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Azimi A, Bonakdaran S, Heravian J, Layegh P, Yazdani N, Alborzi M. Pattern visual evoked potential in hypothyroid patients. Doc Ophthalmol 2019; 138:77-84. [PMID: 30680490 DOI: 10.1007/s10633-019-09670-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Accepted: 01/07/2019] [Indexed: 10/27/2022]
Abstract
PURPOSE To investigate the functional integrity of visual pathway in hypothyroid patients by pattern visual evoked potential (PVEP). METHODS We enrolled 36 female patients with history of hypothyroidism (18 overt and 18 subclinical) aged 20 to 60 years and 36 healthy women of similar age (control group). All subjects had a complete ophthalmic examination. For VEP testing, subjects were exposed to checks subtending a visual angle of 15 and 60 min of arc. RESULTS For the 15 min of arc check size, the mean P100 latency was significantly delayed (113 milliseconds (ms)) and amplitude significantly reduced (9.2 microvolts (µv)) in the hypothyroidism group compared with controls (109.6 ms and 11.6 µv, respectively). For this 15' check size, the group differences were related to significantly increased latency and reduced amplitude of responses in the group with overt hypothyroidism compared with controls. There was no difference between the groups (hypothyroid vs control) with 60 min of arc check size. There was a significant correlation between severity of the disease and PVEP component. CONCLUSIONS In conclusion, low levels of circulating hypothyroid hormone are associated with delay in the pattern VEP to small check sizes. This CNS involvement worsens in patients with greater severity and duration of hypothyroidism.
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Affiliation(s)
- Abbas Azimi
- Department of Optometry, School of Paramedical Sciences, Mashhad University of Medical Sciences, Azadi Square, Pardis Ferdowsi, 91779-48964, Mashhad, Iran.,Refractive Errors Research Center, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Shokoufeh Bonakdaran
- Endocrine Research Center, Ghaem Hospital, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Javad Heravian
- Department of Optometry, School of Paramedical Sciences, Mashhad University of Medical Sciences, Azadi Square, Pardis Ferdowsi, 91779-48964, Mashhad, Iran.,Refractive Errors Research Center, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Parvin Layegh
- Endocrine Research Center, Imam Reza Hospital, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Negareh Yazdani
- Department of Optometry, School of Paramedical Sciences, Mashhad University of Medical Sciences, Azadi Square, Pardis Ferdowsi, 91779-48964, Mashhad, Iran.,Refractive Errors Research Center, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Maryam Alborzi
- Department of Optometry, School of Paramedical Sciences, Mashhad University of Medical Sciences, Azadi Square, Pardis Ferdowsi, 91779-48964, Mashhad, Iran.
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Sawant O, Horton AM, Shukla M, Rayborn ME, Peachey NS, Hollyfield JG, Rao S. Light-Regulated Thyroid Hormone Signaling Is Required for Rod Photoreceptor Development in the Mouse Retina. Invest Ophthalmol Vis Sci 2016; 56:8248-57. [PMID: 26720479 DOI: 10.1167/iovs.15-17743] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
PURPOSE Ambient light is both a stimulus for visual function and a regulator of photoreceptor physiology. However, it is not known if light can regulate any aspect of photoreceptor development. The purpose of this study was to investigate whether ambient light is required for the development of mouse rod photoreceptors. METHODS Newborn mouse pups (C57BL/6) were reared in either cyclic light (LD) or constant dark (DD). Pups were collected at postnatal day (P)5, P10, P17, or P24. We performed retinal morphometric and cell death analysis at P5, P10, and P17. Rhodopsin expression was assessed using immunofluorescence, Western blot, and quantitative RT-PCR analysis. Electroretinograms were performed at P17 and P24. Radioimmunoassay and ELISA were used to follow changes in thyroid hormone levels in the serum and vitreous. RESULTS In the DD pups, the outer nuclear layer was significantly thinner at P10 and there were higher numbers of apoptotic cells at P5 compared to the LD pups. Rhodopsin expression was lower at P10 and P17 in DD pups. Electroretinogram a-waves were reduced in amplitude at P17 in the DD pups. The DD animals had lower levels of circulating thyroid hormones at P10. Light-mediated changes in thyroid hormones occur as early as P5, as we detected lower levels of total triiodothyronine in the vitreous from the DD animals. Drug-induced developmental hypothyroidism resulted in lower rhodopsin expression at P10. CONCLUSIONS Our data demonstrate that light exposure during postnatal development is required for rod photoreceptor development and that this effect could be mediated by thyroid hormone signaling.
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Affiliation(s)
- Onkar Sawant
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States
| | - Amanda M Horton
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States
| | - Meenal Shukla
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States
| | - Mary E Rayborn
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States
| | - Neal S Peachey
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States 2Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio, United States 3Louis Sto
| | - Joe G Hollyfield
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States 2Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio, United States
| | - Sujata Rao
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States 2Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio, United States
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Electromyographic evaluation of blink reflex as a tool for early diagnosis of neurological dysfunction in patients of hypothyroidism. Ann Neurosci 2013; 20:95-8. [PMID: 25206024 PMCID: PMC4117124 DOI: 10.5214/ans.0972.7531.200304] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Revised: 03/05/2013] [Accepted: 05/10/2013] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Neurological dysfunction is an important consequence of hypothyroidism. Some of the neurologic manifestations of hypothyroidism include somnolence, lethargy, impaired memory and concentration, depression and entrapment neuropathy. Rarer but reversible neurological manifestations include cerebellar ataxia, psychosis, dementia and myxedema coma. PURPOSE The aim of the present study was to evaluate the usefulness of the blink reflex as a method for obtaining an early diagnosis of central nervous system dysfunction in hypothyroid patients who do not have signs or symptoms of nervous system dysfunction. METHODS Forty-eight patients with mean age 40 (± 11), with newly diagnosed primary hypothyroidism and 20 healthy control subjects were included in the study. The patients were divided into subclinical and overt hypothyroidism. Patients with normal T3/T4 with elevated TSH were considered subclinical hypothyroids. For blink reflex testing, subjects lay supine on a bed in a warm room with eyes gently closed. Recordings were performed with an EMG machine (Nihon Kohdeni'Neuropack), with a filter setting of 20 Hz to 10 kHz, using an analysis time of 50 ms. Recordings were performed with surface recording electrodes (Dantec 13K60, Copenhagen, Denmark). RESULTS Second ipsilateral response (R2I) and second contralateral response (R2C) latencies in hypothyroidism were prolonged relative to controls, and the differences were statistically significant (P<0.001 and P<0.001, respectively). Latency of Rl, R2I, and R2C did not correlate linearly free T3, free T4, or TSH values in the hypothyroid group. CONCLUSION The finding of abnormal blink reflex responses in hypothyroid individuals raises the notion that they may be useful in detecting early changes and in the follow-up of the patients with the disorder.
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Nazliel B, Akbay E, Irkeç C, Yetkin I, Ersoy R, Törüner F. Pattern visual evoked potential (PVEP) evaluation in hypothyroidism. J Endocrinol Invest 2002; 25:955-8. [PMID: 12553554 DOI: 10.1007/bf03344067] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Dysfunction of the central nervous system (CNS) is an important consequence of thyroid hormone deficiency. Evoked potentials like visual evoked potentials (VEP) provide a reliable and objective measure of function in related sensory system and tracts. In this study pattern-shift VEP (PVEP) recordings were performed on 48 newly diagnosed hypothyroid patients. Twenty-four had sub-clinical and 24 had overt hypothyroidism. None of the patients had clinical symptoms or signs referable to CNS dysfunction. Their mean age was 44+/-12 yr. The response to pattern stimulation on the normal control subjects was a triphasic response with a prominent positive wave (P100) with a peak latency of 84-105 (mean: 96+/-4) milliseconds (ms). In patients with hypothyroidism mean P100 latency was (mean: 97+/-6) ms and the difference between the 2 groups was not statistically significant. (p>0.05) Delays above the average latency +/-2.5 SD of the mean of the control subjects was defined as a criteria for an abnormality. According to defined criteria 6 (12.5%) patients demonstrated abnormal PVEP at least on one tested side. Previous studies conducted on small patient populations stated there is high percentage of VEP abnormalities in hypothyroid patients. However, this fact was not confirmed by our study. We believe abnormalities of PVEP will be more prominent in untreated patients in the advanced stage of the disease, or in patients who have a neurological involvement; such as apathy, impaired memory or cerebellar dysfunction. Consecutive studies, in a more clearly defined and selected patient population, are needed to confirm and settle this issue.
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Affiliation(s)
- B Nazliel
- Faculty of Medicine, Gazi University, Ankara, Turkey.
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Dolu N, Süer C, Ozesmi C, Keleştimur F, Ozcan Y. Electrodermal activity in hypothyroid patients and healthy subjects. Thyroid 1999; 9:787-90. [PMID: 10482371 DOI: 10.1089/thy.1999.9.787] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The involvement of the central nervous system either in hypothyroidism or in hyperthyroidim has previously been shown on the basis of visual, auditory, somatosensory, and central motor evoked potential studies by some investigators. In to our previous study, we found that abnormal electrodermal activity in nonmedicated hyperthyroid patients was not associated with psychiatric symptoms. In this study, our purpose was to investigate whether hypothyroidism results in electrodermal abnormalities in the absence of measurable psychiatric symptoms. Electrodermal activity was recorded with a skin conductance unit connected to a personal computer. Basal levels of electrodermal activity and responsiveness to repeated acoustic stimulation were studied in 14 nonmedicated hypothyroid patients and 14 healthy controls. Psychiatric rating scores indicated that patients and healthy controls had normal levels of anxiety and depression. Hypothyroid patients had lower skin conductance levels, lower fluctation rates and prolonged onset latencies compared with controls. None of the hypothyroid patients had amplitude changes. In conclusion, hypothyroid patients may have abnormal electrodermal activity that is related to the change of hypothalamic-pituitary-thyroid axis function, without associated psychiatric symptoms.
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Affiliation(s)
- N Dolu
- Department of Physiology, Faculty of Medicine, Erciyes University, Kayseri, Turkey.
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Ozata M, Ozkardes A, Corakci A, Beyhan Z, Gundogan MA. Event-Related Brain Potentials in Patients with Hypothyroidism. Endocr Pract 1997; 3:349-52. [PMID: 15251772 DOI: 10.4158/ep.3.6.349] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
OBJECTIVE To evaluate the cognitive function of patients with hypothyroidism, based on long-latency auditory event-related potentials (ERPs). METHODS We investigated alterations of P300 latency in patients with hypothyroidism before treatment and after restoration of euthyroidism. ERPs were elicited in 14 untreated patients with hypothyroidism (mean age, 26.71 +/- 2.39 years) and in a group of 30 control subjects with comparable mean age, sex distribution, and educational level. ERP recordings were repeated at 1 and 6 months after attainment of euthyroidism. RESULTS Untreated patients with hypothyroidism had longer P300 and N1 wave latencies in comparison with those in the control subjects (P = 0.003 and P = 0.018, respectively). The mean P300 latencies did not change significantly 1 month after restoration of euthyroidism. At 6 months after attainment of euthyroidism, however, the mean P300 latencies returned to normal values, similar to those in the control subjects. CONCLUSION We conclude that P300 latencies are impaired in patients with hypothyroidism, which is indicative of cognitive dysfunction. These alterations, however, may be reversed 6 months after attainment of euthyroidism.
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Affiliation(s)
- M Ozata
- Department of Endocrinology and Metabolism, Gulhane School of Medicine, Etlik-Ankara 06018, Turkey
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Spadea L, Bianco G, Dragani T, Balestrazzi E. Early detection of P-VEP and PERG changes in ophthalmic Graves' disease. Graefes Arch Clin Exp Ophthalmol 1997; 235:501-5. [PMID: 9285219 DOI: 10.1007/bf00947007] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND In Graves' disease the optic neuropathy (ON) is due to direct compression of the nerve and/or of its blood supply. The aim of the present study was to detect early changes in the visual functions of patients affected by ophthalmic Graves' disease (OGD) by using electrophysiological tests (P-VEP and PERG). METHODS We studied 50 OGD patients who were in a range between class 2 and class 5 according to the Donaldson-American Thyroid Association classification, i.e. had no evident ON and normal visual acuity. We recorded transient reversal PERG and P-VEP in response to the stimulation of one eye at three spatial frequencies (2.2, 1.1 and 0.5 c/d). RESULTS Our results showed a statistically significant reduction in PERG amplitude in class 5, while the P-VEP amplitude was already reduced in class 2. CONCLUSION The electrofunctional tests were useful to detect small changes in the visual function of patients affected by initial stages of OGD. Therefore, P-VEP and PERG recordings appear to be a useful tool for early diagnosis of the optic nerve involvement in Graves' disease.
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Affiliation(s)
- L Spadea
- University of L'Aquila, Department of Ophthalmology, Italy
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Ozata M, Ozkardes A, Dolu H, Corakçi A, Yardim M, Gundogan MA. Evaluation of central motor conduction in hypothyroid and hyperthyroid patients. J Endocrinol Invest 1996; 19:670-7. [PMID: 9007698 DOI: 10.1007/bf03349037] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Deficiency or excess of thyroid hormones is associated with central nervous system (CNS) disturbances. Although the CNS involvement either in hypothyroidism or in hyperthyroidism have previously been shown on the basis of visual, auditory and somatosensory evoked potentials studies, less is known about the function of central motor pathways in both disorders. We studied the motor evoked potentials (MEPs) following the magnetic stimulation of the motor cortex and spinal roots in 20 patients with hypothyroidism and in 19 patients with hyperthyroidism both before treatment and after they became euthyroid and compared with findings in 20 age-, sex- and height-matched control subjects. Disease duration (expressed as time from diagnosis of diseases to the time of neurological testing) is less than one month in both disorders. Central motor conduction time (CMCT) was determined as the differences between MEPs latencies after cortical and spinal stimulation. The mean CMCTs before treatment in hypothyroid patients (8.31 +/- 1.52 msec.) and in hyperthyroid patients (7.92 +/- 1.06 msec.) were significantly prolonged as compared to those in normal controls (6.82 +/- 0.83 msec. p = 0.002 and p = 0.004, respectively). Four of the 20 (20.0%) hypothyroid patients and 2 of 19 (10.5%) hyperthyroid patients had abnormal CMCT (values exceeding mean +2.5 SD of normal control). The mean CMCT values in both groups were not significantly decreased after euthyroidism was achieved, although a tendency of the decrease in CMCT was observed. Improvement of CMCT abnormalities was observed in 1 of 4 hypothyroid patients and in one of 2 patients with hyperthyroidism, who had CMCT abnormalities before treatments, after they became euthyroid. No correlation was found between CMCT and free T3, free T4, or TSH levels as well as the onset age, the severity of the diseases or the disease duration in both disorders. We conclude that abnormal CMCT could be documented in few patients in both disorders. However, these alterations could not be improved completely after restoration of euthyrodism. Thus, it remains to be determined if long-term treatment would completely improve CMCT abnormalities in both disorders. Since abnormal CMCT values in both disorders were observed only in few patients, our results also suggest that CMCT measurement does not have, at present time, a clinical usefulness to assess the peripheral action of thyroid hormones. Thus, the data obtained need a more extensive evaluation.
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Affiliation(s)
- M Ozata
- Department of Endocrinology and Metabolism, Gulhane School of Medicine, Etlik-Ankara, Turkey
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Ozkardes A, Ozata M, Beyhan Z, Corakci A, Vural O, Yardim M, Gundogan MA. Acute hypothyroidism leads to reversible alterations in central nervous system as revealed by somatosensory evoked potentials. ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY 1996; 100:500-4. [PMID: 8980414 DOI: 10.1016/s0168-5597(96)96520-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Although functional alterations in the central nervous system (CNS) and peripheral nerves are well documented in overt hypothyroidism, little is known about alterations of CNS in acute hypothyroidism. Sixteen patients with differentiated thyroid carcinoma were studied when prepared for radioiodine scanning after stopping levothyroxine (L-T4) therapy for 6 weeks to determine whether acute hypothyroidism leads to alteration in somatosensory evoked potentials (SSEPs). Repeat SSEPs were performed on the same patients at 6 months following L-T4 therapy when patients were euthyroid. Neurophysiological findings were compared with a group of 20 normal controls with no history of thyroid disease. Peripheral and central conduction in the median and tibial nerve stimulated SSEPs studied. A significant prolongation of central conduction time in SSEPs was found in patients with acute hypothyroidism when compared to those in control subjects. Abnormal latencies were not correlated with thyroid hormone levels. These neurophysiologic abnormalities were completely restored to normal at 6 months after L-T4 therapy. We conclude that acute hypothyroidism leads to reversible alterations in CNS as determined by SSEP recordings. Our results also suggest that SSEPs could be useful tests to monitor functional alteration of the CNS in acute hypothyroidism.
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Affiliation(s)
- A Ozkardes
- Department of Neurology, Gulhane School of Medicine, Etlik-Ankara, Turkey
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Bauer MS, Soloway A, Dratman MB, Kreider M. Effects of hypothyroidism on rat circadian activity and temperature rhythms and their response to light. Biol Psychiatry 1992; 32:411-25. [PMID: 1486147 DOI: 10.1016/0006-3223(92)90129-n] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Male rats made hypothyroid by administration of propylthiouracil plus sodium ipodate in drinking water were compared to controls in terms of period of circadian activity and temperature rhythms, amount of gross motor activity, and mean temperature. Animals were studied under entrainment, constant darkness (DD), and constant dim light (LL). There was no difference in the period of the circadian activity rhythm between groups in DD. However, hypothyroid rats showed significant blunting of the period-lengthening response to increasing ambient illumination. As expected, the period of the circadian temperature rhythm increased in controls with increasing ambient illumination. In contrast, the period of the circadian temperature rhythm in hypothyroid animals actually shortened under LL compared to DD. This blunting of the period-lengthening response to increasing ambient illumination of both activity and temperature rhythms in hypothyroid animals could not be explained by differences in activity level or mean temperature between the groups.
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Affiliation(s)
- M S Bauer
- Department of Veterans Affairs Medical Center, Providence, RI 02908-4799
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Holder GE, Condon JR. Pattern visual evoked potentials and pattern electroretinograms in hypothyroidism. Doc Ophthalmol 1989; 73:127-31. [PMID: 2638622 DOI: 10.1007/bf00155030] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
This study reports the pattern visual evoked potential (PVEP) findings in 10 patients with idiopathic hypothyroidism. Eight of these patients also had pattern electroretinography (PERG) performed and six were additionally seen after treatment with thyroxine. Only one patient had definitely abnormal PVEPs at the time of initial recording. PERGs at this time were of abnormal latency and subnormal amplitude. Following treatment with thyroxine the patient became euthyroid. Repeat electrodiagnostic testing now showed both PERGs and PVEPs within the normal range, having markedly improved in both latency and amplitude. This suggests that the PVEP delay was probably secondary to reversible central retinal dysfunction.
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Affiliation(s)
- G E Holder
- Department of Clinical Neurophysiology, Brook General Hospital, London, UK
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Abstract
Pattern reversal visual evoked potentials (VEPs) have been elicited in 16 female hyperthyroid patients before and after treatment and compared with those from a similar group of age and sex matched control subjects. No effect on latency was seen, and although larger amplitude values were noted in the thyrotoxic group these too were not significant. We would conclude that hyperthyroidism per se has little effect on the pattern reversal VEP, and any observed effect on these potentials is probably due to other factors.
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Affiliation(s)
- K W Mitchell
- University Department of Ophthalmology, Royal Victoria Infirmary, Newcastle upon Tyne
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Laureau E, Hebert R, Vanasse M, Letarte J, Glorieux J, Desjardins M, Dussault JH. Somatosensory evoked potentials and auditory brain-stem responses in congenital hypothyroidism. II. A cross-sectional study in childhood. Correlations with hormonal levels and developmental quotients. ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY 1987; 67:521-30. [PMID: 2445544 DOI: 10.1016/0013-4694(87)90054-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
We report the results of somatosensory evoked potentials (SEPs) and auditory brain-stem responses (ABRs) done in 48 congenital hypothyroid (CH) treated children, early detected and aged 18 months, 3 and 5-9 years of age. We report also the results of SEP and ABR done in 9 3-year-old CH children, before and after a 1 month therapy interruption to reassess the thyroid status. The more frequent abnormalities were increased wave I latencies for 18 month and 3-year-old CH children. In some children, these increases were not associated with signs of otitis media. No significant difference was seen between CH children and controls for SEP latencies and ABR and SEP interpeak latencies (IPLs). Similarly, no significant difference was seen between the two recording sessions in the 9 3-year-old CH children for ABR and SEP. On an individual basis, we observed abnormalities of central conduction time for ABR and SEP in several CH children. Moreover, significant partial correlations were found between ABR and SEP IPLs and thyroxine (T4) serum levels at diagnosis and thyrotropin (TSH) serum levels at the time of recording. There was also a significant partial correlation between N19-P22 IPLs and the practical reasoning scale of the Griffiths test considering the whole group of CH children. These results indicate that SEP might eventually be used to detect CH children at risk of presenting developmental abnormalities.
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Affiliation(s)
- E Laureau
- Laboratoire d'Electrophysiologie Médicale, Hôpital Sint-Justine, Université de Montréal, Que., Canada
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Laureau E, Vanasse M, Hebert R, Letarte J, Glorieux J, Desjardins M, Dussault JH. Somatosensory evoked potentials and auditory brain-stem responses in congenital hypothyroidism. I. A longitudinal study before and after treatment in six infants detected in the neonatal period. ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY 1986; 64:501-10. [PMID: 2430772 DOI: 10.1016/0013-4694(86)90186-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
We report the results of a longitudinal study of auditory brain-stem responses (ABRs) and somatosensory evoked potentials (SEPs) performed in 6 children with congenital hypothyroidism. These infants were detected by the Quebec Network for Genetic Medicine and treated early. ABRs and SEPs were recorded both before and 2 weeks after the initiation of therapy and at 6 months of age. Before treatment, for SEP, we found increased wave N19, P22 latencies and N13-N19, N19-P22 interpeak latencies (IPLs) in congenital hypothyroid (CH) children. For ABR, there were increased wave I latencies with normal I-V IPLs. Substitutive therapy improved these abnormalities although this improvement was more evident after a shorter period of time for ABRs than for SEPs. Even at 6 months, 2 CH children still showed increased N13-N19 IPLs. Both had very low serum T4 levels at the time of diagnosis and one had also a very small knee surface area, both criteria indicating a severe hypothyroidism. It will be interesting to verify if initial and persisting increase of N13-N19 IPL is associated with later neuropsychological problems.
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O'Malley BP, Abbott RJ, Timson L, Beck AD, Rosenthal FD. Sensory thresholds and motor responsiveness in thyroid disease: their responses to treatment and warming. Clin Endocrinol (Oxf) 1985; 23:17-23. [PMID: 4028463 DOI: 10.1111/j.1365-2265.1985.tb00178.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
It has been our clinical observation that patients with hypothyroidism are relatively insensitive to the discomfort of venepuncture, whereas thyrotoxic patients seem to have a heightened sensitivity. In an initial study we have measured the sensory thresholds of perception along with motor responsiveness in hypothyroid, thyrotoxic and euthyroid subjects, employing a simple and readily reproducible technique. Sensory thresholds were elevated and motor responsiveness impaired in hypothyroid subjects as compared to euthyroid controls. In thyrotoxic subjects, motor responsiveness was significantly enhanced, but sensory thresholds did not differ from control values. In a subsequent study the threshold abnormalities of thyroid dysfunction were corrected by rendering the patients euthyroid with appropriate therapy. Warming a further group of untreated hypothyroid patients produced a similar improvement in motor responsiveness to that seen in the L-thyroxine-treated group, thus implying that this parameter is at least, in part, temperature dependent. Sensory thresholds would seem to be reliable reflectors of tissue thyroid status in hypothyroidism, whereas motor responsiveness seems the better guide to thyroid status across the whole spectrum of thyroid function.
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O'Malley BP, Abbott RJ, Barnett DB, Northover BJ, Rosenthal FD. Propranolol versus carbimazole as the sole treatment for thyrotoxicosis. A consideration of circulating thyroid hormone levels and tissue thyroid function. Clin Endocrinol (Oxf) 1982; 16:545-52. [PMID: 7105427 DOI: 10.1111/j.1365-2265.1982.tb03171.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Ruiz-Marcos A, Sánchez-Toscano F, Escobar del Rey F, Morreale de Escobar G. Reversible morphological alterations of cortical neurons in juvenile and adult hypothyroidism in the rat. Brain Res 1980; 185:91-102. [PMID: 7353183 DOI: 10.1016/0006-8993(80)90674-5] [Citation(s) in RCA: 65] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
We have studied: (i) whether or not hypothyroidism induced experimentally in the adult rat affects the number and distribution of spines along the apical shaft of pyramidal cells from the visual cortex; and (ii) whether treatment with thyroid hormone would reverse such changes. Two experiments were performed. Experiment A involved the study of rats which were thyroidectomized (T) at 40 or at 120 days of age, killed at 120 and 220 days of age, respectively, data being compared to those of adequate sex and age-paired controls. Experiment B involved rats which were T at 40 days of age; they were subdivided into two groups, one of which was left untreated and the other received 0.2 microgram of thyroxine/100 g body weight/day for 25 days. Both groups were killed at 90 days of age. We found that: (i) T at 40 and at 120 days of age resulted in a decrease of the number of spines and a derangement of their distribution along the shaft, the observed changes being qualitatively comparable to those previously described for rats T at 10 days of age; and (ii) preliminary results from experiment B indicate that the observed changes in neuronal morphology might be reversible. It is suggested that age-independent and reversible alterations of learning capacity and electrocortical activity of hypothyroid rats might have age-independent and reversible morphological correlates at the level of the cortex.
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