The progression of coeliac disease: its neurological and psychiatric implications

Childhood Apraxia of Speech: Exploring Gluten Sensitivity and Changes in Glutamate and Gamma-Aminobutyric Acid Plasma Levels

BACKGROUND

Individuals with childhood apraxia of speech (CAS) were reported to have genetic variations related to gluten sensitivity and some neuroanatomic changes, which could be associated with alterations in neurotransmitters levels such as glutamate and gamma-aminobutyric acid (GABA). The aim was to measure the levels of antigliadin immunoglobulin A (IgA) antibody, glutamate, and GABA in the plasma of children with CAS compared with children with delayed language development (DLD) and neurotypical (NT) children.

METHODS

The participants (N = 120) were in three groups: Group I for CAS (N = 30), Group II for DLD (N = 60), and Group III for NT (N = 30). The abilities of children in Groups I and II were evaluated. The plasma levels of antigliadin IgA, glutamate, and GABA were determined by enzyme-linked immunosorbent assay.

RESULTS

The intelligence quotient and expressive language age in Group I were low compared with Group II (P = 0.001; 0.004). The levels of antigliadin IgA and glutamate in Group I were higher compared with the other two groups, whereas the level of GABA was lower (P < 0.0001). An imbalance between glutamate and GABA was found in Group I. In Group II, no measures differed from NTs except lower GABA levels (P = 0.0007).

CONCLUSIONS

The elevated levels of antigliadin IgA antibody and glutamate demonstrated high sensitivity and specificity, differentiating children with CAS from children with DLD and NT children. The low levels of GABA contributed to the imbalance between the excitatory and inhibitory neurotransmitters' levels detected in children with CAS.

The Exploration of the Eating Experience in Adults with Celiac Disease: A Phenomenological Qualitative Study

BACKGROUND

The adjustment to a strict gluten-free diet for adults diagnosed with celiac disease (CD) may lead to changes in the eating experience affecting the physical, social, and emotional states.

OBJECTIVE

Through the application of the Social Cognitive Transition Model of Adjustment, the aim of the study was to explore the adjustment in the eating experience in adults recently diagnosed with CD and transitioning to a gluten-free diet.

DESIGN

This was a qualitative phenomenological study conducted using semistructured interviews.

PARTICIPANTS AND SETTING

Seventeen adults from the midwestern United States who were diagnosed with CD between 6 months and 5 years before the study were recruited using social media CD sites and snowball sampling. Participants completed a semistructured interview on Zoom and the Celiac Disease Adherence Test and CeliacQ-7 questionnaires from May to November 2020.

STATISTICA ANALYSES PERFORMED

Two trained qualitative researchers engaged in four steps to reduce and contextualize the data: horizontilization, reduction and elimination, clustering and thematizing, and composition of textural description. During analysis, the Social Cognitive Transition Model of Adjustment was incorporated for organization of themes and text description.

RESULTS

There was moderate to high dietary adherence in 14 of 17 participants and quality of life scores ranged from 19 to 43 (median = 33). Five themes emerged aligning with Social Cognitive Transition Model of Adjustment, describing the adjustment in pre- and postdiagnosis eating experience and the coping and behaviors enacted during adjustment to a gluten-free diet.

CONCLUSIONS

In individuals with CD, moving beyond problem solving and identifying psychosocial and emotional attributes in the adoption of a gluten-free diet need to be considered to promote maintenance of quality of life and dietary adherence.

A Clinical Investigation on ADHD-Traits in Childhood Celiac Disease

OBJECTIVE

There are no definitive results about either the presence of exact comorbidity between celiac disease (CD) and attention-deficit/hyperactivity disorders (ADHD) or etiology. We intend to screen ADHD-related cognitive and behavioral traits in children with biopsy-proven CD and investigate the possible association of these traits with certain vitamin levels, body-mass index, and gluten-free diet (GFD) compliance.

METHOD

A total of 85 children with biopsy-proven CD (the ages of 8-18 years) were compared with age and sex-matched 72 healthy controls in terms of demographics, psychiatric symptoms, certain vitamin levels, and anthropometric measurements.

RESULTS

ADHD-like cognitive issues, such as inattention and learning difficulties, as well as psychosomatic symptoms and poor prosocial behavior, were all associated with GFD noncompliance in childhood CD.

CONCLUSION

Untreated CD may predispose to ADHD-resembling symptoms. Physicians should be aware of the probability of ADHD misdiagnosing due to ADHD-resembling cognitive and behavioral traits in untreated CD.

Epilepsy, Immunity and Neuropsychiatric Disorders

Several studies have focused on the emerging role of immunity and inflammation in a wide range of neurological disorders. Autoimmune diseases involving central nervous system share well defined clinical features including epileptic seizures and additional neuropsychiatric symptoms, like cognitive and psychiatric disturbances. The growing evidence about the role of immunity in the pathophysiologic mechanisms underlying these conditions lead to the concept of autoimmune epilepsy. This relatively-new term has been introduced to highlight the etiological and prognostic implications of immunity in epileptogenesis. In this review, we aim to discuss the role of autoimmunity in epileptogenesis and its clinical, neurophysiological, neuroimaging and therapeutic implications. Moreover, we wish to address the close relationship between immunity and additional symptoms, particularly cognitive and psychiatric features, which deeply impact clinical outcomes in these patients. To assess these aspects, we first analyzed Rasmussen's encephalitis. Subsequently, we have covered autoimmune encephalitis, particularly those associated with autoantibodies against surface neuronal antigens, as these autoantibodies express a direct immune-mediated mechanism, different from those against intracellular antigens. Then, we discussed the connection between systemic immune disorders and neurological manifestations. This review aims to highlight the need to expand knowledge about the role of inflammation and autoimmunity in the pathophysiology of neurological disorders and the importance to early recognize these clinical entities. Indeed, early identification may result in faster recovery and a better prognosis.

Celiac Disease and Neurological Manifestations: From Gluten to Neuroinflammation

Celiac disease (CD) is a complex multi-organ disease with a high prevalence of extra-intestinal involvement, including neurological and psychiatric manifestations, such as cerebellar ataxia, peripheral neuropathy, epilepsy, headache, cognitive impairment, and depression. However, the mechanisms behind the neurological involvement in CD remain controversial. Recent evidence shows these can be related to gluten-mediated pathogenesis, including antibody cross-reaction, deposition of immune-complex, direct neurotoxicity, and in severe cases, vitamins or nutrients deficiency. Here, we have summarized new evidence related to gut microbiota and the so-called "gut-liver-brain axis" involved in CD-related neurological manifestations. Additionally, there has yet to be an agreement on whether serological or neurophysiological findings can effectively early diagnose and properly monitor CD-associated neurological involvement; notably, most of them can revert to normal with a rigorous gluten-free diet. Moving from a molecular level to a symptom-based approach, clinical, serological, and neurophysiology data might help to disentangle the many-faceted interactions between the gut and brain in CD. Eventually, the identification of multimodal biomarkers might help diagnose, monitor, and improve the quality of life of patients with "neuroCD".

Cerebellar Symptoms in Gluten Sensitivity: a Systematic Review of the Effect of a Gluten-Free Diet on Brain Imaging

Cerebellar manifestations have been described in patients with gluten sensitivity (GS)-related disorders. A better understanding of the neurological manifestations of GS requires the use of neuroimaging techniques. We performed a systematic review on neuroimaging findings in GS patients with cerebellar symptoms. We also included a specific search on neuroimaging findings in GS patients with cerebellar manifestations on a gluten-free diet (GFD). PubMed, Embase, and Bireme were systematically searched to identify studies assessing neuroimaging features of adults with cerebellar manifestations and GS with or without enteropathy on a GFD. Ten studies with a total of 222 adult-GS patients were included. Magnetic resonance imaging was used in 100% of the studies. Cerebellar atrophy was evaluated in 7 studies and observed in 63% of the patients. White matter abnormalities were described in 2 studies. Single-photon emission computed tomography was used in 2 studies, and decreased cerebellar perfusion was detected in 92% of the included patients. No study employed nuclear medicine after the start of GFD. Magnetic resonance spectroscopy (MRS) was performed in 2 studies before and after GFD. An increase in the Naa/Cr ratio in cerebellar vermis was seen in 98% of the cases on a strict GFD. Cerebellar atrophy was found to be a prevalent condition in GS patients. MRS demonstrated to be useful in the follow-up of GS patients with cerebellar manifestations on a GFD. Prospective studies using nuclear medicine imaging are needed to study brain changes in GS patients on a GFD.

Gliadin-reactive vitamin D-sensitive proinflammatory ILCPs are enriched in celiac patients

Celiac disease (CD) is a multisystem disease in which different organs may be affected. We investigate whether circulating innate lymphoid cells (ILCs) contribute to the CD peripheral inflammatory status. We find that the CD cytokine profile is characterized by high concentrations of IL-12p40, IL-18, and IFN-γ, paralleled by an expansion of ILC precursors (ILCPs). In the presence of the gliadin peptides p31-43 and pα-9, ILCPs from CD patients increase transglutaminase 2 (TG2) expression, produce IL-18 and IFN-γ, and stimulate CD4⁺ T lymphocytes. IFN-γ is also produced upon stimulation with IL-12p40 and IL-18 and is inhibited by the addition of vitamin D. Low levels of blood vitamin D correlate with high IFN-γ and ILCP presence and mark the CD population mostly affected by extraintestinal symptoms. Dietary vitamin D supplementation appears to be an interesting therapeutic approach to dampen ILCP-mediated IFN-γ production.

Extra-Intestinal Manifestations of Celiac Disease: What Should We Know in 2022?

Celiac disease (CD) is a chronic, small-intestinal, immune-mediated enteropathy due to gluten exposition in genetically predisposed individuals. It occurs in about 1% of the population and often remains an underdiagnosed condition. This could be due to the fact that the adult population often lacks the classical signs and symptoms of CD, manifesting only atypical symptoms. In this review we analyzed the main extra-intestinal manifestations of CD which include cutaneous and endocrinological disorders, abnormal liver function tests, and neuropsychiatric features. When CD is not diagnosed and therefore is not treated with a gluten-free diet (GFD), it can predispose to severe complications, not only gastrointestinal. Thus, it is important for clinicians to quickly recognize the atypical manifestations of CD, considering that an early diagnosis can significantly impact on a patient's prognosis.

A Neurological Appearance of Celiac Disease: Is There Any Associated Factor?

OBJECTIVE

Celiac disease may present with one or more neurological signs and/or symptoms. We aimed to define the incidence of accompanying neurological manifestations in children diagnosed as having celiac disease.

METHODS

The prospective study included 146 children diagnosed as having celiac disease. The medical records (presentation symptoms, clinical findings, serological test, duodenal biopsy results, lack/deficiency of vitamin, tissue type, accompanying autoimmune disorders) and demographic data of all patients were also reviewed.

RESULTS

Thirty-five (23.9%) of the 146 celiac patients exhibited one or more neurological findings. Headache (11.6%) and dizziness (6.1%) were the most common symptoms among neurological manifestations. There was a significant difference between the patients with and without neurological manifestations in terms of sex, biopsy result, and tissue type (P < 0.05). Moreover, there was a statistically significant difference between tissue types of the patients with and without headache (P < 0.05). We found that grade 3a by Marsh classification was the most common type among the patients with and without neurological findings in celiac disease. On neuroimaging evaluation of patients, 1 patient with chronic focal ischemic lesion, 1 patient with Chiari type 1 malformation, and 1 patient with subcortical white matter changes were identified.

CONCLUSIONS

Pathophysiology of neurological involvement in celiac disease is liable for various neurological findings. This study contributes to data suggesting that female sex, mild histopathological form, and human leukocyte antigen DQ2 heterozygosity are related to neurological manifestations, and also human leukocyte antigen DQ2 heterozygosity is associated with headache in celiac disease.

Coeliac disease is associated with depression in children and young adults with type 1 diabetes: results from a multicentre diabetes registry

AIMS

To analyse the association between coeliac disease (CD) and depression in children, adolescents, and young adults with type 1 diabetes (T1D).

METHODS

We included 79,067 T1D patients aged 6-20 years, with at least six months of diabetes duration, and treatment data between 1995 and 2019 were documented in the diabetes patient follow-up registry. We categorized patients into four groups: T1D only (n = 73,699), T1 + CD (n = 3379), T1D + depression (n = 1877), or T1D + CD + depression (n = 112).

RESULTS

CD and depression were significantly associated (adjusted OR: 1.25 [1.03-1.53]). Females were more frequent in both the depression and the CD group compared with the T1D only group. Insulin pumps were used more frequently in T1D + CD and T1D + depression compared with T1D only (both p < .001). HbA1c was higher in T1D + depression (9.0% [8.9-9.0]), T1D + CD + depression (8.9% [8.6-9.2]), both compared with T1D only (8.2% [8.2-8.2], all p < .001). We found comorbid autism, attention deficit hyperactivity disorder, anxiety, schizophrenia, and eating disorders more frequently in the T1D + CD + depression group compared with T1D only (all p < .001).

CONCLUSIONS

CD and depression are associated in young T1D patients. The double load of T1D and CD may lead to an increased risk for depression. Depression was associated with additional psychological and neurological comorbidities. Aside from imperative CD screening after T1D diagnosis and regular intervals, depression screening might be helpful in routine care, especially in patients with diagnosed CD.

What is the role of small bowel capsule endoscopy in established coeliac disease?

INTRODUCTION

Patients with established coeliac disease (CD) can present with signs and symptoms requiring small bowel capsule endoscopy (SBCE) to assess for persistent disease beyond the duodenum and to rule out complications. There is paucity of data on extent of disease on SBCE in relation to histology, clinical and serological parameters. The aim of this study was to assess the relationship between symptoms, CD serology and Marsh classification of disease and extent of disease on SBCE in patients with established CD.

METHODS

Hundred patients with established CD and 200 controls underwent a SBCE. SBCEs were reviewed by expert reviewers. Extent of disease on SBCE, CD findings and small bowel transit were recorded.

RESULTS

Considering duodenal histology (D2; Marsh 3a or above) as the gold standard for diagnosing CD activity, the sensitivity of SBCE to delineate active disease was 87.2%. The specificity was 89.0%. Age at SBCE (P=0.006), albumin (P=0.004) and haemoglobin (P=0.0001), Marsh score of histology from the duodenal bulb (D1) (P=0.0001) and the second part of the duodenum (P=0.0001), refractory CD (P=0.007) on histology correlated with extent of affected small bowel (SB) mucosa on univariate analysis. On multiple regression analysis, albumin (P=0.036) and Marsh score of histology (D1) (P=0.019), vitamin B12 (P=0.001) and folate levels (P=0.008) were statistically significant. Extent of affected SB mucosa (11.0% vs 1.35%) was greater in patients with complications including those with refractory CD (P=0.008).

CONCLUSIONS

This is the first study showing correlation between extent of disease and severity of duodenal histology, markers of malabsorption such as folate levels and vitamin B12 and complications of CD.

Celiac Disease Diagnosed in an Older Adult Patient with a Complex Neuropsychiatric Involvement: A Case Report and Review of the Literature

We present a case of celiac disease (CD) diagnosis in a 75-year-old woman with a long-term history of chronic delusional jealousy and a complex neurological involvement. The case describes a very unusual clinical picture, provides some clinical clues, and highlights the importance of being aware of CD extraintestinal manifestations in order to get a timely diagnosis.

Anxiety Symptoms in Adult Celiac Patients and the Effect of a Gluten-Free Diet: An Iranian Nationwide Study

Introduction

Psychiatric disorders, especially anxiety, are considered extraintestinal manifestations of celiac disease (CD).

Objective

This study aims to evaluate the level of anxiety in treated patients with CD in Iran.

Methods

A total of 283 CD patients (190 female, 93 male) were enrolled in a study during 2016-2018 from 9 centers in Iran. The Zung Self-Rating Anxiety Scale questionnaire was completed. The anxiety index was calculated. Also, demographic data and the duration of treatment with a gluten-free diet (GFD) were recorded. Data were analyzed by SPSS version 20.

Results

Anxiety symptoms were reported in 67.8% of patients. Female patients had a higher anxiety index than male patients. Duration of treatment with a GFD did not influence the anxiety index (17.3% were on a GFD for <1 year, 33.6% for 1-2 years, and 49.1% had GFD for >2 years; p = 0.86).

Conclusions

These results suggest that anxiety symptoms are common among patients, especially females, with CD in Iran and GFD duration has no effect on their improvement.

Lactobacillus Rhamnosus GG Affects the BDNF System in Brain Samples of Wistar Rats with Pepsin-Trypsin-Digested Gliadin (PTG)-Induced Enteropathy

Celiac disease (CD) presents as chronic low-grade inflammation of the small intestine often characterized by psychiatric comorbidities. The brain-derived neurotrophic factor (BDNF), which we have shown to be reduced in the serum of CD patients, acts as the bridge between immune activation and the nervous system adaptive response. Since Lactobacillus has been shown to upregulate BDNF, this study aimed to evaluate whether the administration of Lactobacillus rhamnosus GG (L.GG) could positively affect the brain BDNF system in rats mimicking the CD lesions. Data have shown that the administration of pepsin-trypsin digested gliadin (PTG) and L.GG alter the levels of mature BDNF (mBDNF), as evaluated by Western blotting. PTG provoked a reduction of mBDNF compared to controls, and a compensatory increase of its receptor TrkB. L.GG induced a slight positive effect on mBDNF levels under normal conditions, while it was able to rescue the PTG-induced reduced expression of mBDNF. The curative effect of L.GG was finely tuned, accompanied by the reduction of TrkB, probably to avoid the effect of excessive BDNF.

Neuropsychiatric manifestations in celiac disease

Celiac disease (CD) is a systemic, chronic immune-mediated disorder elicited by gluten and related prolamines in genetically susceptible subjects. Main manifestations of CD involve the digestive tract; however, a growing body of evidence supports the theory that symptoms may occur in every part of the body. It is known that some patients with CD can be asymptomatic, and additionally, the incidence of "nonclassical" CD with extraintestinal presentation is apparently increasing. We aimed to perform a thorough review of existing evidence for neurological manifestations of CD, providing an up-to-date description of prevalence and examining the pathogenetic mechanisms possibly involved. Neurological presentations are rare in children but as many as 36% of adult patients present with neurological findings. With severe malnutrition after progression of CD, different vitamin deficiencies may develop. Such problems can in turn overlap with previous neurological abnormalities including ataxia, epilepsy, neuropathy, dementia, and cognitive disorders. Here, the most prevalent clinical manifestations in adults and children have been discussed in further detail. Further research is needed to achieve a complete understanding of the nervous system involvement in CD, but clinicians should always remember that neurological and psychiatric symptoms might be part of the CD spectrum of manifestations.

Insights in the Evaluation of Gluten Dietary Avoidance in Healthy Subjects

Background: The amount of healthy subjects adopting a gluten-free diet (GFD) for nonmedical reasons actually surpasses the numbers of those who are dealing with a permanent gluten-related disorder.Objective: The study aimed to better clarify the interactions between a GFD and physical and psychological well-being.Methods: Sixty healthy subjects with normal weight were enrolled. Thirty subjects (15 female) were submitted to a normocaloric GFD and considered as the experimental group (EG), and 30 subjects (15 female) were submitted to a normocaloric diet (CG) for 6 months. The hematochemical and psychological parameters before and after the diet were recorded.Results: Significant improvement was demonstrated in red blood count, hemoglobin, total cholesterol, and high-density lipoprotein parameters in the EG after the gluten-free diet. However, a significant increase of α-amylase pancreatic activity and reduction of vitamin B12 and magnesium levels in the EG were observed. Regarding the psychological parameters, the GFD significantly improved scores assessing body satisfaction, but increased social insecurity.Conclusions: The study is the first to consider significant modulation in hematochemical parameters as well as psychological ones by gluten avoidance in healthy individuals. Although these subjects were not characterized by intestinal mucosa damage, some of the effects were similar to those observed in celiac disease patients who began to adhere to a GFD.

Attention deficit and hyperactivity disorder symptoms respond to gluten-free diet in patients with coeliac disease

Introduction: Patients with coeliac disease commonly report symptoms of 'brain fog'. The aim of this study was to assess self-reported symptoms of impaired concentration in coeliac disease before and after treatment with gluten-free diet, compared with healthy controls and patient controls. Methods: Patients with newly diagnosed coeliac disease were included consecutively from two out-patient clinics. The patients completed the questionnaires Adult ADHD Self-Report Scale v1.1 Symptoms Checklist (ASRS), Hospital Anxiety and Depression Scale (HADS) and Gastrointestinal Symptom Rating Scale (GSRS) prior to start of a gluten-free diet and after at least 12 months on the diet. Patients with an established diagnosis of inflammatory bowel disease served as patient controls (n = 36). Health care personnel at Oslo University Hospital served as healthy controls (n = 60) and filled out ASRS and HADS. Results: A total of 31 newly diagnosed coeliac patients were included in the study. Of these, 26 patients met for follow-up and repeated the questionnaires. Prior to treatment, patients with coeliac disease had significantly higher scores than healthy controls on both the ASRS (p = .0014) and HADS (p=.0004). After a gluten-free diet, their scores improved and were not significantly different from healthy controls. There were no significant differences between patients with coeliac disease prior to treatment and patient controls with inflammatory bowel disease. Conclusion: Prior to treatment, coeliac disease patients reported significantly more symptoms than healthy controls on ASRS and HADS. The differences disappeared after a minimum of 12 months on a gluten-free diet.

Cognitive Impairment and Celiac Disease: Is Transcranial Magnetic Stimulation a Trait d'Union between Gut and Brain?

Celiac disease is a systemic disorder with multifactorial pathogenesis and multifaceted symptomatology. In response to gluten exposure, a significant part of the general population produces antibodies that have been hypothesized to be deleterious to the brain. Among the well-known neurological manifestations, adult celiac patients often complain cognitive symptoms, ranging from the so-called "brain fog" till an overt dementia. Transcranial magnetic stimulation (TMS) is a non-invasive brain stimulation technique that can contribute to the assessment and monitoring of celiac patients, even in those without a clear neurological involvement. The studies here reviewed seem to converge on an impaired central motor conductivity and a "hyperexcitable celiac brain" to TMS, which partially reverts back after a long-term gluten restriction. Notably, a clear hyperexcitability is a stably reported feature of both degenerative and vascular dementia. Therefore, given its potential neuroprotective effect, the gluten-free diet should be introduced as early as possible, although the overall response of neurological symptoms (and cognition in particular) is still controversial. Identifying new and possibly modifiable risk factors may be of crucial importance for patients, clinicians, and researchers.

Cognitive Impairment and Celiac Disease: Is Transcranial Magnetic Stimulation a Trait d'Union between Gut and Brain?

Celiac disease is a systemic disorder with multifactorial pathogenesis and multifaceted symptomatology. In response to gluten exposure, a significant part of the general population produces antibodies that have been hypothesized to be deleterious to the brain. Among the well-known neurological manifestations, adult celiac patients often complain cognitive symptoms, ranging from the so-called "brain fog" till an overt dementia. Transcranial magnetic stimulation (TMS) is a non-invasive brain stimulation technique that can contribute to the assessment and monitoring of celiac patients, even in those without a clear neurological involvement. The studies here reviewed seem to converge on an impaired central motor conductivity and a "hyperexcitable celiac brain" to TMS, which partially reverts back after a long-term gluten restriction. Notably, a clear hyperexcitability is a stably reported feature of both degenerative and vascular dementia. Therefore, given its potential neuroprotective effect, the gluten-free diet should be introduced as early as possible, although the overall response of neurological symptoms (and cognition in particular) is still controversial. Identifying new and possibly modifiable risk factors may be of crucial importance for patients, clinicians, and researchers.

Neurophysiology of the "Celiac Brain": Disentangling Gut-Brain Connections

Celiac disease (CD) can be considered a complex multi-organ disorder with highly variable extra-intestinal, including neurological, involvement. Cerebellar ataxia, peripheral neuropathy, seizures, headache, cognitive impairment, and neuropsychiatric diseases are complications frequently reported. These manifestations may be present at the onset of the typical disease or become clinically evident during its course. However, CD subjects with subclinical neurological involvement have also been described, as well as patients with clear central and/or peripheral nervous system and intestinal histopathological disease features in the absence of typical CD manifestations. Based on these considerations, a sensitive and specific diagnostic method that is able to detect early disease process, progression, and complications is desirable. In this context, neurophysiological techniques play a crucial role in the non-invasive assessment of central nervous system (CNS) excitability and conductivity. Moreover, some of these tools are known for their valuable role in early diagnosis and follow-up of several neurological diseases or systemic disorders, such as CD with nervous system involvement, even at the subclinical level. This review provides an up-to-date summary of the neurophysiological basis of CD using electroencephalography (EEG), multimodal evoked potentials, and transcranial magnetic stimulation (TMS). The evidence examined here seems to converge on an overall profile of "hyperexcitable celiac brain," which partially recovers after institution of a gluten-free diet (GFD). The main translational correlate is that in case of subclinical neurological involvement or overt unexplained symptoms, neurophysiology could contribute to the diagnosis, assessment, and monitoring of a potentially underlying CD.

Neurophysiology of the "Celiac Brain": Disentangling Gut-Brain Connections

Celiac disease (CD) can be considered a complex multi-organ disorder with highly variable extra-intestinal, including neurological, involvement. Cerebellar ataxia, peripheral neuropathy, seizures, headache, cognitive impairment, and neuropsychiatric diseases are complications frequently reported. These manifestations may be present at the onset of the typical disease or become clinically evident during its course. However, CD subjects with subclinical neurological involvement have also been described, as well as patients with clear central and/or peripheral nervous system and intestinal histopathological disease features in the absence of typical CD manifestations. Based on these considerations, a sensitive and specific diagnostic method that is able to detect early disease process, progression, and complications is desirable. In this context, neurophysiological techniques play a crucial role in the non-invasive assessment of central nervous system (CNS) excitability and conductivity. Moreover, some of these tools are known for their valuable role in early diagnosis and follow-up of several neurological diseases or systemic disorders, such as CD with nervous system involvement, even at the subclinical level. This review provides an up-to-date summary of the neurophysiological basis of CD using electroencephalography (EEG), multimodal evoked potentials, and transcranial magnetic stimulation (TMS). The evidence examined here seems to converge on an overall profile of "hyperexcitable celiac brain," which partially recovers after institution of a gluten-free diet (GFD). The main translational correlate is that in case of subclinical neurological involvement or overt unexplained symptoms, neurophysiology could contribute to the diagnosis, assessment, and monitoring of a potentially underlying CD.