Substance use related cluster headache: A case series.

BACKGROUND: Essential oils (EOs) with pro-convulsant properties are known to cause seizures and may worsen migraine. Here we report five cases of cluster headache (CH) secondary to the usage of toothpastes containing pro-convulsant EOs. METHODS: Patients were identified from the headache clinics of three tertiary care hospitals in south India. Detailed history, examination, and brain magnetic resonance imaging were done in all patients. CH was diagnosed according to the International Classification of Headache Disorders, 3rd edition. Descriptive statistics were used to analyze data. RESULTS: We had five cases of EO-related CH (EORCH), from February 2020 to August 2021; three females and two males, with age ranging from 19 to 54 years. Three had new onset CH, while two had previous cluster attacks which had become refractory to medications for the past 1 year. The toothpastes contained EOs of camphor, eucalyptus, sage, thujone, clove, and fennel in various combinations. These toothpastes were used for a period of at least 3 months in those with new onset CH and for 12 months or more by those with chronic CH. After stopping the usage of these toothpastes, the CH attacks resolved completely within 5-10 days in all patients. In one patient we re-challenged with the same toothpaste and got the CH attack after a period of 2 months. None of the patients had recurrence of CH attacks at follow-up, ranging from 1 to 2 years. CONCLUSION: EOs with pro-convulsive properties may trigger and sustain CH. Physicians may consider inquiring about the exposure to these pro-convulsant EOs in patients with CH and may consider advising the discontinuation of products like toothpastes containing them as a possible means of CH remission.

Stimulus-Induced Narrowband Gamma Oscillations are Test-Retest Reliable in Human EEG.

Visual stimulus-induced gamma oscillations in electroencephalogram (EEG) recordings have been recently shown to be compromised in subjects with preclinical Alzheimer's Disease (AD), suggesting that gamma could be an inexpensive biomarker for AD diagnosis provided its characteristics remain consistent across multiple recordings. Previous magnetoencephalography studies in young subjects have reported consistent gamma power over recordings separated by a few weeks to months. Here, we assessed the consistency of stimulus-induced slow (20-35 Hz) and fast gamma (36-66 Hz) oscillations in subjects (n = 40) (age: 50-88 years) in EEG recordings separated by a year, and tested the consistency in the magnitude of gamma power, its temporal evolution and spectral profile. Gamma had distinct spectral/temporal characteristics across subjects, which remained consistent across recordings (average intraclass correlation of ~0.7). Alpha (8-12 Hz) and steady-state-visually evoked-potentials were also reliable. We further tested how EEG features can be used to identify 2 recordings as belonging to the same versus different subjects and found high classifier performance (AUC of ~0.89), with temporal evolution of slow gamma and spectral profile being most informative. These results suggest that EEG gamma oscillations are reliable across sessions separated over long durations and can also be a potential tool for subject identification.

Study of cerebrospinal fluid levels of lactate, lactate dehydrogenase and adenosine deaminase in the diagnosis and outcome of acute meningitis.

BACKGROUND: Meningitis is a serious clinical health issue in most developing countries. Late diagnosis and treatment result in significant morbidity and mortality. This research aims to study the utility of CSF lactate, lactate dehydrogenase (LDH), and adenosine deaminase (ADA) as diagnostic markers in acute meningitis, and to differentiate among varied aetiologies of acute meningitis and their outcomes. METHOD: A cross-sectional observational case-control study was conducted in 30 patients of suspected meningitis of varied aetiologies and 30 controls without any pre-existing neurological disorder and who underwent lumbar puncture during spinal anesthesia. A fresh CSF sample was collected in a heparinized vial following an aseptic lumbar puncture. The levels of lactate, LDH and ADA were estimated and recorded. RESULT: CSF lactate was significantly elevated in bacterial meningitis (BM) and cryptococcal meningitis, with 100% sensitivity when compared to controls. Elevated LDH was found only in BM, hence elevated LDH levels may strongly signify bacterial etiology. Significantly elevated ADA levels were noted in tuberculous meningitis. Significantly elevated levels of lactate and ADA were suggestive of slower clinical recovery and a prolonged hospital stay (p < 0.001). CONCLUSION: Estimation of CSF lactate, LDH, and ADA levels is a rapid, inexpensive and simple procedure and can play a major role in the early differentiation of bacterial, viral, tuberculous, and fungal meningitis. This would facilitate the initiation of appropriate treatment as early as possible, thereby decreasing mortality and complications.

Electrophysiological Evaluation of Audiovestibular Pathway Dysfunction in Parkinson's Disease and Its Correlates: A Case Control Study.

BACKGROUND: Parkinson's disease (PD) is associated with brainstem dysfunction causing non-motor symptoms. Vestibular evoked myogenic potential (VEMP) and brainstem auditory evoked potential (BAEP) are electrophysiological tests to assess the vestibular and auditory pathways in the brainstem. OBJECTIVES: To study the abnormalities of cervical VEMP (cVEMP) and BAEP in PD and to correlate the findings with the symptoms related to brainstem involvement. PATIENTS AND METHODS: cVEMP and BAEP were recorded in 25 PD patients and compared 25 age matched controls. The PD patients were assessed with the following clinical scales: REM Sleep Disorder Screening Questionnaire (RBD-SQ), Epworth Sleepiness Scale (ESS), mini-BESTest, Geriatric Depression Scale (GDS-15) and MMSE (Mini-mental state examination). The P13 and N23 peak latencies and the P13/N23 amplitude of cVEMP, the latencies of waves I, III and V, and the inter-peak latencies (IPL) of waves I-III, III-V and I-V of BAEP were measured. RESULTS: The PD patients showed prolonged latencies and reduced amplitude in cVEMP responses. They had abnormal BAEP in the form of prolonged absolute latencies of wave V, followed by wave III and I-V IPL with no significant difference in waves I and I-III IPL. The cVEMP abnormality was correlated directly with RBD-SQ and inversely with mini-BESTest scores. There were no correlations between cVEMP/BAEP abnormality and disease severity, GDS-15, ESS and MMSE. CONCLUSION: PD is associated with cVEMP and BAEP abnormalities that suggest auditory and vestibular pathway dysfunction in the brainstem and cVEMP correlates with the symptoms of brainstem degeneration like RBD and postural instability.

Rash Decisions in Neurology: A Case Report of Brachioradial Pruritus Secondary to Cervical Intramedullary Lesion.

Brachioradial pruritus (BRP) is an enigmatic condition often encountered by dermatologists and passed off as a benign itch. It is an "idiopathic" pruritus, presenting as severe itching on the radial aspect of the elbow. The physical examination may be unremarkable except for mild pruritic lesions. Hence, the patient is treated with local applications of sunscreens, anti-inflammatory agents, anti-histamines and steroids, most of which prove to be ineffective. Dermatomal localization of localization of pruritis has suggested cervical myeloradiculopathy as a novel aetiology and this has been elucidated in recent studies. Here we report a young man, who presented with brachioradial pruritus and was diagnosed to have a C6-7 intramedullary cervical cord lesion.

Essential oils and cluster headache: insights from two cases.

Essential oils with proconvulsive properties are known to cause seizures and may worsen migraine. Here, we report two cases of cluster headache temporally related to the use of toothpastes containing essential oils of camphor and eucalyptus.

Study of Short Latency Somatosensory and Brain Stem Auditory Evoked Potentials Patients with Acute Ischemic Stroke Involving Middle Cerebral Artery Territory.

Background The precise timings of evoked potentials in evaluating the functional outcome of stroke have remained indistinct. Few studies in the Indian context have studied the outcome of early prognosis of stroke utilizing evoked potentials. Objective The aim of this study was to determine somatosensory evoked potentials (SSEPs) and brain stem auditory evoked potentials (BAEPs), their timing and abnormalities in acute ischemic stroke involving the middle cerebral artery (MCA) territory and to correlate SSEP and BAEP with the functional outcome (National Institutes of Health Stroke Scale (NIHSS), modified Rankin scale (mRS) and Barthel's index) at 3 months. Methods MCA territory involved acute ischemic stroke patients ( n = 30) presenting consecutively to the hospital within 3 days of symptoms onset were included. Details about clinical symptoms, neurological examination, treatment, NIHSS score, mRS scores were collected at the time of admission. All patients underwent imaging of the brain and were subjected to SSEP and BAEP on two occasions, first at 1 to 3 days and second at 4 to 7 days from the onset of stroke. At 3 months of follow-up, NIHSS, mRS, and Barthel's index were recorded. Results P37 and N20 amplitude had a strong negative correlation (at 1-3 and 4-7 days) with NIHSS at admission, NIHSS at 3 months, mRS at admission, and mRS at 3 months and a significant positive correlation with Barthel's index ( p < 0.0001). BAEP wave V had a negative correlation (at 1-3 and 4-7 days) with NIHSS at admission, NIHSS at 3 months, mRS at admission, and mRS at 3 months and a positive correlation with Barthel's index ( p < 0.0001). Conclusion SSEP abnormalities recorded on days 4 to 7 from onset of stroke are more significant than those recorded within 1 to 3 days of onset of stroke; hence, the timing of 4 to 7 days after stroke onset can be considered as better for predicting functional outcome.

Deep Cerebral Venous Thrombosis-A Clinicoradiological Study.

Stroke is a common neurological emergency. Almost 80% of strokes are due to arterial occlusion. Venous thrombosis comprises less than 1-2% of all strokes. Involvement of the deep cerebral venous system is still rare and accounts for about 10.9% of all cerebral venous thromboses (CVT). CVT diagnosis is often delayed or missed, because of its variable clinical manifestations. We retrospectively (2015-18) and prospectively (2018-20) reviewed all the cases of CVT in a tertiary care center in south India. Out of a total of 52 CVT cases, 12 were due to the involvement of deep cerebral venous system. Their clinical presentation, imaging characteristics, and outcomes were assessed. The most frequent presentation was headache followed by seizures. Hyperhomocysteinemia was the most common risk factor noted. Imaging characteristics were variable, and a high index of suspicion was required for early diagnosis. All patients had favorable outcome in our study, and except one, all were treated conservatively.

Stimulus-induced gamma rhythms are weaker in human elderly with mild cognitive impairment and Alzheimer's disease.

Alzheimer's disease (AD) in elderly adds substantially to socioeconomic burden necessitating early diagnosis. While recent studies in rodent models of AD have suggested diagnostic and therapeutic value for gamma rhythms in brain, the same has not been rigorously tested in humans. In this case-control study, we recruited a large population (N = 244; 106 females) of elderly (>49 years) subjects from the community, who viewed large gratings that induced strong gamma oscillations in their electroencephalogram (EEG). These subjects were classified as healthy (N = 227), mild cognitively impaired (MCI; N = 12), or AD (N = 5) based on clinical history and Clinical Dementia Rating scores. Surprisingly, stimulus-induced gamma rhythms, but not alpha or steady-state visually evoked responses, were significantly lower in MCI/AD subjects compared to their age- and gender-matched controls. This reduction was not due to differences in eye movements or baseline power. Our results suggest that gamma could be used as a potential screening tool for MCI/AD in humans.

Alzheimer's disease is one of the most common forms of dementia, characterised by declining memory and thinking skills, and behavioural changes that worsen over time. It affects millions of people worldwide, mostly in older age, and yet early indicators of the disease are lacking. Most cases are only diagnosed once a person's brain function becomes noticeably impaired, even though known biological changes underpin the disease. Detecting Alzheimer's disease early could aid diagnosis and enable early intervention, while also improving the chances of finding treatments to halt or reverse the disease. Currently, brain function is measured by performing cognitive tests, such as remembering a set of words, imaging the brain with MRIs or CT scans, and blood or spinal fluid tests. Many of these tests can be invasive and expensive, so researchers are exploring whether measuring oscillations in the brain's electrical activity can be a non-invasive and chepaer way of testing brain function. Gamma oscillations are rhythmic signals, thought to be involved in attention and working memory. Animals used to study Alzheimer's disease have shown some abnormalities in gamma oscillations, and studies of healthy humans have also observed a decline in the strength and frequency of these oscillations with age. These findings have spurred an interest in understanding the link between gamma oscillations and AD in humans. To investigate this link, Murty et al. measured patterns of brain activity in elderly people chosen from the community using electrodes placed on their scalps (a technique called electroencephalography). These participants watched certain images previously shown to elicit gamma oscillations. Participants who were later diagnosed with early Alzheimer's disease had weaker gamma oscillations than their cognitively healthy peers in the part of the brain that processes visual images. These results build upon previous findings from animal research suggesting that gamma oscillations may be disrupted in early Alzheimer's disease. The work by Murty et al. could lead the way to new ways of diagnosing Alzheimer's disease, where early indicators are urgently needed.

A Case of Possible IgG4-Related Disease with Bilateral Optic Neuropathy and Bilateral Hippocampal Bleed.

IgG4-related disease (IgG4-RD) is a multisystem inflammatory disorder. The diagnosis requires consideration of clinical, radiographic, serological, and pathological evidence. Neurological involvement by IgG4-RD is relatively uncommon and is being increasingly recognized and reported with hypertrophic pachymeningitis and hypophysitis as the most frequent manifestations. IgG4-related involvement of brain parenchyma is rare, but isolated case reports exist. Here, we report a case of a young boy who presented to us with bilateral optic neuropathy and bilateral hippocampal bleed-related neurological involvement in a possible IgG4-RD, a rare entity.

Role of High Frequency Oscillations of Somatosensory Evoked Potentials in Deciphering Pathophysiology of Migraine.

Background Habituation deficit is considered as a neurophysiological abnormality among migraineurs in the interictal period. For clear comprehension and clarity about the mechanism underlying habituation in migraine, a sophisticated method, i.e., high frequency oscillations (HFOs) evoked potentials, have been utilized. However, studies pertaining to this in the Indian context are rare. Objective The aim of the study is to determine the utility of HFO of somatosensory evoked potential (SSEP) in deciphering the pathophysiology of migraine. Materials and Methods Sixty subjects including 30 migraineurs in the interictal period and 30 healthy controls were considered for the study. Median nerve SSEP was recorded in patients and controls by standard protocols. HFO was extracted offline using the Digital zero-phase shift band-pass filtering at 450 and 750 Hz. The early and late HFOs were determined with respect to the N20 peak and were compared between the groups. Results Of total 30 migraineurs, 18 had hemicranial headache and 12 had holocranial headache. N20 latency, P25 latency, N20 onset to peak amplitude, and N20 onset to P25 amplitude were comparable in migraineurs and controls. The intraburst frequency of early HFOs in migraineurs was significantly higher ( p = 0.04), whereas the peak-to-peak amplitude was significantly lower ( p = 0.001). Conclusion Early HFOs on SSEP represent the thalamocortical excitatory drive in migraineurs. Overall, the study reports that reduced amplitude of early HFOs in the interictal period suggest reduced thalamocortical drive in migraineurs.

COVID-19-related strokes are associated with increased mortality and morbidity: A multicenter comparative study from Bengaluru, South India.

BACKGROUND: COVID-19-related strokes are increasingly being diagnosed across the world. Knowledge about the clinical profile, imaging findings, and outcomes is still evolving. Here we describe the characteristics of a cohort of 62 COVID-19-related stroke patients from 13 hospitals, from Bangalore city, south India. OBJECTIVE: To describe the clinical profile, neuroimaging findings, interventions, and outcomes in COVID-19-related stroke patients. METHODS: This is a multicenter retrospective study of all COVID-19-related stroke patients from 13 hospitals from south India; 1st June 2020-31st August 2020. The demographic, clinical, laboratory, and neuroimaging data were collected along with treatment administered and outcomes. SARS-CoV-2 infection was confirmed in all cases by RT-PCR testing. The data obtained from the case records were entered in SPSS 25 for statistical analysis. RESULTS: During the three-month period, we had 62 COVID-19-related stroke patients, across 13 centers; 60 (97%) had ischemic strokes, while 2 (3%) had hemorrhagic strokes. The mean age of patients was 55.66 ± 13.20 years, with 34 (77.4%) males. Twenty-six percent (16/62) of patients did not have any conventional risk factors for stroke. Diabetes mellitus was seen in 54.8%, hypertension was present in 61.3%, coronary artery disease in 8%, and atrial fibrillation in 4.8%. Baseline National Institutes of Health Stroke Scale score was 12.7 ± 6.44. Stroke severity was moderate (National Institutes of Health Stroke Scale 5-15) in 27 (61.3%) patients, moderate to severe (National Institutes of Health Stroke Scale 16-20) in 13 (20.9%) patients and severe (National Institutes of Health Stroke Scale 21-42) in 11 (17.7%) patients. According to TOAST classification, 48.3% was stroke of undetermined etiology, 36.6% had large artery atherosclerosis, 10% had small vessel occlusion, and 5% had cardioembolic strokes. Three (5%) received intravenous thrombolysis with tenecteplase 0.2 mg/kg and 3 (5%) underwent mechanical thrombectomy, two endovascular and one surgical. Duration of hospital stay was 16.16 ± 6.39 days; 21% (13/62) died in hospital, while 37 (59.7%) had a modified Rankin score of 3-5 at discharge. Hypertension, atrial fibrillation, and higher baseline National Institutes of Health Stroke Scale scores were associated with increased mortality. A comparison to 111 historical controls during the non-COVID period showed a higher proportion of strokes of undetermined etiology, higher mortality, and higher morbidity in COVID-19-related stroke patients. CONCLUSION: COVID-19-related strokes are increasingly being recognized in developing countries, like India. Stroke of undetermined etiology appears to be the most common TOAST subtype of COVID-19-related strokes. COVID-19-related strokes were more severe in nature and resulted in higher mortality and morbidity. Hypertension, atrial fibrillation, and higher baseline National Institutes of Health Stroke Scale scores were associated with increased mortality.

Transcranial Doppler for Monitoring and Evaluation of Idiopathic Intracranial Hypertension.

Background Idiopathic intracranial hypertension (IIH) is a disorder of unknown origin, characterized by features of raised intracranial pressure (ICP). Existing literature is inconclusive about the role of transcranial Doppler (TCD) in the management of IIH. Objective To study the TCD changes in IIH patients, pre- and post-cerebrospinal fluid (CSF) drainage. Materials and Methods This was a prospective study, conducted between July 2017 and December 2019, in a tertiary care referral center in South India. Sixteen consecutive patients, suspected to have IIH, underwent magnetic resonance imaging ofthe brain, a baseline TCD, and lumbar puncture with CSF drainage and pressure monitoring. Post-CSF drainage, TCD was repeated and mean flow velocities, peak systolic velocities, end-diastolic velocities, and pulsatility index (PI), in the middle cerebral artery (MCA), vertebral artery, and basilar artery (BA) were noted. Thirteen patients had elevated CSF pressure, and fulfilled the diagnostic criteria for IIH. These patients were included in the final analysis and pre- and post-CSF drainage TCD blood flow velocities and PI were compared. Results The mean age of study participants was 29.92 ± 6.92 years. There was a significant reduction in the cerebral flow velocities in bilateral MCA, after CSF drainage and normalization of ICP. Flow velocities in posterior circulation and PI in MCA, PCA, and BA showed an insignificant reduction. Two patients, who did not show any reduction in flow velocities after CSF drainage, developed optic atrophy on follow-up. Conclusion TCD-derived systolic blood flow velocities can be used in the management and follow-up of patients with IIH.

Gamma oscillations weaken with age in healthy elderly in human EEG.

Gamma rhythms (~20-70 â€‹Hz) are abnormal in mental disorders such as autism and schizophrenia in humans, and Alzheimer's disease (AD) models in rodents. However, the effect of normal aging on these oscillations is unknown, especially for elderly subjects in whom AD is most prevalent. In a first large-scale (236 subjects; 104 females) electroencephalogram (EEG) study on gamma oscillations in elderly subjects (aged 50-88 years), we presented full-screen visual Cartesian gratings that induced two distinct gamma oscillations (slow: 20-34 â€‹Hz and fast: 36-66 â€‹Hz). Power decreased with age for gamma, but not alpha (8-12 â€‹Hz). Reduction was more salient for fast gamma than slow. Center frequency also decreased with age for both gamma rhythms. The results were independent of microsaccades, pupillary reactivity to stimulus, and variations in power spectral density with age. Steady-state visual evoked potentials (SSVEPs) at 32 â€‹Hz also reduced with age. These results are crucial for developing gamma/SSVEP-based biomarkers of cognitive decline in elderly.

Efficacy of Neuroprotective Drugs in Acute Ischemic Stroke: Is It Helpful?

Background Out of several neuroprotective drugs (NPDs) studied in animals and humans, four NPDs (citicoline, edaravone, cerebrolysin, and minocycline) have been found to have beneficial effects in acute ischemic stroke (AIS). Objective The purpose is to evaluate the efficacy of citicoline, edaravone, minocycline, and cerebrolysin compared with placebo in patients with middle cerebral artery (MCA) territory AIS. Materials and Methods This was a prospective, single center, single-blinded, and hospital-based study. One hundred patients with MCA territory AIS with 20 patients in each group including control group were included. Barthel index (BI), National Institute of Health Stroke Scale (NIHSS) score, and modified Rankin Scale score were recorded at admission, at day 11 and after 90 days. Results The mean NIHSS score was significantly lesser at day 11 and after 90 days in citicoline, edaravone, and cerebrolysin group in comparison with placebo. Similarly, the mean BI score was significantly higher at day 11 and after 90 days in citicoline, edaravone, and cerebrolysin group in comparison with placebo. In minocycline group, there was no significant change in the NIHSS score and BI score at day 11 and after 90 days. Conclusion There was significant improvement in the functional outcome of patients with AIS involving MCA territory at 90 days receiving citicoline, edaravone, and cerebrolysin. However, minocycline did not offer the same efficacy as compared with other neuroprotective agents.

Longitudinally Extensive Transverse Myelitis with Aquaporin-4 Antibody Positivity in Renal Cell Carcinoma: Rare Occurrence.

The occurrence of longitudinally extensive transverse myelitis (LETM) in an elderly patient should evoke search for underlying systemic malignancy. Intramedullary spinal cord metastases and paraneoplastic myelopathy are the most common etiology for LETM in patients with systemic malignancy. The occurrence of LETM in association with renal cell carcinoma with aquaporin-4 (AQP4) antibody positivity has not been reported. We report an elderly woman who presented with acute paraplegia and was diagnosed as having LETM with AQP4 positivity and renal cell carcinoma.