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

Abstract

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.

Association of oral dysbiosis with oral cancer development (Review)

“…Microbiota-induced epigenetic modulation. It has been widely demonstrated that environmental factors, including diet, lifestyle habits, and natural compounds, are responsible for both genetic and epigenetic alterations predisposing the development of several diseases, and have beneficial effects in preventing the development of chronic-degenerative disorders (133)(134)(135)(136)(137)(138)(139)(140). In particular, dietary intake and food consumption modulate several cellular and molecular processes acting in a multifactorial manner (141)(142)(143).…”

Facilitatory/inhibitory intracortical imbalance in REM sleep behavior disorder: early electrophysiological marker of neurodegeneration?

“…25 Different paradigms of stimulation are applied to obtain a direct measure of cortical excitability and, indirectly, to gain information regarding the functioning of underlying neurotransmitter systems 26,27 in neurological and psychiatric conditions, [28][29][30][31][32][33] as well as in systemic diseases with central nervous system (CNS) involvement. [34][35][36][37][38] Several variables, such as the resting motor threshold (rMT), the cortical silent period (CSP), the latency and the amplitude of motor evoked potentials (MEPs), and the central motor conduction time (CMCT), are assessed by means of the single-pulse technique. 26 Paired-pulse technique allows the measurement of more sensible indexes of intracortical functioning, namely the short-interval intracortical inhibition (SICI) and the intracortical facilitation (ICF), 26 thus providing physiological insights on the cortical circuitry activated by TMS.…”

Update on the Neurobiology of Vascular Cognitive Impairment: From Lab to Clinic

“…The few TMS studies in CADASIL converge on a profile of cortical hyperexcitability, probably due to a glutamatergic and GABAergic dysfunction, as observed in other dementias [79,80,102,103]. More recently, SAI was found significantly reduced both in AD and CADASIL, although the administration of levo-3,4-dihydroxyphenylalanine (L-DOPA) increased it in the AD group only, thus hypothesizing that the relationship between acetylcholine and dopamine systems may be specifically abnormal in AD only [46].…”

“…Among neurophysiological techniques, TMS is a non-invasive tool evaluating cortical excitability, synaptic plasticity, and functional connectivity in vivo and in "real time", in physiological conditions [70][71][72] and in a number of psychiatric and neurological disorders [73][74][75][76][77][78], including cognitive impairment and dementia [42,49,79], also providing neurochemical insights [80][81][82][83].…”