Neuropsychological functioning of homeless men

An Understated Comorbidity: The Impact of Homelessness on Traumatic Brain Injury

Traumatic brain injury (TBI), a neurovascular injury caused by external force, is a common diagnosis among veterans and those experiencing homelessness (HL). There is a significant overlap in the veteran and homeless population, possibly accounting for the two to seven times greater incidence of TBI among those experiencing HL than the general population. Despite these statistics, individuals experiencing HL are often underdiagnosed and ineffectively treated for TBI. We introduced a novel model of HL. Over 5 weeks, adult Sprague-Dawley rats were randomly assigned to one of the following conditions: TBI only, HL only, TBI + HL, or control (n = 9 per group). To emulate HL, animals (2 animals per cage) were exposed to soiled beddings for 5 weeks. Subsequently, animals were introduced to TBI by using the moderate controlled cortical impact model, then underwent 4 consecutive days of behavioral testing (beam walk (BW), elevated body swing test (EBST), forelimb akinesia (FA), paw grasp (PG), Rotorod, and elevated T-maze). Nissl staining was performed to determine the peri-impact cell survival and the integrity of corpus callosum area. Motor function was significantly impaired by TBI, regardless of housing (beam walk or BW 85.0%, forelimb akinesia or FA 104.7%, and paw grasp or PG 100% greater deficit compared to control). Deficits were worsened by HL in TBI rats (BW 93.3%, FA 40.5%, and PG 50% greater deficit). Two-way ANOVA revealed BW (F(4, 160) = 31.69, p < 0.0001), FA (F(4, 160) = 13.71, p < 0.0001), PG (F(4, 160) = 3.873, p = 0.005), Rotorod (F(4, 160), p = 1.116), and EBST (F(4, 160) = 6.929, p < 0.0001) showed significant differences between groups. The Rotorod and EBST tests showed TBI-induced functional deficits when analyzed by day, but these deficits were not exacerbated by HL. TBI only and TBI + HL rats exhibited typical cortical impact damage (F(3,95) = 51.75, p < 0.0001) and peri-impact cell loss compared to control group (F(3,238) = 47.34, p < 0.0001). Most notably, TBI + HL rats showed significant alterations in WM area measured via the corpus callosum (F(3, 95) = 3.764, p = 0.0133). Worsened behavioral outcomes displayed by TBI + HL rats compared to TBI alone suggest HL contributes to TBI functional deficits. While an intact white matter, such as the corpus callosum, may lessen the consequent functional deficits associated with TBI by enhancing hemispheric communications, there are likely alternative cellular and molecular pathways mitigating TBI-associated inflammatory or oxidative stress responses. Here, we showed that the environmental condition of the patient, i.e., HL, participates in white matter integrity and behavioral outcomes, suggesting its key role in the disease diagnosis to aptly treat TBI patients.

Memory, fluid reasoning, and functional capacity in adults experiencing homelessness

BACKGROUND AND OBJECTIVE

In individuals experiencing homelessness, determinants of functional capacity (i.e. the ability to perform activities of daily living) are poorly understood. Identifying potentially modifiable correlates of functional capacity, such as cognitive abilities, may inform treatment targets to address independence and housing stability. This study aimed to identify the strongest neuropsychological predictors of variance in functional performance in 100 adults living in a homeless shelter.

METHODS

Participants completed a brief cognitive screening test, from which four composite scores were derived, as well as tests of processing speed, fluid reasoning, premorbid intellectual function, and performance-based functional capacity. We conducted a hierarchical linear regression to predict variance in functional capacity.

RESULTS

Beyond the impact of education and premorbid intellectual function, better memory and fluid reasoning predicted better functional performance.

CONCLUSIONS

Although our cross-sectional design does not permit causal inference, it is possible that interventions targeting memory and fluid reasoning may improve functional ability in individuals experiencing homelessness.

The Misguided Veneration of Averageness in Clinical Neuroscience: A Call to Value Diversity over Typicality

Research and practice in clinical neurosciences often involve cognitive assessment. However, this has traditionally used a nomothetic approach, comparing the performance of patients to normative samples. This method of defining abnormality places the average test performance of neurologically healthy individuals at its center. However, evidence suggests that neurological 'abnormalities' are very common, as is the diversity of cognitive abilities. The veneration of central tendency in cognitive assessment, i.e., equating typicality with healthy or ideal, is, I argue, misguided on neurodiversity, bio-evolutionary, and cognitive neuroscientific grounds. Furthermore, the use of average performance as an anchor point for normal performance is unreliable in practice and frequently leads to the mischaracterization of cognitive impairments. Examples are explored of how individuals who are already vulnerable for socioeconomic reasons can easily be over-pathologized. At a practical level, by valuing diversity rather than typicality, cognitive assessments can become more idiographic and focused on change at the level of the individual. The use of existing methods that approach cognitive assessment ideographically is briefly discussed, including premorbid estimation methods and informant reports. Moving the focus away from averageness to valuing diversity for both clinical cognitive assessments and inclusion of diverse groups in research is, I argue, a more just and effective way forward for clinical neurosciences.

Pain in People Experiencing Homelessness: A Scoping Review

BACKGROUND

Prior work suggests that people experiencing homelessness (PEH) are at heightened risk for developing pain and have a uniquely burdensome pain experience.

PURPOSE

The aim of this scoping review was to map the current peer-reviewed, published literature on the pain experience of PEH.

METHODS

In accordance with the US Annual Homeless Assessment Report, we defined homelessness as lacking shelter or a fixed address within the last year. We conceptualized the pain experience via a modified version of the Social Communication Model of Pain, which considers patient, provider, and contextual factors. Published articles were identified with CINHAL, Embase, PubMed, PsycINFO, and Web of Science databases.

RESULTS

Sixty-nine studies met inclusion criteria. Studies revealed that PEH have high rates of pain and experience high levels of pain intensity and interference. Substantially fewer studies examined other factors relevant to the pain experience, such as self-management, treatment-seeking behaviors, and pain management within healthcare settings. Nonetheless, initial evidence suggests that pain is undermanaged in PEH.

CONCLUSIONS

Future research directions to understand pain and homelessness are discussed, including factors contributing to the under-management of pain. This scoping review may inform future work to develop interventions to address the specific pain care needs of PEH.

A Network Analysis of the Relationship Between Mental and Physical Health in Unsheltered Homeless Persons in Los Angeles County

Homelessness is a public health crisis both nationally, in the United States, and internationally. Nevertheless, due to the hidden vulnerabilities of persons who are without shelter, little is known about their experiences during periods of homelessness. The present research adopts a network approach that conceptualizes how the major risk factors of homelessness interact, namely substance abuse problems, poor mental health, disability, and exposure to physical or sexual violence by an intimate partner. Our analysis draws on a large demographic survey of over 5,000 unsheltered homeless persons conducted in 2017 by the Los Angeles Homeless Services Authority. We estimated a network structure for 12 survey items tapping individual risk using the graphical least absolute shrinkage and selection operator algorithm. We then examined network centrality metrics and implemented a community detection algorithm to detect communities in the network. Our results indicated that mental illness and intimate partner violence (IPV) are central measures that connect all other mental and physical health variables together and that post-traumatic stress disorder and IPV are both highly affected by changes in any part of the network and, in turn, affect changes in other parts of the network. A community detection analysis derived four communities characterized by disability, sexual victimization and health, substance use, and mental health issues. Finally, a directed acyclic graph revealed that drug abuse and physical disability were key drivers of the overall system. We conclude with a discussion of the major implications of our findings and suggest how our results might inform programs aimed at homelessness prevention and intervention.

Neuropsychological functioning of homeless people in Paris: An exploratory study

Homelessness is a multifactorial issue, influenced by structural and individual factors. These factors include health status, which has been reported to be poorer among people experiencing homelessness. Although the somatic and mental health of homeless individuals has already been studied in France, to our knowledge, no research has been conducted on neuropsychological functioning in this country. Studies out with France have identified cognitive impairments as highly prevalent among homeless people, and these impairments are likely affected by local structural factors, such as healthcare access. Therefore, we conducted an exploratory study in Paris to evaluate cognition and associated factors in homeless adults. The second objective was to identify methodological specificities to consider in a future larger-scale study and for the application of the outcomes. For this exploratory phase, 14 individuals were recruited from specific services and were interviewed regarding their social, neurological, and psychiatric history, before completing a set of cognitive tests. The results showed a high diversity of profiles in terms of demographic characteristics, including being a migrant and/or illiterate. A high proportion of participants had signs of traumatic brain injury, anxiety, depressive disorders, and post-traumatic stress disorders. Most cognitive scores were in the low average of normative data. No statistical association was found between identified risk factors and cognitive performance. Future studies should consider the sociodemographic specificities of the homeless population and design appropriate measurement tools to improve the understanding of neuropsychological profiles.

Exploring and Mapping Screening Tools for Cognitive Impairment and Traumatic Brain Injury in the Homelessness Context: A Scoping Review

Cognitive impairment is common amongst people experiencing homelessness, yet cognitive screening and the collection of history of brain injury rarely features in homelessness service delivery practice. The purpose of this research was to scope and map strategies for screening for the potential presence of cognitive impairment or brain injury amongst people experiencing homelessness and identify instruments that could be administered by homelessness service staff to facilitate referral for formal diagnosis and appropriate support. A search was conducted across five databases, followed by a hand search from relevant systematic reviews. A total of 108 publications were included for analysis. Described in the literature were 151 instruments for measuring cognitive function and 8 instruments screening for history of brain injury. Tools that were described in more than two publications, screening for the potential presence of cognitive impairment or history of brain injury, were included for analysis. Of those regularly described, only three instruments measuring cognitive function and three measuring history of brain injury (all of which focused on traumatic brain injury (TBI)) may be administered by non-specialist assessors. The Trail Making Test (TMT) and the Ohio State University Traumatic Brain Injury Identification Method (OSU TBI-ID) are both potentially viable tools for supporting the identification of a likely cognitive impairment or TBI history in the homelessness service context. Further population-specific research and implementation science research is required to maximise the potential for practice application success.

Neurocognitive health of older adults experiencing homelessness in Oakland, California

Background and objectives

The homeless population in the US is aging. Cognitive impairment is prevalent in this population, yet little is known about the neurologic etiologies of such impairment. Addressing this gap in knowledge is important because homeless older adults with cognitive impairment due to neurodegenerative disease may need lifelong tailored support to obtain and maintain housing. In this study, we characterized the neurocognitive health of a sample of adults who experienced homelessness for the first time after age 50 using gold standard behavioral neurology examination practices.

Methods

We conducted a descriptive cross-sectional study of older adults who first experienced homelessness after age 50. We recruited our sample purposively from an ongoing longitudinal cohort study of adults who were aged 50 and over and homeless when they entered the cohort. For this sub study, we enrolled a convenience sample from those who reported their first episode of homelessness after age 50. We did not exclude individuals based on history of substance use. Neurologists conducted a structured neurocognitive history intake, neurological examination, neuropsychological evaluation, and functional assessment between November 2020 and February 2021. We screened all participants for neurocognitive disorders using gold standard clinical research diagnostic criteria.

Results

We evaluated 25 participants, most were men (76%) and Black (84%), with a median age of 61 years. The most common neurocognitive complaints included deficits in recent episodic memory (n = 15, 60%), executive functions (n = 13, 52%), and behavior/mood, with apathy being the most common complaint (n = 20, 80%). Neuropsychological testing revealed a high prevalence of socioemotional deficits (n = 20, 80%). Common neurological examination deficits included difficulties with coordination, such as impaired Luria task (n = 16, 64%), signs of distal peripheral neuropathy (n = 8, 32%), anosmia/hyposmia (n = 4, 21%), and signs of mild Parkinsonism (n = 5, 20%). The most common diagnoses were MCI (n = 7, 28%), bvFTD (n = 4, 16%), AD (n = 4, 16%), and DLB (n = 2, 8%).

Discussion

Our findings suggest that neurocognitive concerns and examination deficits are common among older homeless adults. Specific neurocognitive disorders may be overrepresented in this population, particularly frontotemporal disorders. Longitudinal studies involving brain biomarkers are needed to characterize the neurocognitive health of this vulnerable population more precisely.

Health Determinants among North Americans Experiencing Homelessness and Traumatic Brain Injury: A Scoping Review

Traumatic brain injury (TBI) in those experiencing homelessness has been described in recent literature as a contributor to increased morbidity, decreased functional independence, and early mortality. In this systematically conducted scoping review, we aimed to better delineate the health determinants—as defined by Health Canada/Centers for Disease Control and Prevention (CDC)—associated with TBI in North Americans experiencing homelessness. BIOSIS, MEDLINE, CINAHL, EMBASE, SCOPUS, and Global Health were searched from inception to December 30, 2020. Gray literature search consisted of relevant meeting proceedings. A two-step process was undertaken, assessing title/abstract and full articles, respectively, based on inclusion/exclusion criteria, leading to the final 20 articles included in the review. Data were abstracted, assessing the aims, literature quality, and bias. Five health determinants displayed strong associations with TBI in those North Americans experiencing homelessness, including male gender, poor physical environment, negative personal health behaviors, adverse childhood experiences (ACEs), and low educational attainment. In those studies displaying a comparator population experiencing homelessness without TBI, the TBI group displayed trends toward increased disparity in Health Canada and CDC defined health determinants. Most studies suffered from moderate limitations. There are associations between male gender, poor physical environment, negative personal health behaviors, ACEs, and limited education in those experiencing homelessness and TBI. The results suggest that those experiencing homelessness with TBI in North America suffer poorer health consequences than those without TBI. Future research on TBI in North Americans experiencing homelessness should focus on health determinants as potential areas for intervention, which may lead to improved outcomes for those experiencing both homelessness and TBI.

Homelessness and Research: Methodological Obstacles and Lessons Learned from a Psychological Study in Parisian Homeless Services

Homelessness, defined as a lack of appropriate, stable, and permanent housing, is a common issue in many societies and is linked to both structural and individual factors. These factors include psychological mechanisms and disorders which can trigger or worsen already precarious situations. In order for these factors to be taken into account in social rehabilitation programs, they need to be precisely described. However, at present, studies in this field are lacking in France. Despite homelessness being an issue across the country, few studies have evaluated the underlying psychological or neuropsychological mechanisms. More data are needed, not only to provide an accurate description of the situation in France, but also to ensure that foreign observations and interventions are relevant for application to the homeless population. In order to achieve this, more quantitative and qualitative data and investigative methodologies and studies are needed. Sharing experience and methods within the scientific community is one way to support further research, particularly in complex domains such as homelessness. At the moment, only a few such papers have been published. In this paper, we share our experiences from a research project that started in 2020 (currently unpublished) on the prevalence of cognitive disorders among homeless service users in Paris. We describe the exploratory phase of our project, obstacles encountered during the implementation of the study, including how we dealt with ethical issues, and data collection. We end the paper with recommendations for future psychological studies on homelessness.

Cognitive Dysfunction, Brain Volumes, and Traumatic Brain Injury in Homeless Persons

Although homeless persons experience traumatic brain injury (TBI) frequently, little is known about the structural and functional brain changes in this group. We aimed to describe brain volume changes and related cognitive/motor deficits in homeless persons with or without TBI versus controls. Participants underwent T1-weighted magnetic resonance imaging (MRI), neuropsychological (NP) tests (the Grooved Pegboard Test [GPT]/Finger Tapping Test [FTT]), alcohol/drug use screens (the Alcohol Use Disorders Identification Test [AUDIT]/Drug Abuse Screening Test [DAST]), and questionnaires (the Brain Injury Screening Questionnaire [BISQ]/General Information Questionnaire [GIQ]) to determine TBI. Normalized volumes of brain substructures from MRI were derived from FreeSurfer. Comparisons were tested by Mann-Whitney U and Kruskal-Wallis rank sum tests. Leave-one-out cross-validation using random forest classifier was applied to determine the ability of predicting TBI. Diagnostic ability of this classifier was assessed using area under the receiver operating characteristic curve (AUC). Fifty-one participants—25 homeless persons (9 with TBI) and 26 controls—were included. The homeless group had higher AUDIT scores and smaller thalamus and brainstem volumes (p < 0.001) than controls. Within homeless participants, the TBI group had reduced normalized volumes of nucleus accumbens, thalamus, ventral diencephalon, and brainstem compared with the non-TBI group (p < 0.001). Homeless participants took more time on the GPT compared with controls using both hands (p < 0.0001); but the observed effects were more pronounced in the homeless group with TBI in the non-dominant hand. Homeless persons with TBI had fewer dominant hand finger taps than controls (p = 0.0096), and homeless participants with (p = 0.0148) or without TBI (p = 0.0093) tapped less than controls with their non-dominant hand. In all participants, TBI was predicted with an AUC of 0.95 (95% confidence interval [CI]: 0.89-1.00) by the classifier modeled on MRI, NP tests, and screening data combined. The MRI-data-based classifier was the best predictor of TBI within the homeless group (AUC: 0.76, 95% CI: 0.53-0.99). Normalized volumes of specific brain substructures were important indicators of TBI in homeless participants and they are important indicators of TBI in the state of homelessness itself. They may improve predictive ability of NP and screening tests in determining these outcomes.

The speech, language and communication needs of rough sleepers in London

BACKGROUND

There is very little awareness of the speech, language and communication needs (SLCN) of rough sleepers. The small amount of documentation that does exist involves a wider group of homeless adults (not just rough sleepers), and reports that communication needs are an area of concern.

AIMS

To investigate: (1) the reported prevalence of SLCN amongst UK nationals recorded on the Combined Homeless and Information Network (CHAIN) as sleeping on the streets of London; (2) whether rough sleepers with reported SLCN differ from those without; and (3) what factors best predict patterns of rough sleeping and accommodation stays.

METHODS & PROCEDURES

A data set of 513 participants was provided by CHAIN, which contained information relating to all new rough sleepers and people with long-term histories of rough sleeping (UK nationals only) recorded by street outreach teams in London between 1 April and 30 June 2013. Also included was data about UK nationals provided with support by the Homelessness and Brain Injury Project. The data set contained information including basic demographics, communication skills, health and social care needs, and institutional background and extended to a 5-year period.

OUTCOMES & RESULTS

(1) SLCN data were often not recorded with data available for only 62% of individuals on the CHAIN databases. However, for those with SLCN data, the prevalence of SLCN was significantly higher than for the general population (17.1%; p < 0.001). (2) There were no significant differences between those with and without SLCN on additional risk factors, quarters rough sleeping, accommodation stays or staff-recorded alerts. (3) There was a positive correlation between rough sleeping and additional risk factors for those with SLCN (r = 0.32, p < 0.001) and for those without (r = 0.25, p < 0.001). Regression analysis indicated that additional risk factors were more predictive than SLCN in explaining the number of quarters rough sleeping and accommodation stays.

CONCLUSIONS & IMPLICATIONS

SLCN are highly prevalent amongst rough sleepers and significantly greater than for the UK general population. SLCN are not clearly related to rough sleeping behaviour, but the presence of additional risk factors is highly significant in this regard. Homelessness organizations should provide training for staff in SLCN in order to promote better recording of SLCN, inclusive communication and appropriate support to people who are homeless. Further research is also needed to understand better the communication needs of rough sleepers. What this study adds What is already known on the subject There is very little literature concerning the SLCN of rough sleepers, but that which exists suggests that communication needs are an area of concern. There is relatively little awareness of SLCN in practice in this field. What this paper adds to existing knowledge This study is the first to provide information on SLCN recording in this population. It reports large-scale prevalence data on SLCN in rough sleepers, showing a significantly higher risk in this group. Unexpectedly, SLCN did not clearly relate to patterns of rough sleeping and accommodation, but this may be due to the relatively crude data available in routine practice. What are the potential or actual clinical implications of this work? Wider awareness and training on SLCN in the homelessness sector is needed coupled with more systematic and objective assessment of communication in rough sleepers.

Language ability and adult homelessness

BACKGROUND

People experiencing homelessness are at increased risk of neurological disorder due to multiple factors such as substance abuse, infection, and higher rates of serious mental illness and traumatic brain injury. This could affect cognitive and language skills. Indeed, past research has suggested that certain language-related skills tend to be lower in people experiencing homelessness. However, that research has compared homeless samples with age-matched normative samples and not with samples of people from similar socio-economic backgrounds. Therefore, it is unclear whether homelessness is even a relevant factor, or if adults who are homeless tend to have appropriate linguistic skills relative to their social and educational background.

AIMS

To compare the language skills of a group of adults with histories of homelessness with an education-matched control group. It was hypothesized that participants with histories of homelessness would have worse language performance than their matched controls.

METHODS & PROCEDURES

A quasi-experimental design was employed involving 17 adults with histories of homelessness, mainly rough sleeping, in the city of Quito in Ecuador, and a sample of 16 adults who had never been homeless. All were assessed with measures of head injury, substance dependence, affective disorder and language skills. A paired-sample analysis was performed on homeless and control participants matched for educational background, used as an index of socio-economic background.

OUTCOMES & RESULTS

The mean years of formal education was low in both the homeless sample (mean = 5.82 years) and the control sample (mean = 6.75 years). There were no differences between the groups for any demographic or clinical factors, nor for a measure of expected or 'premorbid' ability based on single-word reading, nor for current non-verbal cognitive functioning. In contrast, the homeless group scored significantly worse than the control group on measures of auditory comprehension and oral expression.

CONCLUSIONS & IMPLICATIONS

Adults with histories of homelessness may have worse language skills than would be expected based on their educational backgrounds and non-verbal cognitive abilities. It is possible that some of this lower language ability is pathological, in the form of either a developmental language disorder or an acquired impairment. As such, some adults who are homeless may benefit from therapy directed at clinical language disorders.

Traumatic brain injury in homeless and marginally housed individuals: a systematic review and meta-analysis

BACKGROUND

Homelessness is a global public health concern, and traumatic brain injury (TBI) could represent an underappreciated factor in the health trajectories of homeless and marginally housed individuals. We aimed to evaluate the lifetime prevalence of TBI in this population, and to summarise findings on TBI incidence and the association between TBI and health-related or functioning-related outcomes.

METHODS

For this systematic review and meta-analysis, we searched without date restrictions for original research studies in English that reported data on the prevalence or incidence of TBI, or the association between TBI and one or more health-related or function-related outcome measures. Studies were included if they had a group or clearly identifiable subgroup of individuals who were homeless, marginally housed, or seeking services for homeless people. With use of random-effects models, we calculated pooled estimates of the lifetime prevalence of any severity of TBI and the lifetime prevalence of moderate or severe TBI. We used meta-regression and subgroup analysis to evaluate potential moderators of prevalence estimates and the leave-one-out method for sensitivity analyses. We then summarised findings from all studies that evaluated TBI incidence and the association between TBI and health-related or functioning-related outcomes. All statistical analyses were done using R version 3.5.1. The study is registered with PROSPERO, number CRD42019119678.

FINDINGS

Of 463 potentially eligible studies identified by the search, 38 studies were included in the systematic review and 22 studies were included in the meta-analysis. The lifetime prevalence of any severity of TBI in homeless and marginally housed individuals (18 studies, n=9702 individuals) was 53·1% (95% CI 46·4-59·7; I²=97%) and the lifetime prevalence of moderate or severe TBI (nine studies, n=5787) was 22·5% (13·5-35·0; I²=99%). The method used to ascertain TBI history, the age of the sample, and the sample size significantly moderated estimated lifetime prevalence of any severity of TBI. TBI was consistently associated with poorer self-reported physical and mental health, higher suicidality and suicide risk, memory concerns, and increased health service use and criminal justice system involvement.

INTERPRETATION

The lifetime prevalence of TBI is high among homeless and marginally housed individuals, and a history of TBI is associated with poorer health and general functioning. Health-care providers and public health officials should have an increased awareness of the burden of TBI in this population. Prospective and longitudinal studies are needed to better understand how the health of this population is affected by TBI.

FUNDING

Canadian Institutes of Health Research.

Housing Stability and Neurocognitive Functioning in Homeless Adults With Mental Illness: A Subgroup Analysis of the At Home/Chez Soi Study

Objective: This study examined the association of housing stability with neurocognitive outcomes of a well-characterized sample of homeless adults with mental illness over 18 months and sought to identify demographic and clinical variables associated with changes in neurocognitive functioning. Method: A total of 902 participants in the At Home/Chez Soi study completed neuropsychological measures 6 and 24 months after study enrollment to assess neurocognitive functioning, specifically verbal learning and memory, cognitive flexibility, and complex processing speed. Multivariable linear regression was performed to assess the association of housing stability with changes in neurocognitive functioning between 6 and 24 months and to examine the effect of demographic and clinical variables on changes in neurocognitive functioning. Results: Overall neurocognitive impairment remained high over the study period (70% at 6 months and 67% at 24 months) with a small but significant improvement in the proportion of those experiencing more severe impairment (54% vs. 49% p < 0.002). Housing stability was not associated with any of the neuropsychological measures or domains examined; improvement in neurocognitive functioning was associated with younger age, and bipolar affective disorder at baseline. Conclusions: The high prevalence and persistence of overall neurocognitive impairment in our sample suggests targeted approaches to improve neurocognitive functioning merit consideration as part of health interventions to improve everyday functioning and outcomes for this population. Further efforts are needed to identify potential modifiable factors that contribute to improvement in cognitive functioning in homeless adults with mental illness.

[One homeless person out of ten suffers from cognitive disorders: What do we know about these impairments? A systematic review of homeless people's cognition]

OBJECTIVES

Homelessness is associated with several issues (psychiatric and neurological disorders, neurodevelopmental difficulties, malnutrition…) which are also risk factors for cognitive disorders. However, little is known about the relationship between the cognition of homeless people and these eventual explicative etiologies. The aim of this work is to complete the results of Depp et al. about cognition in homelessness by proposing a systematic review of the neuropsychological disorders of homeless people associated with an analysis of the etiologies likely to explain these disorders.

METHODS

We followed the PRISMA recommendations to build up this work. We analyzed the abstracts of 385 papers found on databases PSYCINFO and PubMed. Twenty-two studies have been selected for respecting our criteria (at least one valid neuropsychological test ; general group of homeless people and not a sub-group of this population ; study published in English). The prevalence quality has been evaluated through the criteria of Loney et al. Cognitive scores and etiological factors have been compared between studies.

RESULTS

The 22 studies represent only nine countries. More than half of them are considered as having a poor prevalence quality. In total, 4,256 participants have been evaluated. Their mean age was around 40 years, and 85 % of the participants were men. The results show a prevalence of cognitive disorders (MMSE) in 8.77 % of the sample. The mean IQ was 87.47 and the premorbid IQ 94.59. We also notice possible disorders affecting the episodic memory and the executive functions. Mean scores for short-term memory, speech and visuo-spatial functions are relatively low. None of the studies evaluated the praxia, the gnosia or the social cognition. The heterogeneity of studies and the lack of data did not allow us to give general conclusions about the etiology of these disorders. However, we see that around 40 % of the time subjects had histories of brain injuries and 89 % of childhood trauma. Intellectual disability is found in 49 % of the sample of a single study. Also, 70 % of the homeless population have been diagnosed with substance-related disorders and 65 % with psychiatric disorders. It appears that the only factors correlated with cognitive disorders would be the history of brain injuries and childhood traumas.

CONCLUSIONS

We confirm that homeless people often suffer from cognitive difficulties, and some of these difficulties (memory, executive functioning) are severe. Yet the etiology of these disorders remain relatively unknown: even if we observe a high prevalence of psychiatric, substance-related, neurodevelopmental and neurological issues by the homeless population, only a few of them (brain injury history and childhood trauma) seem to be correlated with cognition in homelessness. The potential explicative factors have been too rarely explored to bring a powerful explanation of cognitive disorders in homeless people. Further research needs to be done in order to give a more precise neuropsychological profile of the homeless population and to better understand what the disorders are rooted in. Last but not least, all this research and knowledge should be applied more to the care of homeless people by providing neuropsychological assessment and rehabilitation and by training the team to detect cognitive disorders and to support the person with a cognitive disability.

Health assessments and screening tools for adults experiencing homelessness: a systematic review

BACKGROUND

Homelessness is increasing globally. It results in poorer physical and mental health than age matched people living in permanent housing. Better information on the health needs of people experiencing homelessness is needed to inform effective resourcing, planning and service delivery by government and care organisations. The aim of this review was to identify assessment tools that are valid, reliable and appropriate to measure the health status of people who are homeless.

METHODS

Data sources: A systematic literature search was conducted in PubMed (and Medline), PsychInfo, Scopus, CINAHL and ERIC from database inception until September 2018. Key words used were homeless, homelessness, homeless persons, vagrancy, health status, health, health issues, health assessment and health screening. The protocol was registered with PROSPERO. The National Health and Medical Research Council of Australia (NHMRC) hierarchy of evidence was applied; methodological quality of included articles was assessed using the McMaster critical appraisal tools and psychometric properties of the tools were appraised using the International Centre for Allied Health Evidence Ready Reckoner.

RESULTS

Diverse tools and measures (N = 71) were administered within, and across the reviewed studies (N = 37), with the main focus being on general health, oral health and nutrition. Eleven assessment tools in 13 studies had evidence of appropriate psychometric testing for the target population in domains of quality of life and health status, injury, substance use, mental health, psychological and cognitive function. Methodological quality of articles and tools were assessed as moderate to good. No validated tools were identified to assess oral health, chronic conditions, anthropometry, demography, nutrition, continence, functional decline and frailty, or vision and hearing. However, assessments of physical constructs (such as oral health, anthropometry, vision and hearing) could be applied to homeless people on a presumption of validity, because the constructs would be measured with clinical indicators in the same manner as people living in permanent dwellings.

CONCLUSIONS

This review highlighted the need to develop consistent and comprehensive health assessment tools validated with, and tailored for, adults experiencing homelessness.

Factors associated with cognitive impairment in a cohort of older homeless adults: Results from the HOPE HOME study

BACKGROUND

We evaluated cognitive function and factors associated with cognitive impairment in a cohort of older homeless adults. We hypothesized that substance use and a history of traumatic brain injury would be associated with cognitive impairment.

METHODS

We recruited 350 homeless individuals aged ≥50 years using population-based sampling and conducted structured interviews and neuropsychological testing. We evaluated alcohol use with the Alcohol Use Disorder Identification Test, defining high-severity alcohol use as a total score ≥16 or ≥4 on the alcohol dependency sub-scale. We assessed global cognition with the Modified Mini-Mental State Test (3MS) and processing speed and executive function with the Trail Making Test (TMTB), defining impairment as performing 1.5 standard deviations below the standardized mean. We used multivariable logistic regression to examine the association between alcohol use and cognition.

RESULTS

Participants had a median age of 58 years [IQR 54-61], 76.7% were men, and 79.9% were African American. A quarter (25.1%) of participants met criteria for impairment on the 3MS; 32.9% met criteria for impairment on TMTB. In models adjusted for sociodemographic variables and health conditions, high-severity alcohol use was associated with global cognitive impairment (AOR 2.39, CI 1.19-4.79) and executive dysfunction (AOR 3.09, CI 1.61-5.92).

CONCLUSIONS

Older homeless adults displayed a prevalence of cognitive impairment 3-4 times higher than has been observed in general population adults aged 70 and older. Impaired cognition in older homeless adults could impact access to housing programs and the treatment of health conditions, including the treatment of alcohol use disorders.

Neurocognitive impairment in a large sample of homeless adults with mental illness

OBJECTIVE

This study examines neurocognitive functioning in a large, well-characterized sample of homeless adults with mental illness and assesses demographic and clinical factors associated with neurocognitive performance.

METHOD

A total of 1500 homeless adults with mental illness enrolled in the At Home Chez Soi study completed neuropsychological measures assessing speed of information processing, memory, and executive functioning. Sociodemographic and clinical data were also collected. Linear regression analyses were conducted to examine factors associated with neurocognitive performance.

RESULTS

Approximately half of our sample met criteria for psychosis, major depressive disorder, and alcohol or substance use disorder, and nearly half had experienced severe traumatic brain injury. Overall, 72% of participants demonstrated cognitive impairment, including deficits in processing speed (48%), verbal learning (71%) and recall (67%), and executive functioning (38%). The overall statistical model explained 19.8% of the variance in the neurocognitive summary score, with reduced neurocognitive performance associated with older age, lower education, first language other than English or French, Black or Other ethnicity, and the presence of psychosis.

CONCLUSION

Homeless adults with mental illness experience impairment in multiple neuropsychological domains. Much of the variance in our sample's cognitive performance remains unexplained, highlighting the need for further research in the mechanisms underlying cognitive impairment in this population.

A quantitative review of cognitive functioning in homeless adults

Homeless people experience elevated rates of risk factors for cognitive impairment. We reviewed available peer-reviewed studies reporting data from objective measures of cognition in samples identified as homeless. Pooled sample-weighted estimates of global cognitive screening measures, full-scale intelligence quotient (IQ), and premorbid IQ were calculated, in addition to pooled sample characteristics, to understand the representativeness of available studies. A total of 24 unique studies were identified, with 2969 subjects. The pooled estimate for the frequency of cognitive impairment was 25%, and the mean full-scale IQ score was 85, 1 standard deviation below the mean of the normal population. Cognitive impairment was found to be common among homeless adults and may be a transdiagnostic problem that impedes rehabilitative efforts in this population. Comparatively little data are available about cognition in homeless women and unsheltered persons.

Head injury and mortality in the homeless

Risk factors for head injury are also risk factors for becoming homeless but there is little research on this vulnerable group, who can be neglected by health services that specialize in acquired brain injury. This study investigates the prevalence of admissions to hospital with a head injury in the homeless and associations with later mortality. It compares homeless people with and without a record of hospitalized head injury (HHI) and the Glasgow population. Data were obtained from a U.K. National Health Service strategy to enhance care of the homeless. This included development and production of local registers of homeless people. In Glasgow, the initiative took place over a seven-year period (2004-2010) and comprised 40 general practitioner (family practice) services in the locality of 55 homeless hostels. The register was linked to hospital admissions with head injury recorded in Scottish Medical Records and to the General Register of Scotland, which records deaths. A total of 1590 homeless people was registered in general practitioner (family doctor) returns. The prevalence of admission to hospital with head injury in the homeless over a 30-year period (13.5%) was 5.4 times higher than in the Glasgow population. In the homeless with HHI, 33.6% died in the seven-year census period, compared with 13.9% in the homeless with no hospitalized HI (NHHI). The standardized mortality ratio for HHI (4.51) was more than twice that for NHHI (2.08). The standardized mortality ratio for HHI aged 15-34 (17.54) was particularly high. These findings suggest that HHI is common in the homeless relative to the general population and is a risk factor for late mortality in the homeless population.

Cognitive deficit and mental health in homeless transition-age youth

BACKGROUND AND OBJECTIVES

There is increasing recognition of the cognitive consequences of socioeconomic adversity during childhood, which can impair learning and negatively affect social and emotional development. However, there is a paucity of research on cognitive functioning and mental health among transition-age homeless youth. This study aimed to address this knowledge gap by examining the prevalence and functional significance of cognitive impairment and mental health disorders in a sample of 18- to 22-year-old homeless youth.

METHODS

Participants (N = 73) were recruited from a vocational support program at Covenant House New York, a care agency for homeless youth. Assessments included diagnostic assessment for mental health disorders and evaluation of neurocognition and vocational outcomes.

RESULTS

Youth demonstrated histories of academic instability, academic achievement below expectation, and high rates of untreated psychiatric disorders, the most prominent of which were anxiety, substance use, and mood disorders. Of those who had a mental health diagnosis, more than half demonstrated cognitive deficits. Performance on measures of working memory and verbal memory was <70% of that of the age-matched normative population. Cognitive impairment was associated with a significant risk for making a wage insufficient for independent living.

CONCLUSIONS

These data confirm the need to focus on cognitive as well as emotional and physical health in transition-age youth. Comprehensive intervention at this later developmental stage has the potential to facilitate the acquisition of skills needed for academic, vocational, and independent living success in adulthood.

Memory impairment among people who are homeless: a systematic review

Cognitive impairment may interfere with an individual's ability to function independently in the community and may increase the risk of becoming and remaining homeless. The purpose of this study was to systematically review the literature on memory deficits among people who are homeless in order to gain a better understanding of its nature, causes and prevalence. Studies that measured memory functioning as an outcome among a sample of homeless persons were included. Data on sampling, outcome measures, facet of memory explored and prevalence of memory impairment were extracted from all selected research studies. Included studies were evaluated using a critical appraisal process targetted for reviewing prevalence studies. Eleven studies were included in the review. Verbal memory was the most commonly studied facet of memory. Potential contributing factors to memory deficits among persons who are homeless were explored in seven studies. Memory deficits were common among the samples of homeless persons studied. However, there was a great deal of variation in the methodology and quality of the included studies. Conceptualisations of "homelessness" also differed across studies. There is a need for more controlled research using validated neuropsychological tools to evaluate memory impairment among people who are homeless.

Personality disorders and treatment drop out in the homeless

The homeless drop out of treatment relatively frequently. Also, prevalence rates of personality disorders are much higher in the homeless group than in the general population. We hypothesize that when both variables coexist - homelessness and personality disorders - the possibility of treatment drop out grows. The aim of this study was to analyze the hypotheses, that is, to study how the existence of personality disorders affects the evolution of and permanence in treatment. One sample of homeless people in a therapeutic community (N = 89) was studied. The structured clinical interview for the diagnostic and statistical manual of mental disorders (DSM-IV-TR) was administered and participants were asked to complete the Millon Clinical Multiaxial Inventory-II (MCMI-II). Cluster B personality disorders (antisocial, borderline, and narcissistic) avoided permanence in the treatment process while cluster C disorders, as dependent, favored adhesion to the treatment and improved the prognosis. Knowledge of these personality characteristics should be used to advocate for better services to support homeless people and prevent their dropping out before completing treatment.

Traumatic brain injury among people who are homeless: a systematic review

Background

Homelessness and poverty are important social problems, and reducing the prevalence of homelessness and the incidence of injury and illness among people who are homeless would have significant financial, societal, and individual implications. Recent research has identified high rates of traumatic brain injury (TBI) among this population, but to date there has not been a review of the literature on this topic. The objective of this systematic review was to review the current state of the literature on TBI and homelessness in order to identify knowledge gaps and direct future research.

Methods

A systematic literature search was conducted in PsycINFO (1887–2012), Embase (1947–2012), and MEDLINE/Pubmed (1966–2012) to identify all published research studies on TBI and homelessness. Data on setting, sampling, outcome measures, and rate of TBI were extracted from these studies.

Results

Eight research studies were identified. The rate of TBI among samples of persons who were homeless varied across studies, ranging from 8%-53%. Across the studies there was generally little information to adequately describe the research setting, sample sizes were small and consisted mainly of adult males, demographic information was not well described, and validated screening tools were rarely used. The methodological quality of the studies included was generally moderate and there was little information to illustrate that the studies were adequately powered or that study samples were representative of the source population. There was also an absence of qualitative studies in the literature.

Conclusions

The rate of TBI is higher among persons who are homeless as compared to the general population. Both descriptive and interventional studies of individuals who are homeless should include a psychometrically sound measure of history of TBI and related disability. Education of caregivers of persons who are at risk of becoming, or are homeless, should involve training on TBI. Dissemination of knowledge to key stakeholders such as people who are homeless, their families, and public policy makers is also advocated.

Neurobehavioural and cognitive function is linked to childhood trauma in homeless adults

OBJECTIVES

To describe levels of traumatic childhood events in a sample of homeless individuals and to assess the contribution of traumatic events to neurobehavioural traits (measured with the Frontal Systems Behaviour Scale, FrSBe) and general cognitive function (IQ).

DESIGN

A sample of 55 homeless adults was recruited from homeless services in the city of Sheffield, UK. All were interviewed to acquire substance misuse information, record experiences of childhood trauma, and assess cognitive and neurobehavioural traits.

METHODS

Experiences of abuse and neglect were assessed with the Childhood Trauma Questionnaire. Participants also completed the Wechsler Abbreviated Scale of Intelligence and the FrSBe, which was completed with respect to current behaviour and conduct prior to homelessness.

RESULTS

Around three-quarters of the sample scored in the clinically significant range for current neurobehavioural impairment. They also reported high levels of impairment when rating retrospectively for the period before they were homeless. The mean group IQ was below average at 88. Abuse or neglect during their upbringing was reported by 89% of the sample. Emotional abuse, emotional neglect, and physical neglect were all positively correlated with total FrSBe scores. Sexual abuse, emotional neglect, and physical neglect were all negatively correlated with IQ. The associations between trauma and IQ and neurobehavioural traits appear generally unrelated to the presence of substance misuse in the sample.

CONCLUSION

Our homeless sample displayed relatively low IQ with high levels of neurobehavioural impairment. Our evidence suggests that these neuropsychological factors may, in part, constitute a long-term consequence of childhood trauma.

Smoking cessation among sheltered homeless: a pilot

OBJECTIVE

To test the feasibility and effect of a smoking cessation intervention among sheltered homeless.

METHODS

Homeless smokers were enrolled in a 12-week group counseling program plus pharmacotherapy (n = 58).

RESULTS

The mean number of sessions attended was 7.2; most participants used at least one type of medication (67%); and 75% completed 12-week end-of-treatment surveys. Carbon-monoxide-verified abstinence rates at 12 and 24 weeks were 15.5% and 13.6% respectively.

CONCLUSION

Results support the feasibility of enrolling and retaining sheltered homeless in a smoking cessation program. Counseling plus pharmacotherapy options may be effective in helping sheltered homeless smokers quit.

A systematic review of cognitive deficits in homeless adults: implications for service delivery

OBJECTIVE

The primary goals of this systematic review were to assess studies of homeless adults and cognitive functioning, and to explore the clinical implications and potential impacts on social functioning of these cognitive deficits.

METHOD

The MEDLINE, CINAHL, EMBASE, PsycINFO, Applied Social Sciences Index and Abstracts, ERIC, Social Sciences Abstracts, Social Sciences Citation Index, Social Services Abstracts, and Sociological Abstracts databases were searched from 1970 (or their inception) to October 2007. Abstracts from 582 studies were screened and 22 studies were found to meet inclusion criteria (published in the English language, reported results of neuropsychological tests, or screening tests for cognitive dysfunction in homeless people aged 18 years or older). Two investigators independently reviewed each study and rated its quality based on well-defined criteria.

RESULTS

Ten studies were of good or fair quality. Studies that administered the Mini Mental State Examination indicate about 4% to 7% of homeless people exhibit global cognitive deficits. Focal deficits in verbal and visual memory, attention, speed of cognitive processing, and executive function were also apparent. No studies of the functional implications of cognitive deficits were found.

CONCLUSIONS

Cognitive deficits in homeless people likely have a significant mediating impact on the effectiveness of skills training and rehabilitation programs. Clinicians should be cognizant that cognitive deficits probably impair homeless patients' ability to maintain housing stability and follow treatment recommendations. Implications for housing options and health service delivery should also be considered. Research is lacking on interventions to improve cognitive functioning in the homeless.

The effect of traumatic brain injury on the health of homeless people

BACKGROUND

We sought to determine the lifetime prevalence of traumatic brain injury and its association with current health conditions in a representative sample of homeless people in Toronto, Ontario.

METHODS

We surveyed 601 men and 303 women at homeless shelters and meal programs in 2004-2005 (response rate 76%). We defined traumatic brain injury as any self-reported head injury that left the person dazed, confused, disoriented or unconscious. Injuries resulting in unconsciousness lasting 30 minutes or longer were defined as moderate or severe. We assessed mental health, alcohol and drug problems in the past 30 days using the Addiction Severity Index. Physical and mental health status was assessed using the SF-12 health survey. We examined associations between traumatic brain injury and health conditions.

RESULTS

The lifetime prevalence among homeless participants was 53% for any traumatic brain injury and 12% for moderate or severe traumatic brain injury. For 70% of respondents, their first traumatic brain injury occurred before the onset of homelessness. After adjustment for demographic characteristics and lifetime duration of homelessness, a history of moderate or severe traumatic brain injury was associated with significantly increased likelihood of seizures (odds ratio [OR] 3.2, 95% confidence interval [CI] 1.8 to 5.6), mental health problems (OR 2.5, 95% CI 1.5 to 4.1), drug problems (OR 1.6, 95% CI 1.1 to 2.5), poorer physical health status (-8.3 points, 95% CI -11.1 to -5.5) and poorer mental health status (-6.0 points, 95% CI -8.3 to -3.7).

INTERPRETATION

Prior traumatic brain injury is very common among homeless people and is associated with poorer health.

Cognitive Impairments and the Prevention of Homelessness: Research and Practice Review

Cognitive impairments can increase significantly a person's level of risk for becoming or remaining homeless. Five topics are explored that address these impairments in preventing homelessness: (1) the nature and estimated prevalence of cognitive impairments among people who are homeless, especially those with vulnerabilities like mental illness or substance abuse; (2) the multiple origins of these impairments; (3) how these impairments impact services for people at risk for homelessness; (4) good practice approaches to handling cognitive impairments in homeless shelters, supported housing programs, and other service systems for people at risk for homelessness; and, (5) important research and practice issues requiring further action.