A multimodal neuroimaging study of brain abnormalities and clinical correlates in post treatment Lyme disease

Neuropsychiatric Manifestations and Cognitive Decline in Patients With Long-Standing Lyme Disease: A Scoping Review

Lyme disease (LD), or Lyme borreliosis, is a vector-borne disease that is caused by the transmission of the bacterium Borrelia burgdorferi through a tick bite. The symptoms of LD can persist in individuals chronically, even after the treatment and resolution of the initial infection. These symptoms include various neuropsychiatric manifestations and cognitive decline. The purpose of this review was to report the neuropsychiatric manifestations, cognitive decline, and effects of a delayed diagnosis on symptom severity in patients with long-standing LD (LSLD). A scoping review was conducted utilizing the electronic databases Embase, Ovid Medical Literature Analysis and Retrieval System Online (MEDLINE), and Web of Science. A total of 744 articles were retrieved and considered for inclusion. After a rigorous screening process, 10 articles that met the inclusion criteria for this review were included (i.e., reported neuropsychiatric manifestations and cognitive decline in patients with LSLD and the effects of a delayed diagnosis). Neuropsychiatric manifestations in the patients consisted of suicidal ideation, homicidal tendencies, extreme anger, depressive symptoms, aggression, and anxiety. Cognitive symptoms included dysfunctions in working memory, verbal learning/memory, non-verbal learning/memory, alertness, visuoconstructive, and frontal executive functioning. A delayed LD diagnosis increased symptom severity in most patients. The findings of this review indicate that neuropsychiatric and cognitive symptoms tend to present for a chronic period, even after disease recovery. Although researchers have established a link between a delayed LD diagnosis and increased symptom severity, LSLD is often an overlooked diagnosis in patients with neuropsychiatric symptoms and cognitive decline. More research is needed to compare the time to diagnosis and symptom severity in patients with LSLD.

Parasitic manipulation or side effects? The effects of past Toxoplasma gondii and Borrelia spp. infections on human personality and cognitive performance are not mediated by impaired health

Bacteria Borrelia burgdorferi s. l. and even more the protist Toxoplasma gondii Nicolle et Manceaux, 1908, are known to affect the behaviour and mental health of their animal and human hosts. Both pathogens infect a significant fraction of human population, both are neurotropic and survive in the host's body for a long time. While latent infections were thought to be clinically asymptomatic, recent studies suggest otherwise, revealing adverse effects on human health. It was hypothesised that the specific behavioural effects of these pathogens may be side effects of general health impairments in infected individuals. This hypothesis was tested using about one hour-long survey consisting of questionnaires and performance tests on a cohort of 7,762 members of the internet population. Results showed that individuals infected with T. gondii reported worse physical and mental health, and those infected with Borrelia spp. reported worse physical health than uninfected controls. Furthermore, infected and noninfected individuals differed in several personality traits, including conscientiousness, pathogen disgust, injury disgust, Machiavellianism, narcissism, tribalism, anti-authoritarianism, intelligence, reaction time, and precision. While the majority of behavioural effects associated with Borrelia infection were similar to those associated with Toxoplasma infection, some differences were observed, such as performance in the Stroop test. Path analyses and nonparametric partial Kendall correlation tests showed that these effects were not mediated by impaired health in infected individuals, contradicting the side effects hypothesis.

Superior efficacy of combination antibiotic therapy versus monotherapy in a mouse model of Lyme disease

Lyme disease (LD) results from the most prevalent tick-borne infection in North America, with over 476,000 estimated cases annually. The disease is caused by Borrelia burgdorferi (Bb) sensu lato which transmits through the bite of Ixodid ticks. Most cases treated soon after infection are resolved by a short course of oral antibiotics. However, 10-20% of patients experience chronic symptoms because of delayed or incomplete treatment, a condition called Post-Treatment Lyme Disease (PTLD). Some Bb persists in PTLD patients after the initial course of antibiotics and an effective treatment to eradicate the persistent Bb is needed. Other organisms that cause persistent infections, such as M. tuberculosis, are cleared using a combination of therapies rather than monotherapy. A group of Food and Drug Administration (FDA)-approved drugs previously shown to be efficacious against Bb in vitro were used in monotherapy or in combination in mice infected with Bb. Different methods of detection were used to assess the efficacy of the treatments in the infected mice including culture, xenodiagnosis, and molecular techniques. None of the monotherapies eradicated persistent Bb. However, 4 dual combinations (doxycycline + ceftriaxone, dapsone + rifampicin, dapsone + clofazimine, doxycycline + cefotaxime) and 3 triple combinations (doxycycline + ceftriaxone+ carbomycin, doxycycline + cefotaxime+ loratadine, dapsone+ rifampicin+ clofazimine) eradicated persistent Bb infections. These results suggest that combination therapy should be investigated in preclinical studies for treating human Lyme disease.

Posttreatment Lyme disease syndrome and myalgic encephalomyelitis/chronic fatigue syndrome: A systematic review and comparison of pathogenesis

Lyme disease is the most common vector-borne illness in the United States and has been causing significant morbidity since its discovery in 1977. It is well-documented that about 10% of patients properly treated with antibiotics never fully recover, but instead go on to develop a chronic illness dubbed, posttreatment Lyme disease syndrome (PTLDS) characterized by severe fatigue, cognitive slowing, chronic pain, and sleep difficulties. This review includes 18 studies that detail the symptoms of patients with PTLDS and uses qualitative analysis to compare them to myalgic encephalitis/chronic fatigue syndrome (ME/CFS), a strikingly similar syndrome. In the majority of the PTLDS studies, at least four of the six major symptoms of ME/CFS were also noted, including substantial impairment in activity level and fatigue for more than 6 months, post-exertional malaise, and unrefreshing sleep. In one of the included PTLDS articles, 26 of the 29 ME/CFS symptoms were noted. This study adds to the expanding literature on the post-active phase of infection syndromes, which suggests that chronic illnesses such as PTLDS and ME/CFS have similar pathogenesis despite different infectious origins.

An fMRI analysis of verbal and non-verbal working memory in people with a past history of opioid dependence

Introduction

Working memory describes the ability to maintain and manipulate information held in mind, and it is a fundamental aspect of executive function. Within drug addiction, impairments of executive control over behavior are thought to lead to poor decision making and risky behaviors. Previous research has demonstrated working memory (WM) and executive function difficulties in opioid-dependent individuals, but the neural underpinnings of such impairments in this population are not well understood.

Methods

This study used functional magnetic resonance imaging to examine the neural mechanisms involved in WM in 13 opioid-dependent, methadone-maintained participants (OP) and 13 matched, healthy controls (HC). A Sternberg item-recognition task was administered with three conditions: (1) a "verbal" condition in which participants determined whether any six visually presented target letters matched a probe item that was presented 4-6 s later, (2) a "non-verbal" condition in which participants were presented with a Chinese character and, following a 4-6 s delay, determined whether the character matched the probe item, and (3) a "control" condition in which participants were presented with three horizontal lines and following the same delay, determined whether the lines matched a probe item (always the same three lines). Functional magnetic resonance imaging (fMRI) contrasts focused on the delay (or "maintenance") phase for verbal and non-verbal conditions relative to the control condition.

Results

Accuracy on the WM task did not differ between groups, but the OP group was significantly slower to respond. The fMRI imaging results indicated differences in brain activity between the OP and HC groups. fMRI-guided regions of interest correlated with age of first alcohol and THC use, suggesting that early substance use, in addition to years of opioid-abuse, may have played a role in the OP group's WM performance.

Discussion

A deeper understanding of these neural differences between opioid-dependent individuals and their healthy control counterparts helps shed light on fundamental ways in which substance use impacts the brain and cognition, potentially opening up novel avenues for therapeutic targets to treat substance use disorder.