cholangiocarcinoma 6 years after the onset of her disease. A CT fluorodeoxyglucose positron emission tomography (FDG-PET) scan performed 18 and 24 months after disease onset failed to identify an underlying neoplasm. Immunomodulatory treatment with corticosteroids, intravenous immunoglobulins and plasma exchange were ineffective. Investigations for Sjogren's disease were negative. A third FDG-PET performed 6 years after symptom onset identified a cholangiocarcinoma, which was confirmed histologically following open resection. Since the tumour was removed, our patient's condition has not progressed, but there has been no improvement and she remains severely disabled., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

Background: The presence of vertebral fractures affect variations in the termination level of conus medullaris (TLCM) and alter neurological findings. However, few studies have examined association between vertebral fractures, TLCM, and neurological findings. Thus, we herein studied the number and severity of vertebral fractures, TLCM, and neurological findings to clarify the mechanism of neurological deterioration in patients with vertebral fractures., Methods: A total of 411 patients who underwent computed tomographic myelography were classified into those with (group F, n = 73) and those without vertebral fractures (group C, n = 338). We assessed correlations between TLCM and age, height, and gender in group C, differences in TLCM between groups F and C, and correlations between TLCM, and the number and severity score of fractures. Neurological evaluations were performed for the patellar tendon reflex (PTR), muscle weakness, sensory disturbance, and bladder contraction disorders., Results: TLCM was most commonly located at the L1 vertebral body in group C and did not significantly differ with age, height, or gender. TLCM was most commonly located at L2 vertebral body in group F. TLCM was more caudally located in group F (P < 0.01). Additionally, there was a significant difference between TLCM and number of fractures, and the severity score of fractures (both P < 0.01). Twenty-three patients showed neurological deterioration by vertebral fractures. Some patients with T12 vertebral fracture showed hyperreflexia of PTR. Serious bladder contraction disorders were seen in patients with compression at close range of TLCM., Conclusion: We confirmed that vertebral fractures altered location of the TLCM, thus altering potential neurological symptoms. Moreover, there were correlations of the TLCM with the number and severity score of vertebral fractures. Spine surgeons should be cognizant of the relationship between TLCM, level of compressive lesion, and neurological findings to avoid the wrong level in spine surgery and unexpected neurological deteriorations after surgery.

Background: Medial medullary infarction (MMI) is a rare ischemic stroke. Frequency of each neurological finding in MMI was different in each study., Methods: We retrospectively evaluated the medical records of patients with cerebral infarction who were admitted between March 1998 and October 2015. Patients in our study were diagnosed as having MMI by magnetic resonance image examination., Results: Of 2727 patients with ischemic stroke, 27 patients (20 males and 7 females) had MMI. The MMI was complicated by infarcts located in the pons (n = 6), cerebellum (n = 2), and lateral medulla (n = 1). One patient had bilateral MMI. Large-artery atherosclerosis was the most common etiology. Motor weakness of the extremities was the most common neurological finding. Diminished contralateral superficial sensation was more common than diminished contralateral vibratory sensation, and these 2 types of sensory disturbance were often complicated. The patients with large MMI significantly more often accompanied diminished touch (P = .003), pain (P = .017), and vibratory (P = .019) sensation. Facial weakness was shown more common contralateral to the infarcts than ipsilateral (n = 8 contralateral, n = 1 ipsilateral). Lingual palsy was also more common contralateral to the lesions (n = 3 contralateral, n = 1 ipsilateral). One patient alone fulfilled the classical Dejerine triad., Conclusions: In MMI, motor weakness of extremities was commonly shown, and complication of diminished sensations indicated the large infarcts. As for facial weakness and lingual palsy, the supranuclear type was more prominent than the infranuclear type., (Copyright © 2017 National Stroke Association. Published by Elsevier Inc. All rights reserved.)

Competing Interests: We have read and understood BMJ policy on declaration of interests and declare no competing interests.

Patients with schizophrenia show specific abnormalities in visual perception, and patients with bipolar disorder may have related perceptual deficits. During tasks that highlight perceptual dysfunction, patients with schizophrenia show abnormal activity in visual brain areas, including the lateral occipital complex (LOC) and early retinotopic cortex. It is unclear whether the anatomical structure of those visual areas is atypical in schizophrenia and bipolar disorder. In members of those two patient groups and healthy controls, we localized LOC and early retinotopic cortex individually for each participant using functional magnetic resonance imaging (MRI), then measured the thickness of those regions of interest using structural MRI scans. In both regions, patients with schizophrenia had the thinnest cortex, controls had the thickest cortex, and bipolar patients had intermediate cortical thickness. A control region, motor cortex, did not show this pattern of group differences. The thickness of each visual region of interest was significantly correlated with performance on a visual object masking task, but only in schizophrenia patients. These findings suggest an anatomical substrate for visual processing abnormalities that have been found with both neural and behavioral measures in schizophrenia and other severe mental illnesses., (© The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.)

Most studies on sensory extinction have focused on selected patients with subacute and chronic right hemisphere lesions. In studies conducted on acute stroke patients, risk factors and time course were not evaluated. Our aim was to determine the prevalence, risk factors, and time course of sensory extinction in the acute stroke setting. Consecutive patients with acute stroke were tested for tactile, visual, auditory, and auditory-tactile cross-modal extinction, as well as for peripersonal visuospatial neglect (PVN). Tests were repeated at 2, 7, 15, 30, and 90 days after initial examination. A multivariable logistic regression analysis was performed to test the association between sensory extinction and demographic and clinical risk factors. Seventy-three patients (38.4% women) were recruited: 64 with ischemic stroke and nine with haemorrhagic stroke. Mean age was 62.3 years (95% CI 58.8-65.7), mean NIHSS score was 1.6 (95% CI 1.2-2.1), and mean time to first examination was 4.1 days (95% CI 3.5-4.8). The overall prevalence of all subtypes of sensory extinction was 13.7% (95% CI 6.8-23.8). Tactile extinction was the most frequent subtype with a prevalence of 8.2% (95% CI 3.1-17.0). No extinction was found beyond 15 days after the first examination. After adjustment for age, sex, lesion side, type of stroke, time to first examination and stroke severity, a lesion volume ≥2 mL (adjusted OR = 38.88, p = 0.04), and presence of PVN (adjusted OR = 24.27, p = 0.04) were independent predictors of sensory extinction. The insula, the putamen, and the pallidum were the brain regions most frequently involved in patients with sensory extinction. Extinction is a rare and transient phenomenon in patients with minor stroke. The presence of PVN and lesion volume ≥2 mL are independent predictors of sensory extinction in acute stroke.

Objective: The salience network, an intrinsic brain network thought to modulate attention to internal versus external stimuli, has been consistently found to be atypical in autism spectrum disorders (ASD). However, little is known about how this altered resting-state connectivity relates to brain activity during information processing, which has important implications for understanding sensory overresponsivity (SOR), a common and impairing condition in ASD related to difficulty downregulating brain responses to sensory stimuli. This study examined how SOR in youth with ASD relates to atypical salience network connectivity and whether these atypicalities are associated with abnormal brain response to basic sensory information., Method: Functional magnetic resonance imaging was used to examine how parent-rated SOR symptoms related to salience network connectivity in 61 youth (aged 8-17 years; 28 with ASD and 33 IQ-matched typically developing youth). Correlations between resting-state salience network connectivity and brain response to mildly aversive tactile and auditory stimuli were examined., Results: SOR in youth with ASD was related to increased resting-state functional connectivity between salience network nodes and brain regions implicated in primary sensory processing and attention. Furthermore, the strength of this connectivity at rest was related to the extent of brain activity in response to auditory and tactile stimuli., Conclusion: Results support an association between intrinsic brain connectivity and specific atypical brain responses during information processing. In addition, findings suggest that basic sensory information is overly salient to individuals with SOR, leading to overattribution of attention to this information. Implications for intervention include incorporating sensory coping strategies into social interventions for individuals with SOR., (Copyright © 2016 American Academy of Child and Adolescent Psychiatry. Published by Elsevier Inc. All rights reserved.)

Background: Insight into the neural mechanisms of postural instability and gait disorder (PIGD) and tremor dominant (TD) subtypes in Parkinson's disease (PD) is indispensable for generating pathophysiology hypotheses underlying this phenotyping. This cross-sectional study aimed to gain insight in specific and brain-wide functional connectivity (FC) and its correlation with motor deterioration and preservation in PD subtypes., Methods: 68 PD patients classified as PIGD (n = 41), TD (n = 19) or indeterminate (n = 8) and 19 age-matched controls underwent resting-state fMRI while 'off' medication to assess FC between regions of interest (ROIs) in the motor and fronto-parietal network and on a whole-brain level using a parcellated template. FC alterations were correlated with quantitative behavioral measures., Results: ROI-analyses showed decreased FC between the caudate and putamen in PIGD compared to TD. This hypo-connectivity was correlated with behavioral impairment. In contrast, TD-specific hyper-connectivity between motor cortical areas and the inferior parietal lobule correlated with less behavioral impairment, suggesting compensatory mechanisms. Both subgroups showed hyper-connectivity between the left supplementary motor area and pedunculopontine nucleus, whereas PIGD-specific right lateralized hyper-connectivity was shown between this nucleus and the premotor cortex. Whole-brain analyses revealed 65% hypo-connectivity and 35% hyper-connectivity in PIGD compared to TD. TD also revealed primarily hypo-connectivity compared to controls, but had more pronounced hyper-connectivity involving temporo-occipital areas., Conclusion: This multilevel analysis showed differential connectivity alterations in large scale neural networks and between motor and cognitive control areas that related to behavioral heterogeneity in PD, underscoring the classic TD-PIGD phenotypical classification., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

This chapter focuses on one of the most common types of neurologic disorders: altered walking. Walking impairment often reflects disease of the neurologic structures mediating gait, balance or, most often, both. These structures are distributed along the neuraxis. For this reason, this chapter is introduced by a brief description of the neurobiologic underpinning of walking, stressing information that is critical for imaging, namely, the anatomic representation of gait and balance mechanisms. This background is essential not only in order to direct the relevant imaging tools to the regions more likely to be affected but also to interpret correctly imaging findings that may not be related to the walking deficit object of clinical study. The chapter closes with a discussion on how to image some of the most frequent etiologies causing gait or balance impairment. However, it focuses on syndromes not already discussed in other chapters of this volume, such as Parkinson's disease and other movement disorders, already discussed in Chapter 48, or cerebellar ataxia, in Chapter 23, in the previous volume. As regards vascular disease, the spastic hemiplegia most characteristic of brain disease needs little discussion, while the less well-understood effects of microvascular disease are extensively reviewed here, together with the imaging approach., (© 2016 Elsevier B.V. All rights reserved.)

Background: Case reports are presented on four Veterans, aged 29-46 years, who complained of chronic dizziness and/or postural instability following blast exposures. Two of the four individuals were diagnosed with mild traumatic brain injury and three of the four were exposed to multiple blasts. Comprehensive vestibular, balance, gait, audiometry and neuroimaging procedures were used to characterize their injuries., Case Report: Vestibular assessment included videonystagmography, rotary chair and cervical and ocular vestibular evoked myogenic potentials. Balance and gait testing included the sensory organization test, preferred gait speed and the dynamic gait index. Audiometric studies included pure tone audiometry and middle-ear measurements. Neuroimaging procedures included high resolution structural magnetic resonance imaging, susceptibility-weighted imaging and diffusion-tensor imaging., Findings: Based on the neuroimaging and vestibular and balance test results, it was found that all individuals had diffuse axonal injuries and all had one or more micro-hemorrhages or vascular anomalies. Three of the four individuals had abnormal vestibular function, all had abnormally slow walking speeds and two had abnormal gait and balance dysfunction., Conclusion: The use of contemporary neuroimaging studies in conjunction with comprehensive vestibular and balance assessment provided a better understanding of the pathophysiology and pathoanatomy of dizziness following blast exposures than standard vestibular and balance testing alone.

Background: The purpose of this study was to use panoramic radiographic findings to predict postsurgical sensory impairment following the extraction of impacted mandibular third molars., Methods: There were 120 patients enrolled in this study (55 male and 65 female). A total of 120 impacted mandibular third molars were included due to the proximity between the inferior alveolar nerve (IAN) canal and the roots of the impacted third molar on the panoramic radiograph. Seven radiographic signs were the predictor variables: (1) darkening of the root(s); (2) interruption of the radiopaque line of the inferior alveolar canal; (3) diversion of the inferior alveolar canal; (4) dark and bifid apex; (5) deflection of the root(s); (6) narrowing of the inferior alveolar canal; and (7) narrowing of the root(s). The outcome variable was the postoperative IAN sensory impairment. The retrospective cohort study model was used, and univariable and bivariable statistics was computed with the statistically significant level at p ≤ 0.05., Results: Three of the radiographic signs were statistically associated with IAN sensory impairment (p<0.05). They include: (1) interruption of the radiopaque line [sensitivity = 0.92, specificity = 0.45, positive predictive value (PPV) = 0.17, negative predictive value (NPV) = 0.02]; (2) diversion of the IAN canal (sensitivity = 0.77, specificity = 0.84, PPV = 0.37, NPV = 0.03); and (3) narrowing of the IAN canal (sensitivity = 0.69, specificity = 0.65, PPV = 0.19, NPV = 0.05). However, the other four radiographic signs, namely darkening of the root(s), dark and bifid apex, deflection of the root(s), and narrowing of the root(s), were not statistically associated with IAN sensory impairment (p>0.05)., Conclusion: There are three radiographic signs: (1) interruption of the radiopaque line; (2) diversion of the IAN canal; and (3) narrowing of the IAN canal. These signs are valuable in presurgical evaluation of the risk of postoperative sensory impairment after surgical removal of impacted mandibular third molar., (Copyright © 2015. Published by Elsevier Taiwan.)

Background and Purpose: Globus sensation is common and difficult to treat. The purpose of our study was to compare the diagnostic and therapeutic efficacy of barium esophagram and neck CT in patients with isolated globus sensation, to determine which of these modalities should be preferred in the evaluation of this condition., Materials and Methods: We retrospectively identified patients presenting with isolated globus sensation from January 1, 2005, to December 31, 2012, who underwent neck CT or barium esophagram. We calculated the proportion of patients with abnormal findings, tabulated the nature of the abnormality, and reviewed the medical records to determine whether imaging changed management., Results: One hundred forty-eight neck CTs and 104 barium esophagrams were included. Five (3.4%) patients with neck CTs and 4 (3.9%) with barium esophagrams demonstrated significant findings related to the history of globus sensation. Of these, 1 (0.7%) neck CT and 1 (1.0%) barium esophagram resulted in a change in clinical management., Conclusions: Imaging evaluation of the patient with uncomplicated globus sensation is unlikely to identify clinically significant imaging findings and is very unlikely to result in a change in clinical management, with a combined therapeutic efficacy of 0.8%. Thus, the routine use of imaging in the evaluation of patients with globus sensation cannot be recommended.

Background: Intramuscular adipose tissue (IMAT) of the lower extremity is a strong negative predictor of mobility function. Variability in temporal gait factors is another important predictor of mobility function. The purpose of this study was to examine the relationships between IMAT in the hip and thigh muscles, balance, and temporal gait variability in older adults., Methods: Forty-eight healthy community dwelling older adults (74 +/- 1 year) underwent a CT scan to quantify IMAT in the gluteus maximus (Gmax), gluteus medius/minimus (Gmed/min), hamstrings, vastus lateralis, and adductor muscles. Temporal Gait measures were collected on a GAITRite walkway and gait variability was determined by calculating intraindividual standard deviations. Individuals were divided by tertiles of temporal gait variability into categories of high, medium, and low variability. Differences in the IMAT of the hip abductors were calculated for those with high and low gait variability and partial correlations for gait variability and all muscle composition measures were determined for all variables with normalized gait speed as a covariate., Results: Gmed/min IMAT was greater in those with higher gait variability compared to those with lower gait variability (p<0.05). Gmed/min IMAT was related to stride width variability (r=0.30, p<0.05). Gmax IMAT was also related to time variability of swing (r=0.42), stance (r=0.26), double limb support (r=0.43), double support loading (r=0.44), and double support unloading (r=0.50) (all p<0.05)., Conclusion: Increased IMAT in the proximal hip muscles, particularly the hip abductors, was associated with increased gait variability and poorer balance. These findings may have implications for the assessment and treatment of balance and falls such that interventions for enhancing balance and mobility among older individuals should take into account the importance of gluteal muscle composition.

Study Design: Prospective radiographic study., Objective: To investigate the feasibility of controlling quality of reconstructed sagittal balance for sagittal imbalance., Summary of Background Data: Patients with sagittal imbalance cannot walk or stand erect without overwork of musculature because of compromised biomechanical advantage. The result is muscle fatigue and activity-related pain. During reconstructive surgery, restoration of optimal sagittal balance is crucial for obtaining satisfactory clinical results. However, there is no way to control quality of reconstructed sagittal balance before or during surgery., Methods: A method was developed to determine the lumbosacral curve in a way that theoretically would bring sagittal balance to an ideal state by calculation and simulation for each patient before surgery and then template rods of the curve and a blueprint were made accordingly for operative procedures. Ninety-four consecutive patients with sagittal imbalance due to lumbar kyphosis were treated for intractable pain and then followed up for a mean of 4.3 years. Radiographs were analyzed before surgery, 2 months after surgery, and at most recent follow-up., Results: The mean estimated values of L1-S1 lordosis, sacral inclination angle, sacrofemoral distance, and distribution of L1-S1 lordosis at the closing-opening wedge osteotomy site and L4-S1 segments were 30.8°, 24.6°, 0 mm, 16.1% (-5°), and 62% (-19°), respectively. The mean reconstructed values were 41.1°, 23.3°, 3.9 mm, 41% (-17°), and 46% (-19°), respectively. There were significant differences between estimated and reconstructed values of L1-S1 lordosis and the percentage of distributions; however, there was no significant difference between the estimated and reconstructed magnitude of L4-S1 lordosis, sacral inclination angle, and sacrofemoral distance. A properly oriented pelvis can be brought nearly directly above the hip axis. The mean sagittal global balance, represented by the distance between the vertical line through the hip axis and sacral promontory, improved from 61.4 mm before surgery to 3.9 mm 2 months after surgery, and 1.3 mm at final follow-up. Normal sagittal global balance was reconstructed and maintained. The mean sagittal spinal balance measured as the horizontal distance between the C7 sagittal plumb line and the posterior superior corner of S1 improved from 97.4 mm before surgery to 11 mm 2 months after surgery. However, there was significant loss of sagittal spinal balance to 25.4 mm at the fi nal visit. Normal sagittal spinal balance was reconstructed and appeared to be maintained. The magnitude of T1-T12 kyphosis compensated from 13° before surgery to 25.2° 2 months after surgery and 34.5° at fi nal follow-up., Conclusions: Quality control of the reconstructed sagittal balance for sagittal imbalance is possible. Correctly orienting the pelvis, reconstructed by the restoration of enough L1-S1 lordosis with adequate distribution at L4-S1 segments, is a matter of critical importance for optimizing reconstructed sagittal balance. The correctly oriented pelvis can be determined before surgery. Preventing junctional fracture and persistent rehabilitation of surgically injured lumbar extensor musculature are crucial for maintaining the reconstructed sagittal balance.

Object: Variation in the number of lumbar vertebrae occurs in a small portion of the population. Either the fifth lumbar vertebra shows assimilation to the sacrum or the first sacral vertebra shows a lumbar configuration, resulting in 4 or 6 lumbar vertebrae, respectively. Etiologically, lumbar nerve root syndrome is diagnosed by comparing the anatomical level of the disc herniation to the compressed nerve root and to the pattern of the peripheral sensory and motor deficit. In case of a variation in the number of lumbar vertebrae, defining the lumbar nerve roots becomes difficult. Variations in the number of lumbar vertebrae make the landmarks (the twelfth rib and the first sacral vertebra) unreliable clues to define the nerve roots. The allocation of the clinically damaged segment to the spinal disorder seen in imaging studies is essential for differential diagnosis and spine surgery., Methods: A retrospective study was conducted of clinical, electrophysiological, and imaging data among inpatients over a period of 21 months. Eight patients who had isolated monosegmental discogenic nerve root compression and a variation in the number of lumbar vertebrae were selected., Results: Seven patients presented with 6 lumbar vertebrae, and 1 patient presented with 4 lumbar vertebrae and disc herniation on 1 of the 2 caudal levels. Compression of the second-to-last nerve root in patients with 6 lumbar vertebrae resulted either in clinical L-5 or S-1 syndrome, or a combination of both. Compression of the last caudal nerve root resulted in a clinical S-1 nerve root syndrome., Conclusions: The findings suggest that the dermatomyotomal supply of the lumbosacral nerve roots can vary in patients with a variation in the number of lumbar vertebrae, and a meticulous clinical, radiological, and electrophysiological examination is essential.

Purpose: Standard magnetic resonance imaging (MRI) does not depict the true extent of tumour cell invasion in gliomas. We investigated the feasibility of advanced imaging methods, i.e. diffusion tensor imaging (DTI), fibre tracking and O-(2-[(18)F]-fluoroethyl)-L: -tyrosine ((18)F-FET) PET, for the detection of tumour invasion into white matter structures not visible in routine MRI., Methods: DTI and fibre tracking was performed on ten patients with gliomas, WHO grades II-IV. Five patients experienced preoperative sensorimotor deficits. The ratio of fractional anisotropy (FA) between the ipsilateral and contralateral pyramidal tract was calculated. Twenty-one stereotactic biopsies from five patients were histopathologically evaluated for the absolute numbers and percentages of tumour cells. (18)F-FET PET scans were performed and the bilateral ratio [ipsilateral-to-contralateral ratio (ICR)] of (18)F-FET-uptake was calculated for both cross-sections of pyramidal tracts and biopsy sites., Results: The FA ratio within the pyramidal tract was lower in patients with sensorimotor deficits (0.61-1.06) compared with the FA ratio in patients without sensorimotor deficits (0.92-1.06). In patients with preoperative sensorimotor deficits, we found a significantly (p = 0.028) higher ICR of (18)F-FET uptake (1.01-1.59) than in patients without any deficits (0.96-1.08). The ICR of (18)F-FET-uptake showed a strong correlation (r = 0.696, p = 0.001) with the absolute number of tumour cells and a moderate correlation (r = 0.535, p = 0.012) with the percentage of tumour cells., Conclusions: Our data show an association between preoperative sensorimotor deficits, increased (18)F-FET uptake and decreased FA ratio in the pyramidal tract. We demonstrated a correlation between tumour invasion and (18)F-FET uptake. These findings may help to distinguish between edema versus tumour-associated neurological deficits and could prevent the destruction of important structures, like the pyramidal tract, during tumour operations by allowing more precise preoperative planning.

Neural plasticity induced by stroke can mediate positive outcomes, such as recovery of function, but can also result in the formation of abnormal connections with negative consequences for perception and cognition. In three experiments using blood-oxygen level dependent (BOLD) functional magnetic resonance imaging, we examined the neural substrates of acquired auditory-tactile synesthesia, in which certain sounds can produce an intense somatosensory tingling sensation in a patient with a thalamic lesion. Compared with nine normal controls, the first experiment showed that the patient had a threefold greater BOLD response to sounds in the parietal operculum, the location of secondary somatosensory cortex. We hypothesized that this abnormal opercular activity might be the neural substrate of the patient's synesthesia. Supporting this hypothesis, the second experiment demonstrated that sounds that produced no somatosensation did not evoke a BOLD response in the operculum, while sounds that produced strong somatosensations evoked large BOLD responses. These abnormal responses may have resulted from plasticity induced by the loss of somatosensory inputs. Consistent with this idea, in the third experiment, BOLD responses to somatosensory stimulation were significantly weaker in the patient's operculum than in normal controls. These experiments demonstrate a double dissociation in the patient's secondary somatosensory cortex (increased responses to auditory stimulation and decreased responses to somatosensory stimulation), and suggest both that stroke-induced plasticity can result in abnormal connections between sensory modalities that are normally separate, and that synesthesia can be caused by inappropriate connections between nearby cortical territories.

We describe a partial sensory and motor block of the ipsilateral lower limb after interscalene infusion. After and injection of 20 mL of ropivacaine through the needle, the catheter was advanced 5 cm, and an infusion of ropivacaine 0.2% 5 mL/h commenced. Six hours later, the patient reported a left sensory and motor hemisyndrome, which resolved after the infusion was discontinued. Cervical computed tomography showed the tip of the catheter close to the intervertebral foramen at the C7-T1 level and several intravertebral paramedullar air bubbles. We conclude that the neurological symptoms were caused by an injection of local anesthetic via an interscalene catheter placed in proximity to the epidural space. To avoid this complication, we recommend advancing the catheter no more than 2-3 cm and performing frequent neurological evaluation of patients.

In 139 patients, 260 consecutive retrogasserian glycerol rhizotomies for trigeminal neuralgia were retrospectively analyzed regarding technical surgical difficulties and immediate and early complications. Technical obstacles occurred in 47.3%. In 21 cases (8.1%), the surgical procedure had to be interrupted due to circumstances such as vasovagal reactions, cardiac arrest, or difficulties to find the trigeminal cistern. Complications or side effects, being either transient or persistent, occurred in 67.3%. In the vast majority, those unwanted effects were related to mild sensory deficits. However, in 28.1% the complications were other than mild affection of facial sensibility. These slightly graver complications included labial herpes (3.8%), anesthesia dolorosa (0.8%), moderate or severe affection of sensibility (18.8%), dysesthesia (22.7%), chemical meningitis (1.5%) and infectious meningitis (1.5%). In 5 patients (1.9%) hearing was affected. In one of them, this condition was also brought about by tinnitus, and in another patient a preexisting tinnitus deteriorated. Although the frequency of surgical difficulties was high, the success of the glycerol injection was hampered only in a minor number of procedures. The frequency of complications and side effects was high, but they were mostly mild due to their nature and non-disabling for the patient. However, long-lasting disabling side effects occurred, and this should not be neglected when informing patients preoperatively. The surgical training needed to perform the procedure is stressed, and the use of prophylactic antibiotics when accidentally penetrating the oral bucca is recommended. We consider retrogasserian glycerol rhizotomy to be a good surgical option for patients with trigeminal neuralgia not suitable for microvascular decompression and when pharmacological therapy is not sufficient or is not tolerated., (Copyright 2002 S. Karger AG, Basel)