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McGregor O, Genain MA, Williams TL, Alves L. Prevalence and clinical correlations of olfactory recess dilatation in MRI studies of the feline brain. Vet Radiol Ultrasound 2023. [PMID: 36798054 DOI: 10.1111/vru.13218] [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: 09/08/2022] [Revised: 01/08/2023] [Accepted: 01/10/2023] [Indexed: 02/18/2023] Open
Abstract
The ability to differentiate clinical ventriculomegaly from incidental ventricular enlargement remains a challenge in veterinary radiology. Dilatation of one or both olfactory lobe recesses is occasionally seen on MRI of the brain in otherwise normal cats. The purpose of this study was therefore to determine the prevalence of this finding within a population of neurologically normal and neurologically abnormal cats, and to investigate associations with signalment, clinical and neurological examination findings, and MRI features. An observational retrospective cohort study was performed, and archived records were searched for cats that had undergone MRI of the head, including the olfactory lobes. Medical data and MRI parameters were recorded. One hundred fifty-one cats were included, with olfactory recess dilatation present in 56 cats. In 16 neurologically normal cats, olfactory recess dilatation was the only MRI finding. Olfactory recess dilatation was not associated with age, sex, breed, or with the presence of nasal disease. A significant association was found between generalized ventriculomegaly (P = 0.001) and the presence of CSF abnormalities (P = 0.036). Eleven percent of our cohort (16/151) demonstrated olfactory recess dilatation in the absence of other neurological or structural intracranial disease, suggesting that this may be seen as a normal variation in some cats.
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Affiliation(s)
- Ombeline McGregor
- Department of Veterinary Medicine, Queen's Veterinary School Hospital, Cambridge, UK
| | - Marie-Aude Genain
- Department of Veterinary Medicine, Queen's Veterinary School Hospital, Cambridge, UK
| | - Timothy Lee Williams
- Department of Veterinary Medicine, Queen's Veterinary School Hospital, Cambridge, UK
| | - Lisa Alves
- Department of Veterinary Medicine, Queen's Veterinary School Hospital, Cambridge, UK
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2
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Hu B, Zhang J, Gong M, Deng Y, Cao Y, Xiang Y, Ye D. Research Progress of Olfactory Nerve Regeneration Mechanism and Olfactory Training. Ther Clin Risk Manag 2022; 18:185-195. [PMID: 35281777 PMCID: PMC8906848 DOI: 10.2147/tcrm.s354695] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Accepted: 02/28/2022] [Indexed: 11/24/2022] Open
Abstract
The olfactory nerve (ON) is the only cranial nerve exposed to the external environment. Hence, it is susceptible to damage from head trauma, viral infection, inflammatory stimulation, and chemical toxins, which can lead to olfactory dysfunction. However, compared with all other cranial nerves, the ON is unique due to its inherent ability to regenerate. This characteristic provides a theoretical basis for treatment of olfactory dysfunction. Olfactory training (OT) is one of the main treatments for olfactory dysfunction. It is easy to apply and has few side-effects, and has been shown to be efficacious for patients with olfactory dysfunction of various causes. To further understand the application value of ON regeneration and OT on olfactory dysfunction, we review the research progress on the mechanism of ON regeneration and OT.
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Affiliation(s)
- Bian Hu
- Department of Otorhinolaryngology-Head and Neck Surgery, Lihuili Hospital of Ningbo University, Ningbo, 315040, Zhejiang, People’s Republic of China
- Department of Otorhinolaryngology-Head and Neck Surgery, Ninghai First Hospital, Ningbo, 315699, Zhejiang, People’s Republic of China
| | - Jingyu Zhang
- Shanghai Jiao Tong University, Shanghai, 200030, People’s Republic of China
| | - Mengdan Gong
- Department of Otorhinolaryngology-Head and Neck Surgery, Lihuili Hospital of Ningbo University, Ningbo, 315040, Zhejiang, People’s Republic of China
| | - Yongqin Deng
- Department of Otorhinolaryngology-Head and Neck Surgery, Lihuili Hospital of Ningbo University, Ningbo, 315040, Zhejiang, People’s Republic of China
| | - Yujie Cao
- Department of Otorhinolaryngology-Head and Neck Surgery, Lihuili Hospital of Ningbo University, Ningbo, 315040, Zhejiang, People’s Republic of China
| | - Yizhen Xiang
- Department of Otorhinolaryngology-Head and Neck Surgery, Lihuili Hospital of Ningbo University, Ningbo, 315040, Zhejiang, People’s Republic of China
| | - Dong Ye
- Department of Otorhinolaryngology-Head and Neck Surgery, Lihuili Hospital of Ningbo University, Ningbo, 315040, Zhejiang, People’s Republic of China
- Correspondence: Dong Ye, Department of Otorhinolaryngology-Head and Neck Surgery, Lihuili Hospital of Ningbo University, Ningbo, 315040, Zhejiang, People’s Republic of China, Tel +86 13819861213, Fax +86 574-87392232, Email
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3
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Petitpierre G, Dind J, De Blasio C, Gremaud G. Odour detection in children and young people with profound intellectual and multiple disabilities. JOURNAL OF APPLIED RESEARCH IN INTELLECTUAL DISABILITIES 2021; 35:519-530. [PMID: 34859541 PMCID: PMC9299868 DOI: 10.1111/jar.12963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 11/10/2021] [Accepted: 11/14/2021] [Indexed: 11/26/2022]
Abstract
BACKGROUND Olfaction provides information on very important dimensions of the environment; however the olfactory abilities of children and young people with profound intellectual and multiple disabilities (PIMD) remain largely unknown. This within-subjects study explores olfactory detection abilities in children with PIMD. METHOD Twenty-two children and young people with PIMD (7-18 years) were presented with 18 medium intensity odours and an odourless control stimulus. Odorants were presented one by one in a randomised order. The neutral stimulus was presented prior to each odorant. Participants' responses were measured using 21 behavioural indicators. RESULTS Results show that participants make a clear distinction between odorous and neutral conditions, between food and non-food, and between pleasant and unpleasant odours. The detection abilities are manifested by several behaviours, in particular by the duration of the head alignment on the odorant. CONCLUSIONS This study shows that participants detect the stimuli and act differently depending on the category.
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Affiliation(s)
| | - Juliane Dind
- Department of Special Education, University of Fribourg, Fribourg, Switzerland
| | - Catherine De Blasio
- Department of Special Education, University of Fribourg, Fribourg, Switzerland
| | - Germaine Gremaud
- Department of Special Education, University of Fribourg, Fribourg, Switzerland
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Transitory and Vestigial Structures of the Developing Human Nervous System. Pediatr Neurol 2021; 123:86-101. [PMID: 34416613 DOI: 10.1016/j.pediatrneurol.2021.07.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Revised: 07/02/2021] [Accepted: 07/03/2021] [Indexed: 11/23/2022]
Abstract
As with many body organs, the human central nervous system contains many structures and cavities that may have had functions in embryonic and fetal life but are vestigial or atrophic at maturity. Examples are the septum pellucidum, remnants of the lamina terminalis, Cajal-Retzius neurons, induseum griseum, habenula, and accessory olfactory bulb. Other structures are transitory in fetal or early postnatal life, disappearing from the mature brain. Examples are the neural crest, subpial granular glial layer of Brun over cerebral cortex, radial glial cells, and subplate zone of cerebral cortex. At times persistent fetal structures that do not regress may cause neurological problems or indicate a pathologic condition, such as Blake pouch cyst. Transitory structures thus can become vestigial. Examples are an excessively wide cavum septi pellucidi, suprapineal recess of the third ventricle, trigeminal artery of the posterior fossa circulation, and hyaloid ocular artery. Arrested maturation might be considered another aspect of vestigial structure. An example is the persistent microcolumnar cortical architecture in focal cortical dysplasia type Ia, in cortical zones of chronic fetal ischemia, and in some metabolic/genetic congenital encephalopathies. Some transitory structures in human brain are normal adult structures in lower vertebrates. Recognition of transitory and vestigial structures by fetal or postnatal neuroimaging and neuropathologically enables better understanding of cerebral ontogenesis and avoids misinterpretations.
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Lyons-Warren AM, Herman I, Hunt PJ, Arenkiel BR. A systematic-review of olfactory deficits in neurodevelopmental disorders: From mouse to human. Neurosci Biobehav Rev 2021; 125:110-121. [PMID: 33610612 PMCID: PMC8142839 DOI: 10.1016/j.neubiorev.2021.02.024] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 01/15/2021] [Accepted: 02/15/2021] [Indexed: 01/07/2023]
Abstract
Olfactory impairment is a common clinical motif across neurodevelopmental disorders, suggesting olfactory circuits are particularly vulnerable to disease processes and can provide insight into underlying disease mechanisms. The mouse olfactory bulb is an ideal model system to study mechanisms of neurodevelopmental disease due to its anatomical accessibility, behavioral relevance, ease of measuring circuit input and output, and the feature of adult neurogenesis. Despite the clinical relevance and experimental benefits, olfactory testing across animal models of neurodevelopmental disease has been inconsistent and non-standardized. Here we performed a systematic literature review of olfactory function testing in mouse models of neurodevelopmental disorders, and identified intriguing inconsistencies that include evidence for both increased and decreased acuity in odor detection in various mouse models of Autism Spectrum Disorder (ASD). Based on our identified gaps in the literature, we recommend direct comparison of different mouse models of ASD using standardized tests for odor detection and discrimination. This review provides a framework to guide future olfactory function testing in mouse models of neurodevelopmental diseases.
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Affiliation(s)
- Ariel M Lyons-Warren
- Baylor College of Medicine, Department of Pediatrics, Section of Pediatric Neurology and Developmental Neuroscience; Clinical Care Center, Suite 1250, 6621 Fannin St, Houston, TX 77030, United States of America;,Jan and Dan Duncan Neurological Research Institute at Texas Children’s Hospital, Houston, TX 77030 USA
| | - Isabella Herman
- Baylor College of Medicine, Department of Pediatrics, Section of Pediatric Neurology and Developmental Neuroscience; Clinical Care Center, Suite 1250, 6621 Fannin St, Houston, TX 77030, United States of America;,Baylor College of Medicine, Department of Molecular & Human Genetics; 1250 Moursund Street, Suite 1170.12, Houston TX 77030, United States of America
| | - Patrick J Hunt
- Baylor College of Medicine, Department of Molecular & Human Genetics; 1250 Moursund Street, Suite 1170.12, Houston TX 77030, United States of America
| | - Benjamin R Arenkiel
- Baylor College of Medicine, Department of Molecular & Human Genetics; 1250 Moursund Street, Suite 1170.12, Houston TX 77030, United States of America;,Baylor College of Medicine, Department of Neuroscience; 1250 Moursund Street, Suite 1170.12, Houston TX 77030, United States of America;,Jan and Dan Duncan Neurological Research Institute at Texas Children’s Hospital, Houston, TX 77030 USA.,McNair Medical Institute, Baylor College of Medicine, Houston, TX 77030
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6
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Olfactory Perception in Relation to the Physicochemical Odor Space. Brain Sci 2021; 11:brainsci11050563. [PMID: 33925220 PMCID: PMC8146962 DOI: 10.3390/brainsci11050563] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 04/23/2021] [Accepted: 04/26/2021] [Indexed: 11/29/2022] Open
Abstract
A growing body of research aims at solving what is often referred to as the stimulus-percept problem in olfactory perception. Although computational efforts have made it possible to predict perceptual impressions from the physicochemical space of odors, studies with large psychophysical datasets from non-experts remain scarce. Following previous approaches, we developed a physicochemical odor space using 4094 molecular descriptors of 1389 odor molecules. For 20 of these odors, we examined associations with perceived pleasantness, intensity, odor quality and detection threshold, obtained from a dataset of 2000 naïve participants. Our results show significant differences in perceptual ratings, and we were able to replicate previous findings on the association between perceptual ratings and the first dimensions of the physicochemical odor space. However, the present analyses also revealed striking interindividual variations in perceived pleasantness and intensity. Additionally, interactions between pleasantness, intensity, and olfactory and trigeminal qualitative dimensions were found. To conclude, our results support previous findings on the relation between structure and perception on the group level in our sample of non-expert raters. In the challenging task to relate olfactory stimulus and percept, the physicochemical odor space can serve as a reliable and helpful tool to structure the high-dimensional space of olfactory stimuli. Nevertheless, human olfactory perception in the individual is not an analytic process of molecule detection alone, but is part of a holistic integration of multisensory inputs, context and experience.
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Costa I, Rodrigues B, Dias L. Congenital Agenesis of the Olfactory Bulbs: What to Suspect? Cureus 2021; 13:e12659. [PMID: 33585143 PMCID: PMC7872876 DOI: 10.7759/cureus.12659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Complete agenesis of the olfactory bulbs (OB) constitutes a rare cause of congenital anosmia, which is more often associated with cerebral malformations or genetic disorders. The authors present a very rare case of a 28-year-old caucasian male with complaints of complete lack of the sense of smell since childhood. Radiologic study confirmed complete bilateral agenesis of the OB, with no other radiologic or clinical findings, such as delayed sexual development. Laboratorial investigation confirmed no signs of adrenocortical insufficiency. Despite being immature in the term neonate, the OB are already functional at birth. Congenital agenesis of the OB can occur as an isolated deformity. On the other hand, it is a constant feature of several genetic syndromes, such as Kallmann's syndrome or alobar holoprosencephaly. Most cases of isolated congenital anosmia occur sporadically, with no family history of the condition. Given the fact that no curative treatment is available, counselling for daily living precautions should be given to all patients. This is one of the first case reports about complete and isolated agenesia of the OB diagnosed in adulthood. The authors highlight the need to exclude several genetic syndromes that may be associated, albeit in a dissimulated way.
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Affiliation(s)
- Isabel Costa
- Otorhinolaryngology and Head and Neck Surgery Department, Hospital de Braga, Braga, PRT
| | - Berta Rodrigues
- Otorhinolaryngology and Head and Neck Surgery Department, Hospital de Braga, Braga, PRT
| | - Luís Dias
- Otorhinolaryngology and Head and Neck Surgery Department, Hospital de Braga, Braga, PRT
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Karaoglan M, Colakoglu Er H. Radiological evidence to changes in the olfactory bulb volume depending on body mass index in the childhood. Int J Pediatr Otorhinolaryngol 2020; 139:110415. [PMID: 33035806 DOI: 10.1016/j.ijporl.2020.110415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 09/06/2020] [Accepted: 09/27/2020] [Indexed: 11/19/2022]
Abstract
OBJECTIVE Energy balance is preserved through the exchange between body weight and adipose tissue across the multi-faceted complex network that is composed of the sensorial, metabolic, and neuro-endocrine circuits. The olfactory control of energy homeostasis is maintained through the interplay between the olfactory bulb (OB) and adipose tissue. While extremely studied, most researches still report controversial results and sensorial regulation of obesity is not fully understood. This study aims to investigate the interplay between olfactory bulb volume (OBV) as a radiological clue of sensorial control and obesity in children. SUBJECTS AND METHOD Children (n = 195) were classified into four groups based on body mass index (BMI) percentiles: normal weight (n = 89), overweight (n = 31), obese (n = 32) and morbidly obese (n = 43). OBV were calculated using MRI. RESULTS Mean OBV was higher in children with obesity than in those of normal weights. The means of OBV are found higher in the overweight and obese children (43.76 ± 9.50-49.29 ± 8.61 mm3) than in those of morbidly obese (38.23 ± 11.52 mm3) (p < 0.001). In overweight and obese children, a positive correlation were found between the BMI and OBV (roverweigh = 0.275-robese = 0.377), while in the morbidly obese group, there was a negative correlation (rseverelyobese = -0.445). CONCLUSION This study reveals that OBV is higher in obese children. Also, it shows that there is a positive correlation between OBV and BMI in overweight and obese children and a negative correlation in the morbidly obese group. These radiological bimodal changes in OBV indicate that olfactory control acts to provide energy balance, mediated by positive in the overweight and obese children, negative feedback in the morbidly obese group.
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Affiliation(s)
- Murat Karaoglan
- Division of Pediatric Endocrinology, Gaziantep University Faculty of Medicine, 27070, Gaziantep, Turkey.
| | - Hale Colakoglu Er
- Department of Radiology, Gaziantep University Faculty of Medicine, 27070, Gaziantep, Turkey.
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9
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Sarnat HB, Flores-Sarnat L. Survey on Olfactory Testing by Pediatric Neurologists: Is the Olfactory a "True" Cranial Nerve? J Child Neurol 2020; 35:317-321. [PMID: 31910727 DOI: 10.1177/0883073819896513] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND The olfactory nerve was conceptualized in the 4th century BC by Alcmaeon and described anatomically by Winslow in 1733. Cranial nerves (CNs) were named and numbered by Soemmerring in 1791. Notions still prevail that the olfactory (CN1) is not a "true" cranial nerve. METHODS To confirm our impression that the olfactory nerve is infrequently tested by North American pediatric neurologists, a survey was distributed to members of national pediatric neurology societies in Mexico, Canada, and the United States. A total of 233 responses were received to 6 multiple-choice questions regarding practice patterns examining CN1 in neonates and children and in metabolic, endocrine, and genetic disorders and cerebral malformations. Two of the questions addressed familiarity with neonatal olfactory reflexes and asked whether the olfactory is a "true" cranial nerve. RESULTS Only 16% to 24% of North American pediatric neurologists examine CN1 in neonates, even in conditions in which olfaction may be impaired. About 40% of respondents were aware of olfactory reflexes. A minority 15% did not consider CN1 as a "true" cranial nerve. CONCLUSIONS Olfactory evaluation in neonates is simple, rapid, and inexpensive. It tests parts of the brain not otherwise examined. It may assist diagnosis in cerebral malformations; metabolic, endocrine, and hypoxic encephalopathies; and some genetic diseases, including chromosomopathies. CN1 is neuroanatomically unique and fulfills criteria of a true sensory cranial nerve. We recommend that olfaction be routinely or selectively included during neurologic examination of neonates and children.
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Affiliation(s)
- Harvey B Sarnat
- Departments of Paediatrics, Clinical Neurosciences, Pathology and Laboratory Medicine (Neuropathology), University of Calgary Cumming School of Medicine and Alberta Children's Hospital Research Institute, Calgary, Alberta, Canada
| | - Laura Flores-Sarnat
- Departments of Paediatrics, Clinical Neurosciences, University of Calgary Cumming School of Medicine and Alberta Children's Hospital Research Institute (Owerko Centre), Calgary, Alberta, Canada
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Espinosa‐Jovel C, Toledano R, Jiménez‐Huete A, Aledo‐Serrano Á, García‐Morales I, Campo P, Gil‐Nagel A. Olfactory function in focal epilepsies: Understanding mesial temporal lobe epilepsy beyond the hippocampus. Epilepsia Open 2019; 4:487-492. [PMID: 31440730 PMCID: PMC6698687 DOI: 10.1002/epi4.12343] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Revised: 05/12/2019] [Accepted: 05/28/2019] [Indexed: 11/06/2022] Open
Abstract
Several lines of research have linked olfactory regions with the pathophysiology of focal epilepsies. Among those regions, the piriform cortex represents the major part of the primary olfactory cortex. According to these data, we raised the hypothesis that in patients with mesial temporal lobe epilepsy associated with hippocampal sclerosis exists an interictal dysfunction of olfactory processing that could be more significant compared to patients with extra-hippocampal focal epilepsy and healthy controls. This could be the consequence of a dysfunctional epileptogenic network that extends beyond the hippocampus and affects other structures, including the piriform cortex. To test this hypothesis, we evaluated the olfactory function with the Sniffin' Sticks test in 32 patients with mesial temporal lobe epilepsy associated with hippocampal sclerosis, 30 patients with extra-hippocampal focal epilepsy, and 22 healthy controls. Compared to the other study groups, patients with temporal lobe epilepsy due to hippocampal sclerosis showed a basal olfactory dysfunction characterized by an impairment in odor discrimination and odor identification. We also found that high seizure frequency had a strong correlation with the evaluated olfactory tasks. Our results are consistent with neuroimaging and neuropathological data that establish a link between olfactory regions and the pathophysiology of temporal lobe epilepsy.
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Affiliation(s)
- Camilo Espinosa‐Jovel
- Epilepsy Unit, Department of NeurologyHospital Occidente de KennedyBogotáColombia
- Epilepsy Unit, Department of NeurologyHospital Ruber InternacionalMadridSpain
| | - Rafael Toledano
- Epilepsy Unit, Department of NeurologyHospital Ruber InternacionalMadridSpain
- Epilepsy Unit, Department of NeurologyHospital Ramón y CajalMadridSpain
| | - Adolfo Jiménez‐Huete
- Clinical Neurology Unit, Department of NeurologyHospital Ruber InternacionalMadridSpain
| | - Ángel Aledo‐Serrano
- Epilepsy Unit, Department of NeurologyHospital Ruber InternacionalMadridSpain
| | - Irene García‐Morales
- Epilepsy Unit, Department of NeurologyHospital Ruber InternacionalMadridSpain
- Epilepsy Unit, Department of NeurologyHospital Clínico San CarlosMadridSpain
| | - Pablo Campo
- Department of Basic PsychologyAutonomous University of MadridMadridSpain
| | - Antonio Gil‐Nagel
- Epilepsy Unit, Department of NeurologyHospital Ruber InternacionalMadridSpain
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Abstract
This chapter focuses on the development of the human olfactory system. In this system, function does not require full neuroanatomical maturity. Thus, discrimination of odorous molecules, including a number within the mother's diet, occurs in amniotic fluid after 28-30 weeks of gestation, at which time the olfactory bulbs are identifiable by MRI. Hypoplasia/aplasia of the bulbs is documented in the third trimester and postnatally. Interestingly, olfactory axons project from the nasal epithelium to the telencephalon before formation of the olfactory bulbs and lack a peripheral ganglion, but the synaptic glomeruli of the future olfactory bulb serves this function. Histologic lamination of the olfactory bulb is present by 14 weeks, but maturation remains incomplete at term for neuronal differentiation, synaptogenesis, myelination, and persistence of the normal transitory fetal ventricular recess. Myelination occurs postnatally. Although olfaction is the only sensory system without direct thalamic projections, the olfactory bulb and anterior olfactory nucleus are, in effect, thalamic surrogates. For example, many dendro-dendritic synapses occur within the bulb between GABAergic granular neurons and periglomerular neurons. Moreover, bulbar synaptic glomeruli are analogous to peripheral ganglia of other sensory cranial nerves. The olfactory tract contains much gray as well as white matter. The olfactory epithelium and bulb both incorporate progenitor cells at all ages. Diverse malformations of the olfactory bulb can be detected by clinical examination, imaging, and neuropathology; indeed, olfactory reflexes of the neonate can be reliably tested. We recommend that such testing be routine in the neonatal neurologic examination, especially in children with brain malformations, endocrinopathies, chromosomopathies, genetic/metabolic disorders, and perinatal hypoxic/ischemic encephalopathy.
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Affiliation(s)
- Harvey B Sarnat
- Department of Paediatrics, University of Calgary Cumming School of Medicine and Alberta Children's Hospital Research Institute, Calgary, AB, Canada; Department of Clinical Neurosciences, University of Calgary Cumming School of Medicine and Alberta Children's Hospital Research Institute, Calgary, AB, Canada; Department of Pathology and Laboratory Medicine (Neuropathology), University of Calgary Cumming School of Medicine and Alberta Children's Hospital Research Institute, Calgary, AB, Canada.
| | - Laura Flores-Sarnat
- Department of Paediatrics, University of Calgary Cumming School of Medicine and Alberta Children's Hospital Research Institute, Calgary, AB, Canada; Department of Clinical Neurosciences, University of Calgary Cumming School of Medicine and Alberta Children's Hospital Research Institute, Calgary, AB, Canada
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12
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Rhinencephalon changes in tuberous sclerosis complex. Neuroradiology 2018; 60:813-820. [PMID: 29909560 DOI: 10.1007/s00234-018-2045-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Accepted: 06/01/2018] [Indexed: 10/14/2022]
Abstract
PURPOSE Despite complex olfactory bulb embryogenesis, its development abnormalities in tuberous sclerosis complex (TSC) have been poorly investigated. METHODS Brain MRIs of 110 TSC patients (mean age 11.5 years; age range 0.5-38 years; 52 female; 26 TSC1, 68 TSC2, 8 without mutation identified in TSC1 or TSC2, 8 not tested) were retrospectively evaluated. Signal and morphological abnormalities consistent with olfactory bulb hypo/aplasia or with olfactory bulb hamartomas were recorded. Cortical tuber number was visually assessed and a neurological severity score was obtained. Patients with and without rhinencephalon abnormalities were compared using appropriate parametric and non-parametric tests. RESULTS Eight of110 (7.2%) TSC patients presented rhinencephalon MRI changes encompassing olfactory bulb bilateral aplasia (2/110), bilateral hypoplasia (2/110), unilateral hypoplasia (1/110), unilateral hamartoma (2/110), and bilateral hamartomas (1/110); olfactory bulb hypo/aplasia always displayed ipsilateral olfactory sulcus hypoplasia, while no TSC patient harboring rhinencephalon hamartomas had concomitant forebrain sulcation abnormalities. None of the patients showed overt olfactory deficits or hypogonadism, though young age and poor compliance hampered a proper evaluation in most cases. TSC patients with rhinencephalon changes had more cortical tubers (47 ± 29.1 vs 26.2 ± 19.6; p = 0.006) but did not differ for clinical severity (p = 0.45) compared to the other patients of the sample. CONCLUSIONS Olfactory bulb and/or forebrain changes are not rare among TSC subjects. Future studies investigating clinical consequences in older subjects (anosmia, gonadic development etc.) will define whether rhinencephalon changes are simply an imaging feature among the constellation of TSC-related brain changes or a feature to be searched for possible implications in the management of TSC subjects.
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Tunsuriyawong P, Pongpirul K, Chaisam T, Prajuabpansri P. Olfactory bulb agenesis with normal sexual hormones. BMJ Case Rep 2017; 2017:bcr-2017-221899. [PMID: 29025782 DOI: 10.1136/bcr-2017-221899] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
An 18-year-old Caucasian man presented with a lack of sense of surrounding smell. The problem was first noticed when a family member discussed the smell of the food, which he had no idea what it was. The patient had normal development and sexual function, no history of trauma, surgery, chemical exposure or infection. Physical examination revealed no significant abnormalities. Smell threshold test using phenyl-ethyl-alcohol revealed bilateral anosmia. MRI showed bilateral aplastic olfactory bulbs and tracts associated with absent cortical growth of the olfactory sulci and asymmetrical gyrus rectus. Circulating hormones including cortisol, growth hormone, insulin-like growth factor 1, adrenocorticotropic hormone, thyroid hormones, follicle-stimulating hormone, luteinizing hormone, prolactin and testosterone were within normal ranges. Doppler ultrasound showed normal testis with bilateral supratesticular varicoceles. Given the loss of warning smell sensation, counselling for daily living precautions especially those related to gas, fire and rotten food was given.
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Affiliation(s)
| | - Krit Pongpirul
- Department of Preventive and Social Medicine, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand.,Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Tagann Chaisam
- Neuroscience Center, Bumrungrad International Hospital, Bangkok, Thailand
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Sarnat HB, Flores-Sarnat L, Wei XC. Olfactory Development, Part 1: Function, From Fetal Perception to Adult Wine-Tasting. J Child Neurol 2017; 32:566-578. [PMID: 28424010 DOI: 10.1177/0883073817690867] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Discrimination of odorous molecules in amniotic fluid occur after 30 weeks' gestation; fetuses exhibit differential responses to maternal diet. Olfactory reflexes enable reliable neonatal testing. Olfactory bulbs can be demonstrated reliably by MRI after 30 weeks' gestation, and their hypoplasia or aplasia also documented by late prenatal and postnatal MRI. Olfactory axons project from nasal epithelium to telencephalon before olfactory bulbs form. Fetal olfactory maturation remains incomplete at term for neuronal differentiation, synaptogenesis, myelination, and persistence of the transitory fetal ventricular recess. Immaturity does not signify nonfunction. Olfaction is the only sensory system without thalamic projection because of its own intrinsic thalamic equivalent. Diverse malformations of the olfactory bulb can be diagnosed by clinical examination, imaging, and neuropathology. Some epileptic auras might be primarily generated in the olfactory bulb. Cranial nerve 1 should be tested in all neonates and especially in patients with brain malformations, endocrinopathies, chromosomopathies, and genetic/metabolic diseases.
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Affiliation(s)
- Harvey B Sarnat
- 1 Department of Paediatrics, University of Calgary Cumming School of Medicine, Calgary, Alberta, Canada.,2 Department of Clinical Neurosciences, University of Calgary Cumming School of Medicine, Calgary, Alberta, Canada.,3 Department of Pathology and Laboratory Medicine (Neuropathology), University of Calgary Cumming School of Medicine, Calgary, Alberta, Canada.,5 Alberta Children's Hospital Research Institute, Calgary, Alberta, Canada
| | - Laura Flores-Sarnat
- 1 Department of Paediatrics, University of Calgary Cumming School of Medicine, Calgary, Alberta, Canada.,2 Department of Clinical Neurosciences, University of Calgary Cumming School of Medicine, Calgary, Alberta, Canada.,3 Department of Pathology and Laboratory Medicine (Neuropathology), University of Calgary Cumming School of Medicine, Calgary, Alberta, Canada.,5 Alberta Children's Hospital Research Institute, Calgary, Alberta, Canada
| | - Xing-Chang Wei
- 4 Department of Radiology and Diagnostic Imaging, University of Calgary Cumming School of Medicine, Calgary, Alberta, Canada.,5 Alberta Children's Hospital Research Institute, Calgary, Alberta, Canada
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