Ｐａｔｔｅｒｎ ｒｅｖｅｒｓａｌ ＶＥＰにて視神経炎が示唆されたリンパ球性下垂体炎の１例

2. Visual evoked potentials in the diagnosis of multiple sclerosis

The aim of this neurophysiological study was to retrospectively analyze visual evoked potentials (VEPs) acquired during an examination for diagnosing optic nerve involvement in patients with Lyme neuroborreliosis (LNB). Attention was focused on LNB patients with peripheral facial palsy (PFP) and optic nerve involvement. A total of 241 Czech patients were classified as having probable/definite LNB (193/48); of these, 57 were younger than 40 years, with a median age of 26.3 years, and 184 were older than 40 years, with a median age of 58.8 years. All patients underwent pattern-reversal (PVEP) and motion-onset (MVEP) VEP examinations. Abnormal VEP results were observed in 150/241 patients and were noted more often in patients over 40 years (p = 0.008). Muscle/joint problems and paresthesia were observed to be significantly more common in patients older than 40 years (p = 0.002, p = 0.030), in contrast to headache and decreased visual acuity, which were seen more often in patients younger than 40 years (p = 0.001, p = 0.033). Peripheral facial palsy was diagnosed in 26/241 LNB patients. Among patients with PFP, VEP peak times above the laboratory limit was observed in 22 (84.6%) individuals. Monitoring of patients with PFP and pathological VEP showed that the adjustment of visual system function occurred in half of the patients in one to more years, in contrast to faster recovery from peripheral facial palsy within months in most patients. In LNB patients, VEP helps to increase sensitivity of an early diagnostic process.

We report a 38-year-old female suffering from bilateral optic neuritis with lymphocytic adenohypophysitis. The initial symptom of the 38-year-old-female was diabetes insipidus. Magnetic resonance imaging showed swollen pituitary stalk and disappearance of the T1 shortening of the neurohypophysis. Immunological tests showed that the serum anterior pituitary antibody was positive. These findings suggested lymphocystic adenohypophysitis. Bilateral optic neuritis also occurred and the pattern visual evoked cortical potential (VECP) demonstrated increased P100 peak latency and reduction of amplitude. After steroid pulse therapy, the visual acuity and field improved and the pattern VECP became normal. Temporal hemianopia was not noted. A direct infiltration of the inflammatory change in the pituitary gland or some autoimmune problem was considered as a cause of the optic neuritis. In contrast to the VECPs of multiple sclerosis patients, the prolonged peak latency of pattern VECPs of this case were shortened in accordance with the recovery of visual acuity.

Visual evoked potentials in children and adolescence with neurofibromatosis type 1

To study the quantitative and qualitative differences of visual evoked potential (VEP) in monocular visual impairment after different parts of visual pathway injury. A total of 91 subjects with monocular visual impairment caused by trauma were selected and divided into intraocular refractive media-injury group (eyeball injury group for short), optic nerve injury group, central nervous system injury and intracranial combined injury group according to the injury cause and anatomical segment. Pattern Reversal visual evoked potential (PR-VEP) P100 peak time and amplitude, Flash visual evoked potential (F-VEP) P2 peak time and amplitude were recorded respectively. SPSS 26.0 software was used to analyze the differences of quantitative (peak time and amplitude) and qualitative indexes (spatial frequency sweep-VEP acuity threshold, and abnormal waveform category and frequency) of the four groups. Compared with healthy eyes, the PR-VEP P100 waveforms of the intraocular eyeball injury group and the F-VEP P2 waveforms of the optic nerve group showed significant differences in prolonged peak time and decreased amplitude in injured eyes (P<0.05). The PR-VEP amplitudes of healthy eyes were lower than those of injured eyes at multiple spatial frequencies in central nervous system injury group and intracranial combined injury group (P<0.05).The amplitude of PR-VEP in patients with visual impairment involving central injury was lower than that in patients with eye injury at multiple spatial frequencies. The frequency of VEP P waveforms reaching the threshold of the intraocular injury group and the optic nerve injury group were siginificantly different from the intracranial combined injury group, respectively(P<0.008 3), and the frequency of abnormal reduction of VEP amplitude of threshold were significantly different from the central nervous system injury group, respectively(P<0.008 3). VEP can distinguish central injury from peripheral injury, eyeball injury from nerve injury in peripheral injury, but cannot distinguish simple intracranial injury from complex injury, which provides basic data and basis for further research on the location of visual impairment injury.

The purpose of this study was to assess chiasmal misrouting in a cohort of children with albinism with no nystagmus using hemifield visual evoked potentials (VEP) measures. Methods: Monocular VEPs were recorded and analyzed from three electrodes (O1, Oz, and O2 referred to Fz) from 16 children with albinism without nystagmus. Pattern reversal (full field and hemifield stimulation), full field pattern appearance and flash stimuli were used to evoke VEPs for each eye. Results: The amplitude of the pattern reversal VEPs to stimulation of the hemifield corresponding to the crossing pathways were as expected significantly larger than those to the non-crossing in each eye ((right eye p = 0.000004), (left eye p = 0.001)). Pattern reversal VEPs recorded from the left hemisphere were also larger than those from the right and most evident when comparing the crossing pathways of each eye (p = 0.004). Conclusions: This study has demonstrated electrophysiological differences in visual pathway function of the left and right hemisphere in subjects with albinism like that previously described in controls. Nasal field stimulation activated crossing and non-crossing pathways in patients with albinism and as a result, nasal hemifield VEPs in albinism are less lateralized compared to what is found in normal subjects.

Background and Aims Visual evoked potentials (VEPs) assess the integrity of the visual pathways from the optic nerve to the occipital cortex. Optic disc cupping and visual field loss have been associated with prolongation of latency of VEP in primary open angle glaucoma (POAG). Methods Pattern reversal and flash VEP tests were done in consenting 20 primary open angle glaucoma eyes and 40 normal control eyes. Results In POAG cases, the refractive error [3.51 ± 1.88 versus 1.88 ± 1.11, D, p = 0.001], cup-disc ratio in percent [66.00 ± 16.98 versus 28.50 ± 5.80, p = 0.001], intraocular pressure [19.55 ± 2.08 versus 11.65 ± 1.64, mmHg, p = 0.001], and automated visual field pattern standard deviation [4.13 ± 6.96 versus 1.64 ± 0.45, dB, p = 0.001] were significantly more than in control. The visual acuity [0.41 ± 0.29 versus 1.00 ± 0.00, p = 0.001], foveal visual sensitivity [25.92 ± 6.88 versus 33.48 ± 1.75, dB, p = 0.001], and automated visual field mean deviation [−9.63 ± 10.58 versus 0.07 ± 1.54, dB, p = 0.001] were significantly less in cases than in control. Among VEP variables, pattern reversal latency N145 [149.00 ± 15.75 versus 137.52 ± 15.20, ms, p = 0.011], flash amplitude N75 [2.18 ± .57 versus 1.47 ± .38, μV, p = 0.001], and flash amplitude N145 [1.99 ± .39 versus 1.43 ± .38, μV, p = 0.001] were increased in cases. The pattern reversal amplitude N75 [1.97 ± .35 versus 2.47 ± .58, μV, p = 0.001], amplitude P100 [3.09 ± .46 versus 6.07 ± 1.44, μV, p = 0.001], and amplitude N145 [2.21 ± .58 versus 4.45 ± 1.99, μV, p = 0.001] were decreased in cases. Conclusions POAG caused glaucomatous damage to optic pathway.

Lymphocytic hypophysitis (LYH) is a rare autoimmune inflammatory disorder of the pituitary gland that can involve either the anterior or posterior lobe, or both. In some cases, it initially presents with isolated central diabetes insipidus (CDI) and later progresses to anterior pituitary hormone deficiencies. However, longitudinal descriptions of this progression are limited. A 66-year-old woman presented with dry mouth, polydipsia, and polyuria. Magnetic resonance imaging (MRI) revealed symmetrical pituitary enlargement with loss of the posterior pituitary bright spot, thickening of the pituitary stalk, and homogeneous contrast enhancement of both the pituitary stalk and posterior pituitary. Hormonal testing confirmed preserved anterior pituitary function but impaired vasopressin secretion, consistent with CDI secondary to lymphocytic posterior hypophysitis. During follow-up, serum prolactin levels gradually increased, while cortisol and thyroid hormone levels declined. Approximately one year after the onset of symptoms, MRI showed further pituitary stalk enlargement, and stimulation tests demonstrated diminished responses of adrenocorticotropic hormone, cortisol, and luteinizing hormone. Combined anterior pituitary hormone deficiencies were diagnosed, and replacement therapy with hydrocortisone and levothyroxine was initiated, resulting in symptomatic improvement. Serial hormonal and radiologic assessments revealed the progression from isolated posterior pituitary dysfunction to combined anterior pituitary failure, accompanied by pituitary stalk enlargement.These findings suggest that both mechanical compression resulting from pituitary stalk enlargement and direct inflammatory extension from the posterior pituitary may contribute to the development of anterior pituitary dysfunction. This case was considered to represent LYH, showing possible dynamic changes in pituitary function and morphology over time. Administration of pharmacologic-dose steroids or pituitary biopsy should be considered if further progressive pituitary enlargement or new mass effects, such as headache or visual disturbance, become evident.

The effect of spectral filters on VEP and alpha-wave responses

Objective: To evaluate the clinical characteristics and etiologies of central diabetes insipidus (CDI). Methods: The clinical data of 230 patients with CDI in the Department of Endocrinology of Chinese PLA General Hospital from 2008 June to 2014 December were collected and analyzed retrospectively. Results: The three most common causes of CDI were idiopathic CDI, lymphocytic hypophysitis and intracranial germ cell tumors. Among all the CDI, the idiopathic CDI accounted for 37.48%. There were significant differences in age onset and gender distribution among the different causes of CDI. The patients with intracranial germ cell tumors [age of onset(19.2±10.2) years] were younger than the other types of CDI. Germ cell tumors patients were more common in male, and lymphocytic hypophysitis patients were more common in female. The most frequent abnormality of anterior pituitary in patients with CDI was growth hormone deficiency, followed by hypogonadism, adrenal insufficiency and hypothyroidism. The dysfunction of thyroid axis and adrenal axis in patients with germ cell tumor was more common than those in patients with idiopathic and lymphocytic hypophysitis. Conclusions: The most common causes of central diabetes insipidus were idiopathic CDI, lymphocytic hypophysitis and intracranial germ cell tumors. There were differences in age of onset, gender distribution and abnormal production of anterior pituitary hormones among all causes of CDI patients.

Background. The differential diagnosis of pituitary stalk lesions is broad and includes neoplastic, inflammatory, infectious, and congenital disorders. Lymphocytic infundibuloneurohypophysitis (LIN) has been identified as an etiology of transient pituitary stalk enlargement leading to permanent central diabetes insipidus (DI). We present a case of transient isolated pituitary stalk enlargement complicated by both central DI and hypopituitarism. Case. A 65-year-old male presented to hospital with polyuria, polydipsia, nausea and vomiting, and a 20 lb. unintentional weight loss over three weeks. Hypernatremia (149 mM, 133-142) and inappropriately dilute urine (180 mOsm/kg) were noted on admission. Treatment with desmopressin resulted in prompt resolution of polyuria and hypertonicity. MRI was notable for nodular thickening of the pituitary stalk and loss of the posterior pituitary bright spot on T-1 weighted images, and lumbar puncture yielded clear fluid with mild lymphocytic pleocytosis, no malignant cells, and unremarkable angiotensin converting enzyme level. Evaluation of anterior pituitary function revealed secondary adrenal insufficiency, secondary hypothyroidism, secondary hypogonadism, impaired somatotroph function, and mild hyperprolactinemia (16.2 ng/mL, 3.6-13.2). The patient recovered to baseline weight and well-being on treatment with hydrocortisone, thyroxine, and intramuscular testosterone. He declined biopsy in favor of serial imaging of the pituitary stalk. Over the course of 18 months, radiographic changes in the pituitary stalk resolved, though DI and anterior pituitary deficits persist. Conclusion. Radiographic lesions confined to the pituitary stalk present a significant diagnostic challenge because biopsies are difficult and potentially injurious to patients. Diagnosis is based mostly on clinical evaluation and imaging. Epidemiological data are sparse; out of 150,045 head MRI studies at Mayo Clinic from 1987-2006, 2,700 were reviewed due to mention of “pituitary stalk” or “infundibulum” and 152 were found to have a pituitary stalk abnormality. LIN has been demonstrated on biopsy in patients with central DI and reversible pituitary stalk enlargement. In a series of 17 adult patients with LIN, central DI was persistent despite improvement in pituitary stalk abnormalities, but anterior pituitary function was preserved. A more recent series of nine children with central DI and apparent LIN followed for a mean of five years found six patients with resolution of pituitary stalk abnormalities; central DI persisted in all patients, and only one experienced loss of anterior pituitary function. Though unusual, this case illustrates that LIN may be complicated by permanent hypopituitarism in addition to central DI, possibly by injury from undetectable extension of pituitary stalk inflammation to the pituitary gland or hypothalamus.

The effects of carbamazepine (CBZ) and sodium valproate (SV) monotherapy on visual evoked potentials (VEP) were studied in 18 epileptic children receiving CBZ and nine epileptic children receiving SV. Pattern reversal VEP were determined before the administration of antiepileptic drugs (AED) and 1 year later during which time the patients had received AED. The VEP amplitude showed no consistent changes after 1 year of CBZ and SV therapy, but VEP P-100 latencies were significantly prolonged after 1 year of CBZ therapy. We conclude that CBZ causes a slowing down of central impulse conduction and that VEP is useful to evaluate the effects of AED within the central nervous system.

Purpose:Visual evoked potentials (VEP) are used to determine the function of visual pathway from the optic nerve to visual cortex. Various factors may affect VEP response, viz., technical and environmental. The aim of this study is to obtain the normative value of VEP latency and amplitude parameters in adulthood in Indonesia, as well as the relationship of height, weight, body mass index (BMI), head circumference, and visual acuity with the variety of latency and amplitude values of VEP parameters.Methods:It is a cross-sectional study on 120 healthy subjects consisting of 60 males and 60 females between 18 and 65 years old. Height, weight, BMI, head circumference, and visual acuity were measured and continued with VEP examination using a 26′ checkerboard pattern on the left and right eyes alternately. All data were collected and analyzed with the Shapiro–Wilk test using statistical software R version 3.5.2.Results:Mean value of P100 latency (interocular latency) of left and right eye were 104.6 ± 3.4 ms and 104.1 ± 3.4 ms, respectively, as well as 9.8 ± 4.7 μV and 10.3 ± 5.4 μV for the amplitude. There was no significant difference between the male and female group, as well as on the age group. Female significantly exhibited a higher P100 amplitude than male. The greater the age, the lower amplitude of P100 significantly.Conclusion:Gender and age do not affect the P100 latency value but only affect P100 amplitude. Height, weight, BMI, head circumference, and visual acuity also do not affect the P100 latency and amplitude.

A study of brainstem auditory evoked potentials (BAEPs) and pattern reversal visual evoked potentials (VEPs), recorded in intercritical phase, was carried out in 20 subjects (10 suffering from common migraine and 10 suffering from vertebrobasilar TIA) in order to obtain a comparative evaluation of cortical-subcortical functions. The data we obtained demonstrate the presence of BAEPs alterations in patients with previous vertebrobasilar TIA: no abnormalities were found in the migraine group. VEPs parameters are normal in both groups. Our data show that the study of the so-called "stimulus-related" potentials, such as BAEPs and pattern reversal VEPs, is useful in evaluating the damage produced by any noxa, while it cannot clearly emphasize individual factors predisposing to a specific pathology, as the absence of specific alterations in migraine patients demonstrates.

Serial pattern evoked potential recording in a case of toxic optic neuropathy due to ethambutol