Thomas J. Farrer

• PhD
• Professor (Assistant) at University of Idaho

This narrative review examines infectious diseases as modifiable risk factors for dementia, particularly in the context of an aging global population. As the prevalence of Alzheimer’s disease and related dementias is expected to rise, prevention has become increasingly important due to the limited efficacy of current treatments. Emerging evidence l...

Importance: When patients present with cognitive impairment, consults to neuropsychology can assist internists and psychiatrists in diagnosis, treatment planning, and determination of functional status. Neuropsychological evaluation and treatment have been shown to improve health outcomes and patient and family satisfaction. The objective of this n...

Neurodegenerative disease is a major global health problem with 150 million people predicted to have dementia by 2050. Genetic factors, environmental factors, demographics, and some diseases have been associated with dementia. In addition to associations between diseases such as hypertension and cerebrovascular disease and dementia, emerging findin...

Objective: Examine the association between neuropsychologically assessed executive function and clinically identifiable white matter burden from magnetic resonance imaging, using a visual rating system (Scheltens Rating System) applied to the Cache County Memory Study (CCMS) archival database. Method: We used the Scheltens Ratings Scale to quant...

Introduction Concussion in children and adolescents is a public health concern with higher concussion incidence than adults and increased susceptibility to axonal injury. The corpus callosum is a vulnerable location of concussion-related white matter damage that can be associated with short- and long-term effects of concussion. Interhemispheric tra...

In this case report,we describe the clinical characteristics of three older adults aged >65years with cognitive difficulties prior to theirCOVID-19 infection who reported worsening of neurocognitive symptoms in the convalescent COVID-19 phase. Formal neuropsychological testingalong with neuroimaging were included with each patient. These patients d...

As of March 2022, over 78 million cases of COVID-19 and 900,000 deaths have been reported in the United States. The consequences in the acute phase due to the SARS-COV-2 infection are well defined. Beyond the direct effects of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) involving the lung parenchyma, the post-viral complications wi...

Objective: White matter burden and medial temporal atrophy are associated with cognitive health. A large epidemiological database, such as the Cache County Memory Study (CCMS), can provide additional insight into how visual clinical ratings of brain structural integrity predict cognition in older adults. Method: We used the Scheltens Ratings Sca...

Diagnosis threat occurs when individuals have a negative expectation of behaviors or symptoms associated with a proposed diagnosis. For example, a member of a group may change their behavior or cognitive functioning because they are aware that such changes are typically expected of individuals in that group. In dementia, people may experience diagn...

Obstructive sleep apnea (OSA) is often associated with neuropsychological changes and cognitive impairment. While sleepiness and hypoxemia are both likely contributors to cognitive changes, the effects of OSA exceed what would be expected from these factors alone. Vascular changes related to hypertension and hyperlipidemia can play a role in the co...

Objective: Although cohort effects on IQ measures have been investigated extensively, studies exploring cohort differences on verbal memory tests, and the extent to which they are influenced by socioenvironmental changes across decades (e.g. educational attainment; ethnic makeup), have been limited. Method: We examined differences in performance be...

Deficits in attention and executive function appear to be fundamental aspects of attention-deficit, hyperactivity disorder, although impairment in executive function might not occur in all individuals who have attention-deficit, hyperactivity disorder. A crucial aspect of attention-deficit, hyperactivity disorder, though, is impairment in inhibitor...

Chronic pain is a common clinical condition that has a high lifetime prevalence, with significant morbidity and medical cost. An often overlooked aspect of chronic pain is the cognitive consequences. Findings on chronic pain and cognitive function reveal several important factors. First, patients with chronic pain appear to have worse cognitive fun...

Due to a combination of advancing medical technology and the increasing age of the adult population, more adults are pursuing surgical intervention, particularly elective surgery, than ever before. Postoperative cognitive decline (POCD) describes either a transient or chronic change in cognitive function that comes as a result of anesthesia or surg...

Some substances and prescribed medications appear to be associated with cognitive impairments across a variety of cognitive domains, although comparatively few studies address associations between drug use and cognitive function, and in some cases, the clinical importance of some of the associations between drug use and cognitive function remains u...

Most commonly thought of as an autoimmune condition, multiple sclerosis (MS) represents the most common demyelinating condition and is, in fact, the most common neurological condition among young- and middle-aged adults. Multiple sclerosis has a significant negative impact on physical, perceptual, and cognitive functioning. Although reduced process...

Traumatic brain injury (TBI) represents a common occurrence that places the brain at risk. This chapter first deals with the various definitional issues related to TBI, where the principal definitional challenges occur with mild injuries, often referred to as concussions. While the majority who sustain a mild TBI recover and may not have any lastin...

This chapter discusses the epidemiological scope of Obstructive Sleep Apnea (OSA) and the characteristics and cause of cognitive impairments in OSA. OSA is a common medical condition and a significant public health concern, with increased rates in males and increased risk associated with obesity and age. Both observational and clinical research stu...

While this chapter focuses on the cognitive consequences of cerebrovascular disease, it is also important to know that cerebrovascular disease is not a unitary condition but rather multiple conditions that affect the cerebrovascular health of the brain. These include obvious conditions such as ischemic and intracerebral hemorrhagic stroke, aneurysm...

Characterized by alterations in mood, both major depression and bipolar disorder are also associated with deficits in neuropsychological function across several cognitive domains, including impaired attention, executive function, language, and processing speed. The majority of findings indicate that these deficits are likely present early in the co...

While this chapter focuses on the cognitive consequences of cerebrovascular disease, it is also important to know that cerebrovascular disease is not a unitary condition but rather multiple conditions that affect the cerebrovascular health of the brain. These include obvious conditions such as ischemic and intracerebral hemorrhagic stroke, aneurysm...

Although generally conceptualized as involving primarily abnormal anxiety regulation, the anxiety disorders as a group along with obsessive–compulsive disorder and post-traumatic stress disorder also appear associated with deficits in cognitive function in several cognitive domains, including attention, executive function, language, memory, and pro...

As humans, we take all of the functions of the brain for granted—this magnificent organ regulates all aspects of cognitive, behavioral, sensory, and motor experiences but seems to run effortlessly. However, given its structural and physiological complexity, there are many ways that something may go wrong. It all begins with conception and a phenome...

This important book describes the effects of a range of medical, psychological, and neurological conditions on brain functioning, specifically cognition. After a brief introduction of brain anatomy and function focusing on neural systems and their complex role in cognition, this book covers common disorders across several medical specialties, as we...

Carbon monoxide (CO) poisoning is one of the most common types of poisoning in the USA and can be either acute or chronic. CO poisoning is diagnosed through examination of the patients’ history and is confirmed by an elevated carboxyhemoglobin level. The symptoms of CO poisoning are often nonspecific including headache, nausea, vomiting, or other f...

In addition to the positive and negative features, deficits in cognition appear to be an important aspect of Schizophrenia and are found in many cognitive domains, including attention, executive function, Schizophrenialanguage, memory, processing speed, and visuospatial ability. The Cognitive impairment associated with schizophrenia are present acr...

Infectious disease is caused by a variety of pathogens including bacteria, viruses, and fungi which are associated with peripheral and neural Inflammation. Recent investigations show that systemic Inflammation can lead to brain injury. This chapter will focus on Sepsis, a systemic illness which causes systemic Inflammation and multi-organ dysfuncti...

Many studies have found some deficits in Cognitive function in anorexia nervosa. While deficits in memory appear to be associated with anorexia nervosa, a more consistent finding is that anorexia nervosa appears to be associated with impairments in a variety of measures of executive function, and it is not clear how the Cognitive impairment that ar...

Each chapter of Brain at risk, the has explored different ways in which the brain is vulnerable for disease and/or various disorders, including ones that are acquired. Some of the latest research is presented in an informative way describing risk and mitigating factors that influence the expression and course of some of the more common major medica...

A number of Pulmonary disease, including chronic obstructive Pulmonary disease (Chronic obstructive pulmonary disease (COPD), Asthma, Acute respiratory distress syndrome (ARDS) (ARDS), not only effect the lungs but have well-described effects on the brain and behavior. Many individuals with Pulmonary disorders experience new and often severe morbid...

Background: White matter integrity in aging populations is associated with increased risk of cognitive decline, dementia diagnosis, and mortality. Population-based data can elucidate this association. Objectives: To examine the association between white matter integrity, as measured by a clinical rating scale of hyperintensities, and mental stat...

Diabetes is a common endocrine disease and a common public health concern. Diabetes is associated with vascular burden and morphological brain change, and the increased risk of cerebrovascular disease appears to mediate much of the association, between diabetes and cognitive deficits. Such cognitive deficits appear to have a greater effect on proce...

Objective: The Trail Making Test - Part B (TMT-B) is a commonly used executive control measure with a known floor effect, limiting the ability to distinguish impairment among individuals unable to complete this task in the standard time limit. Our group previously proposed the TMT-B Efficiency Score (TMT-Be), which captures performance variability...

Introduction: Some studies of Posttraumatic Stress Disorder (PTSD) find executive dysfunction, whereas others do not. We meta-analytically examined the association between executive function and PTSD and used meta-regression to examine the potential moderating effect of PTSD severity on executive function. Methods: We conducted a meta-analysis acco...

Complicated mild traumatic brain injury (mTBI) or cmTBI is based on the presence of visibly identifiable brain pathology on the day-of-injury computed tomography (CT) scan. In a paediatric sample the relation of DOI CT to late MRI findings and neuropsychological outcome was examined. MRI (>12 months) was obtained in paediatric cmTBI patients and a...

The Trail Making Test Part B (TMT-B) is widely used in clinical and research settings as a measure of executive function. Standard administration allows a maximal time score (i.e., floor score) of 300 s. This practice potentially masks performance variability among cognitively impaired individuals who cannot complete the task. For example, performa...

Objective: Magnetic resonance imaging (MRI) provides a method to identify and quantify abnormalities resulting from traumatic brain injury (TBI). MRI abnormalities in children with TBI have not been fully characterized according to the frequency, location, and quantitative measurement of a range of pathologies critical for studies of neuropsycholo...

In 2009 Pertab, James, and Bigler published a critique of two prior meta-analyses by Binder, Rohling, and Larrabee (1997) and Frencham, Fox, and Maybery (2005) that showed small effect size difference at least 3 months post-injury in individuals who had sustained a mild traumatic brain injury (mTBI). The Binder et al. and Frencham et al. meta-analy...

Traumatic brain injury (TBI) is a significant public-health concern. To understand the extent of TBI, it is important to assess the prevalence of TBI in the general population. However, the prevalence of TBI in the general population can be difficult to measure because of differing definitions of TBI, differing TBI severity levels, and underreporti...

Critical illness and its treatment often results in long-term neuropsychiatric morbidities. Consequently, there is a need to focus on means to prevent or ameliorate these morbidities. Animal models provide important data regarding the neurobiological effects of physical activity, including angiogenesis, neurogenesis and release of neurotrophic fact...

Intimate partner violence (IPV) is widespread. Several risk factors are associated with IPV perpetuation, including alcohol use and educational level. The aggression and violence associated with traumatic brain injury (TBI) suggest that brain trauma may also be a risk factor for IPV. To examine the association between TBI and IPV, the authors condu...

Literature suggests that individuals with mild traumatic brain injury (mTBI) show subtle abnormalities in the cognitive control process of performance monitoring. The neural bases of performance monitoring can be measured using the error-related negaitivity (ERN) and post-error positivity (Pe) components of the scalp-recorded event-related potentia...

Studies of traumatic brain injury (TBI) among adult populations demonstrate that such injuries can lead to aggressive behaviors. Related findings suggest that incarcerated individuals have high rates of brain injuries. Such studies suggest that traumatic brain injury may be related to the etiology and recidivism of criminal behavior. Relatively few...

We present behavioral and functional magnetic resonance imaging (fMRI) findings of a 20-year-old female with narcolepsy who completed a standardized fMRI-adapted face memory task both 'off' and 'on' modafinil compared to a normative sample (N = 38). The patient showed poor recognition performance off modafinil (z = -2.03) but intact performance on...

Certain risk factors for cognitive decline appear modifiable. A potentially modifiable marker of inflammation, C-reactive protein may be associated with cognitive deficits, although not all studies have found a relationship between C-reactive protein and cognitive ability. Further, few research papers have examined whether gender may affect any ass...

The basic premise of symptom validity tests (SVTs) is that appropriate effort can be assessed because the designs of SVT measures are thought to be insensitive to all but the most extreme forms of impairment of memory. In patients with mild traumatic brain injury in particular, it is thought that failure on effort measures consistently reflects poo...

Traumatic brain injury can cause numerous behavioral abnormalities including aggression, violence, impulsivity, and apathy, factors that can be associated with criminal behavior and incarceration. To better characterize the association between traumatic brain injury and incarceration, we pooled reported frequencies of lifetime traumatic brain injur...

Recent studies suggest that individuals who have experienced a concussion or mild traumatic brain injury (TBI) show deficits in cognitive control. We tested the hypothesis that behavioral (response time [RT] and error rate) and electrophysiological (N450 and conflict SP components of the event-related potential [ERP]) reflections of conflict monito...

Performance monitoring is a cognitive control process modulated by both cognitive and affective variables. This study examined the relative contributions of negative affect (NA) and cognitive sequelae to performance monitoring dysfunction following severe traumatic brain injury (TBI). We used the error-related negativity (ERN) and post-error positi...

Seven neuropsychology journals that publish on topics relevant to clinical neuropsychology were examined for their experimental rigor according to the standards of the American Academy of Neurology (AAN) in their Clinical Practice Guidelines. By using a keyword approach on topics relevant to forensic neuropsychology, all articles that reported empi...