Action (verb) generation in HIV-1 infection

Highly active antiretroviral therapy-related effects on morphological connectivity in HIV

OBJECTIVE

Suboptimal concentration of the antiretroviral drug is insufficient to inhibit HIV destruction on brain structure and function due to the resistance of blood brain barrier. We aimed to investigate highly active antiretroviral therapy (HAART)-related effects on the morphological connectivity in people with HIV (PWH).

DESIGN

Case-control study.

METHODS

Fifty-five HAART-treated for more than 3 months and 54 untreated PWH, as well as 66 demographically matched healthy controls underwent a high-resolution 3D T1-weighted MRI. Individual-level morphological brain network based on gray matter volume of 90 brain regions was constructed and network topological properties were analyzed. Network-based statistics (NBS) was performed to identify sub-networks showing significant differences in morphological connectivity. Correlation and mediation analyses were employed to evaluate associations between the morphological properties and clinical variables of PWH.

RESULTS

Although PWH exhibited small-world architecture in their morphological brain networks, untreated PWH demonstrated altered network properties while HAART-treated PWH showed relatively similar network properties compared to healthy controls. Furthermore, HAART-related effects were mainly involved the bilateral putamen and left thalamus. The findings of NBS further indicated the cortico-striatum-thalamic-cortical loop was involved in the therapeutic-associated morphological network. The positive correlations between the HAART treatment and nodal degree and efficiency of the putamen were mediated by the number of CD4 + T lymphocytes.

CONCLUSIONS

The topological properties are recovered to normal in PWH after HAART and the effects induced by HAART are mostly within the cortical-subcortical circuit.

Cognitive Deficits: Verbal and Semantic Fluency in People Living with HIV and AIDS

BACKGROUND

Since the beginning of the HIV epidemic, the virus has taken millions of lives worldwide. The United Nations AIDS Fund's statistics reported that deaths caused by HIVrelated conditions and AIDS were about 39 million from the beginning of the epidemic to 2015. The united global efforts to fight the virus are considerably changing the indicators, such as mortality and morbidity, but the challenges remain. The total number of people living with HIV in Bulgaria as of 12th May, 2015, was 2,121. As of 30th November, 2016, the official data reported 2 460 people living with HIV. As of 13th February, 2017, 2 487 individuals were HIV-seropositive. Approximately 60% of people with HIV are prone to developing cognitive impairment due to the infection.

OBJECTIVE

This study aimed to know the level of cognitive deficiency, in particular, the verbal and semantic fluency of people living with HIV and AIDS.

METHODS

In this study, a comparative analysis was carried out. The Stewart test was used to compare the average independent samples. For clarity, the average values, the test statistics, and the estimated significance levels are presented in the tables. Additionally, a statistical mechanism of factor selection was used by the forward stepwise method. The Wilks' Lambda statistic reported values between 0 and 1, with values close to zero indicating good discrimination of the model.

RESULTS

According to this research, the HIV positives participants generated fewer verbs than the ones from the control group. The data were partially confirmed by the present study. There were differences in terms of both adjectives and nouns among people living with HIV and AIDS.

CONCLUSION

The study data proves that language deficits are detectable in neurocognitive testing of HIV. The overall hypothesis of the study has been confirmed. The language impairments are primarily qualitative and can be used as a marker for the initial and subsequent therapy assessment.

Factors associated with verbal fluency in older adults living with HIV in West Africa: A longitudinal study

OBJECTIVE

Verbal fluency decline, observed both in aging and HIV infection, has been related to lower quality of life. This study aimed to evaluate the factors associated with categorical fluency in people living with HIV (PLHIV) aged ≥60 years living in West Africa.

METHODS

In this longitudinal study, PLHIV aged ≥60 years, on antiretroviral therapy (ART) for ≥6 months were included in three clinics (two in Côte d'Ivoire, one in Senegal) participating in the West Africa International epidemiological Databases to Evaluate AIDS (IeDEA) collaboration. Categorical fluency was evaluated with the Isaacs Set Test at 60 s at baseline and 2 years later. Factors associated with verbal fluency baseline performance and annual rates of changes were evaluated using multivariate linear regression models.

RESULTS

Ninety-seven PLHIV were included with 41 of them (42%) having a 2-year follow-up visit. The median age was 64 (62-67), 45.4% were female, and 89.7% had an undetectable viral load. The median annual change in categorical fluency scores was -0.9 (IQR: -2.7 to 1.8). Low baseline categorical fluency performance and its decline were associated with older age and being a female. Low educational level was associated with low baseline categorical fluency performance but not with its decline. Categorical fluency decline was also associated with marital status and hypertension.

CONCLUSIONS

Among older West African PLHIV, usual socio-demographic variables and hypertension were the main factors associated with low categorical fluency performance and/or its decline. Interventions that focus on supporting cardiometabolic health are highly recommended to prevent cognitive disorders in PLHIV.

Cognitive Phenotypes of HIV Defined Using a Novel Data-driven Approach

The current study applied data-driven methods to identify and explain novel cognitive phenotypes of HIV. Methods: 388 people with HIV (PWH) with an average age of 46 (15.8) and median plasma CD4+ T-cell count of 555 copies/mL (79% virally suppressed) underwent cognitive testing and 3T neuroimaging. Demographics, HIV disease variables, and health comorbidities were recorded within three months of cognitive testing/neuroimaging. Hierarchical clustering was employed to identify cognitive phenotypes followed by ensemble machine learning to delineate the features that determined membership in the cognitive phenotypes. Hierarchical clustering identified five cognitive phenotypes. Cluster 1 (n=97) was comprised of individuals with normative performance on all cognitive tests. The remaining clusters were defined by impairment on action fluency (Cluster 2; n=46); verbal learning/memory (Cluster 3; n=73); action fluency and verbal learning/memory (Cluster 4; n=56); and action fluency, verbal learning/memory, and tests of executive function (Cluster 5; n=114). HIV detectability was most common in Cluster 5. Machine learning revealed that polysubstance use, race, educational attainment, and volumes of the precuneus, cingulate, nucleus accumbens, and thalamus differentiated membership in the normal vs. impaired clusters. The determinants of persistent cognitive impairment among PWH receiving suppressive treatment are multifactorial nature. Viral replication after ART plays a role in the causal pathway, but psychosocial factors (race inequities, substance use) merit increased attention as critical determinants of cognitive impairment in the context of ART. Results underscore the need for comprehensive person-centered interventions that go beyond adherence to patient care to achieve optimal cognitive health among PWH.

Neuropsychological functioning and cognitive reserve in newly HIV diagnosed antiretroviral-naïve South African adults from peri-urban and informal settlements

Despite lower incidences of HIV-associated dementia due to antiretroviral therapy, neuropsychological impairment (NPI) remains a persistent challenge in sub-Saharan Africa. Improving cognitive reserve (CR) can mitigate NPI, but there are few investigations on neuropsychological (NP) performance, and its association with CR in newly diagnosed ART-naïve HIV-positive individuals to inform early treatment strategies. A comprehensive battery of tests were administered to assess various NP domains (International HIV Dementia Scale [for memory, motor speed, psychomotor speed], Digit Span Test [for attention], Action Fluency Test [for language] and Clock Drawing Test [for executive/visuospatial function]), and CR (using Cognitive Reserve Index Questionnaire) among 211 newly diagnosed ART-naïve HIV-positive participants from two clinics that serve peri-urban and informal settlement communities in KwaZulu-Natal, South Africa. Regression models were fitted to assess the association between NP performance and CR controlling for socioeconomic and clinical factors. Test results revealed high levels of impairment across NP domains: language (96.7%), memory and psychomotor speed (82.5%), concentration (17.5%), executive function (15.2%) and visuo-spatial function (3.3%). Low CR and educational attainment were the only factors consistently associated with poor NP performance based on regression. High levels of impairment were found in certain NP domains in a relatively young group of newly diagnosed ART-naïve HIV-positive individuals. Residents of peri-urban and informal settlements face multitude of complex challenges in South Africa. An early multilevel intervention targeting clinical- (e.g. CR) and structural-level challenges (e.g. access to education) is needed for mitigating HIV-associated NPI and promoting long-term healthy living.

Driving habits, cognition, and health-related quality of life in middle-aged and older adults with HIV

Cognitive impairment is known to increase with aging in people living with HIV (PLWH). Impairment in cognitive domains required for safe driving may put PLWH at risk for poor driving outcomes, decreased mobility, and health-related quality of life (HRQoL). This study described the driving behaviors of middle-aged and older PLWH and examined correlations between driving behaviors and cognitive functioning (Aim 1), and driving behaviors and HRQoL domains (Aim 2). A sample of 260 PLWH ages 40 and older completed a comprehensive assessment including a battery of cognitive tests, an HRQoL measure, and a measure of self-reported driving habits. Associations between driving habits, cognitive function, and HRQoL domains were examined. While 212 (81.54%) participants reported currently driving, only 166 (63.85%) possessed a driver's license. Several significant correlations emerged between driving habits and both cognitive and HRQoL variables, with a general pattern suggesting that current greater driving exposure was associated with better cognitive functioning and HRQoL. Given consistent associations that emerged between the social functioning HRQoL domain and several driving habits, multivariable regression was conducted to examine the unique association between an index of greater driving exposure (i.e., days driven per week) and social functioning, adjusting for potential confounders (race, income, education, depression, and global cognition). Results showed that more days driven per week was a significant, independent correlate of higher social functioning. Understanding the factors underlying driving behaviors in PLWH may contribute to interventions to promote better mobility and improved access to care.

Neuropsychological Assessment: Past and Future

Neuropsychological assessment tools are the staple of our field. The development of standardized metrics sensitive to brain-behavior relationships has shaped the neuropsychological questions we can ask, our understanding of discrete brain functions, and has informed the detection and treatment of neurological disorders. We identify key turning points and innovations in neuropsychological assessment over the past 40-50 years that highlight how the tools used in common practice today came to be. Also selected for emphasis are several exciting lines of research and novel approaches that are underway to further probe and characterize brain functions to enhance diagnostic and treatment outcomes. We provide a brief historical review of different clinical neuropsychological assessment approaches (Lurian, Flexible and Fixed Batteries, Boston Process Approach) and critical developments that have influenced their interpretation (normative standards, cultural considerations, longitudinal change, common metric batteries, and translational assessment constructs). Lastly, we discuss growing trends in assessment including technological advances, efforts to integrate neuropsychology across disciplines (e.g., primary care), and changes in neuropsychological assessment infrastructure. Neuropsychological assessment has undergone massive growth in the past several decades. Nonetheless, there remain many unanswered questions and future challenges to better support measurement tools and translate assessment findings into meaningful recommendations and treatments. As technology and our understanding of brain function advance, efforts to support infrastructure for both traditional and novel assessment approaches and integration of complementary brain assessment tools from other disciplines will be integral to inform brain health treatments and promote the growth of our field. (JINS, 2017, 23, 778-790).

Increased subcortical neural activity among HIV+ individuals during a lexical retrieval task

BACKGROUND

Deficits in lexical retrieval, present in approximately 40% of HIV+ patients, are thought to reflect disruptions to frontal-striatal functions and may worsen with immunosuppression. Coupling frontal-striatal tasks such as lexical retrieval with functional neuroimaging may help delineate the pathophysiologic mechanisms underlying HIV-associated neurological dysfunction.

OBJECTIVE

We examined whether HIV infection confers brain functional changes during lexical access and retrieval. It was expected that HIV+ individuals would demonstrate greater brain activity in frontal-subcortical regions despite minimal differences between groups on neuropsychological testing. Within the HIV+ sample, we examined associations between indices of immunosuppression (recent and nadir CD4+ count) and task-related signal change in frontostriatal structures. Method16 HIV+ participants and 12 HIV- controls underwent fMRI while engaged in phonemic/letter and semantic fluency tasks. Participants also completed standardized measures of verbal fluency

RESULTS

HIV status groups performed similarly on phonemic and semantic fluency tasks prior to being scanned. fMRI results demonstrated activation differences during the phonemic fluency task as a function of HIV status, with HIV+ individuals demonstrating significantly greater activation in BG structures than HIV- individuals. There were no significant differences in frontal brain activation between HIV status groups during the phonemic fluency task, nor were there significant brain activation differences during the semantic fluency task. Within the HIV+ group, current CD4+ count, though not nadir, was positively correlated with increased activity in the inferior frontal gyrus and basal ganglia.

CONCLUSION

During phonemic fluency performance, HIV+ patients recruit subcortical structures to a greater degree than HIV- controls despite similar task performances suggesting that fMRI may be sensitive to neurocompromise before overt cognitive declines can be detected. Among HIV+ individuals, reduced activity in the frontal-subcortical structures was associated with lower CD4+ count.

Does previous presentation of verbal fluency tasks affect verb fluency performance?

Background

Performance on the verb fluency (VF) task may be influenced by administration procedures and demographic factors of each population.

Objective

The aim of this study was to verify whether the previous administration of semantic and phonemic verbal fluency tasks can influence performance on VF; and to analyze the correlation of VF performance with education, age and type of errors in Brazilian healthy elderly.

Methods

Sixty-two participants were subdivided into experimental (semantic and the phonemic fluency tasks were administered before the VF) and control groups (VF only). The total score and the types of errors on the VF task were determined. Additional information was computed for the correlational analysis.

Results

VF performance did not differ statistically between experimental and control groups, but correlated positively with education and negatively with intrusions.

Conclusion

The lack of influence of other verbal fluency tasks on performance of the VF task in elderly individuals allows the use of this order of administration. A strong influence of educational level on VF task performance reinforces the need for further studies in different populations.

A behavioral study of the nature of verb production deficits in Alzheimer's disease

Patients with Alzheimer's disease (AD) may experience greater difficulty with verb production than with noun production. In this study, we sought to assess the nature of verb production deficits in AD by using verb fluency and verb naming tasks. We designed two hypotheses for this verb deficit: (1) executive impairment drives the deficit; (2) semantic impairment drives the deficit. Thirty-five patients with AD and 35 matched healthy controls participated in the study. Both groups performed a verb naming task composed of 45 pictures (low-, medium-, and high-frequency subsets) and a verb fluency task (scored for total correct words and for mean word frequency). Patients with AD were equally impaired in verb naming and verb fluency, with an effect of disease severity on verb naming. Word frequency influenced verb naming, but not verb fluency, performance. Our results indicate that verb production deficits in AD seem to be driven more by semantic than by executive impairment.

Action verbal fluency in Parkinson’s patients

We compared the performance of 31 non-demented Parkinson´s disease (PD) patients to 61 healthy controls in an action verbal fluency task. Semantic and phonemic fluencies, cognitive impairment and behavioural dysfunction were also assessed. The mean disease duration of PD was 9.8 years (standard deviation (SD) = 6.13). There were no age (U = 899.5, p = 0.616), gender(chi-square = 0.00, p = 1.00) or literacy (U = 956, p = 0.96) differences between the two groups. A significant difference was observed between the two groups in the action verbal fluency task (U = 406.5, p < 0.01) that was not found in the other fluency tasks. The education level was the only biographical variable that influenced the action (verb) fluency outcomes, irrespective of disease duration. Our findings suggest a correlation between the disease mechanisms in PD and a specific verb deficit, support the validity of the action (verb) fluency as an executive function measure and suggest that this task provides unique information not captured with traditional executive function tasks.

Verb production tasks in the measurement of communicative abilities in aphasia

BACKGROUND

The neurofunctional correlates of verbs and nouns have been the focus of many theoretically oriented studies. In clinical practice, however, more attention is typically paid to nouns, and the relative usefulness of tasks probing nouns and verbs is unclear. The routine administration of tasks that use verbs could be a relevant addition to current batteries. Evaluating performance on both noun and verb tasks may provide a more reliable account of everyday language abilities than an evaluation restricted to nouns.

AIMS

To assess the benefits of administering verb tasks in addition to noun tasks, and their relation to three functional measures of language.

METHOD AND PROCEDURE

Twenty-one subjects with poststroke language disorders completed four picture-naming tasks and a role-playing test (Communicative Abilities in Daily Living, Second Edition, CADL-2), commonly used as measure of everyday language abilities. Two questionnaires (Communicative Effectiveness Index, CETI, and Communicative Activity Log, CAL) were completed by caregivers. Picture-naming tasks were matched for psycholinguistic variables to avoid lexicosemantic and morphosyntactic confounds.

RESULTS

No significant differences emerged across picture-naming tasks. Scores on the role-playing test and the two questionnaires differed; scores between the two questionnaires did not. The four naming tasks correlated significantly with CADL-2, CETI, and CAL. The strength of the correlation with CADL-2 was significantly greater for Naming Finite Verbs than for Object Naming. Thirteen participants showed no differences in performance between tasks, 6 fared significantly worse on verb tasks than on Object Naming, 1 fared better at Naming Finite Verbs though his performance was poor overall, and 1 was significantly more impaired on verbs.

CONCLUSIONS

Performance on tasks that use verbs, and especially Naming Finite Verbs, may provide a more accurate estimate of language abilities in daily living than Object Naming alone. Administering both verb and noun tasks may be recommended in clinical practice.

Impact of human immunodeficiency virus on neurocognition and risky behaviors in young adults

Previous studies have identified cognitive impairments due to human immunodeficiency virus (HIV) in adults. However, few studies have examined the impact of HIV on cognition in young adults (18-24 years old). Yet, this group is one of the largest populations of individuals with new HIV infection. Young adulthood is also an important developmental window because the brain has not fully matured and individuals are prone to engage in risky behavior. The purpose of the present study was to examine the impact of HIV on neurocognition and risky behaviors. We hypothesized that HIV+ young adults (n = 23) would exhibit greater cognitive impairment and risky behaviors compared to seronegative controls (n = 21). In addition, we predicted that self-reported risky behavior as assessed by the Risk Assessment Battery (RAB) would covary with cognitive performances. Results revealed poorer executive function in HIV+ young adults compared to seronegative (HIV-) controls. HIV+ young adults exhibited significantly greater risk scores on the RAB (p < 0.01) compared to HIV- young adults. However, there were no relationships between risky behavior and cognitive performance. Overall, our results suggest that HIV is associated with poorer cognition and increased risky behaviors in young adults.

The Basis and Applications of the Action Fluency and Action Naming Tasks

The Action Fluency (AF) and Action Naming (AN) are different tasks involving verb generation. Evidence indicates that verb tasks yield different information from that obtained with nouns.

Objective

This study aimed to analyze the information available in the scientific literature on the mechanism and clinical application of these tasks.

Methods

We carried out a systematic review of the literature and the findings were presented according to clinical studies and neuroimaging studies, and to the task in question.

Results

The literature contained a variety of relevant studies with different objectives, methodologies and populations. After the analysis (exclusion criteria) of the studies obtained by the search terms, only 40 studies were included in this review.

Conclusion

It was possible to conclude that AF and AN involve different brain processes, and although recruiting frontal areas and circuits, other areas are also critical. These tasks may be useful for differentiating Primary Progressive Aphasias; AF might represent a new measure of executive function; finally, both these tests can be used to provide a better understanding of cognitive processes and certain diseases.

Memory-based strategies for antiretroviral medication management: an evaluation of clinical predictors, adherence behavior awareness, and effectiveness

"Forgetting" is the most commonly endorsed reason for missing an antiretroviral therapy (ART) dose, yet little is known about the prevalence, predictors, and effectiveness of the mnemonic strategies to support ART adherence. The current study assessed 28 self-reported memory-based medication strategies in 233 HIV-infected individuals with 30-day ART adherence measured via the medication event monitoring system. Participants endorsed using multiple (8.7 ± 5.6) strategies with the most common being internally-driven. More frequent strategy use was uniquely associated with affective distress, dependent daily functioning, higher non-ART pill burden, and poorer ART adherence. Individuals who used strategies frequently, but perceived them as minimally effective, had more affective, physical, and functional distress. More frequent strategy use was associated with worse ART adherence and was unrelated to perceived effectiveness. Primary reliance on internally-based mnemonic strategies may reflect a lack of awareness of adherence behaviors and may be insufficient to support optimal ART adherence in vulnerable populations.

Aging, prospective memory, and health-related quality of life in HIV infection

HIV infection and older age are each independently associated with lower health-related quality of life (HRQoL) and deficits in prospective memory (PM), which is a distinct aspect of cognition involving the ability to "remember to remember" to do something at a future occasion. The present study investigated associations between PM and HRQoL in 72 older (≥ 50 years) and 41 younger (≤ 40 years) HIV-infected adults. Self-reported PM complaints predicted HRQoL across the entire sample, but there was a significant interaction between performance-based PM and age group on HRQoL, such that lower time-based PM was associated with lower HRQoL only in the younger cohort. Within the younger group, time-based and self-reported PM significantly predicted mental HRQoL independent of other risk factors (e.g. depression). These findings suggest that PM plays a unique role in HRQoL outcomes among younger persons living with HIV infection and support the examination of other age-related factors (e.g. effective use of compensatory strategies) that may regulate the adverse impact of PM on everyday functioning.

Script generation of activities of daily living in HIV-associated neurocognitive disorders

Script generation describes one's ability to produce complex, sequential action plans derived from mental representations of everyday activities. The aim of this study was to assess the effect of human immunodeficiency virus (HIV) infection on script generation performance. Sixty HIV+ individuals (48% of whom had HIV-associated neurocognitive disorders [HAND]) and 26 demographically comparable HIV- participants were administered a novel, standardized test of script generation, which required participants to verbally generate and organize the necessary steps for completing six daily activities. HAND participants evidenced significantly more total errors, intrusions, and script boundary errors compared to the HIV- sample, indicating difficulties inhibiting irrelevant actions and staying within the prescribed boundaries of scripts, but had adequate knowledge of the relevant actions required for each script. These findings are generally consistent with the executive dysfunction and slowing common in HAND and suggest that script generation may play a role in everyday functioning problems in HIV.

Are time- and event-based prospective memory comparably affected in HIV infection?

According to the multi-process theory of prospective memory (ProM), time-based tasks rely more heavily on strategic processes dependent on prefrontal systems than do event-based tasks. Given the prominent frontostriatal pathophysiology of HIV infection, one would expect HIV-infected individuals to demonstrate greater deficits in time-based versus event-based ProM. However, the two prior studies examining this question have produced variable results. We evaluated this hypothesis in 143 individuals with HIV infection and 43 demographically similar seronegative adults (HIV-) who completed the research version of the Memory for Intentions Screening Test, which yields parallel subscales of time- and event-based ProM. Results showed main effects of HIV serostatus and cue type, but no interaction between serostatus and cue. Planned pair-wise comparisons showed a significant effect of HIV on time-based ProM and a trend-level effect on event-based ProM that was driven primarily by the subset of participants with HIV-associated neurocognitive disorders. Nevertheless, time-based ProM was more strongly correlated with measures of executive functions, attention/working memory, and verbal fluency in HIV-infected persons. Although HIV-associated deficits in time- and event-based ProM appear to be of comparable severity, the cognitive architecture of time-based ProM may be more strongly influenced by strategic monitoring and retrieval processes.

Action (verb) fluency in schizophrenia: getting a grip on odd speech

BACKGROUND

Formal thought disorder (TD) is a key symptom of schizophrenia with a significant impact on interpersonal relationships. Current cognitive models emphasize disordered language functioning and abnormalities accessing semantic representations. The cortical mechanisms for language and motor function are closely linked, hence action-related language may be impaired in TD, yet existing studies have focussed exclusively on object (noun) rather than action (verb) semantics.

METHOD

In order to examine this issue both action (verb) and traditional semantic (tools, fruits, musical instruments) and phonological (FAS) fluency tasks were completed by individuals with schizophrenia (N=53) and healthy controls (N=69). Fluency performance was measured as the total number of correct words generated in 60s. The Schizotypal Personality Questionnaire (SPQ) was used to index odd and disorganized speech, as well as positive and negative symptoms.

RESULTS

Fluency on all tasks was impaired in schizophrenia, compared to controls, with a similar effect size. Within the schizophrenia group Odd Speech was correlated with poor fluency for actions, tools and musical instruments but not fruit or phonological fluency. These action-related fluency deficits were also correlated with Constricted Affect and Social Anxiety but not with Unusual Perceptions/Odd Beliefs.

CONCLUSION

These results point to a unique connection and possible common aetiology between action fluency and odd speech in schizophrenia rather than a general impairment in language/executive functions common to fluency tasks. The findings provide the first evidence of a specific role of action-based language production deficits in TD together with a joint effect on social interaction skills.

Structural gray and white matter changes in patients with HIV

In this cross-sectional study we used magnetic resonance imaging (MRI)-based voxel based morphometry (VBM) in a sample of HIV positive patients to detect structural gray and white matter changes. Forty-eight HIV positive subjects with (n = 28) or without (n = 20) cognitive deficits (mean age 48.5 ± 9.6 years) and 48 age- and sex-matched HIV negative controls underwent MRI for VBM analyses. Clinical testing in HIV patients included the HIV dementia scale (HDS), Unified Parkinson's Disease Rating Scale (UPDRS) and the grooved pegboard test. Comparing controls with HIV positive patients with cognitive dysfunction (n = 28) VBM showed gray matter decrease in the anterior cingulate and temporal cortices along with white matter reduction in the midbrain region. These changes were more prominent with increasing cognitive decline, when assigning HIV patients to three cognitive groups (not impaired, mildly impaired, overtly impaired) based on performance in the HIV dementia scale. Regression analysis including all HIV positive patients with available data revealed that prefrontal gray matter atrophy in HIV was associated with longer disease duration (n = 48), while motor dysfunction (n = 48) was associated with basal ganglia gray matter atrophy. Lower CD4 cell count (n = 47) correlated with decrease of occipital gray matter. Our results provide evidence for atrophy of nigro-striatal and fronto-striatal circuits in HIV. This pattern of atrophy is consistent with motor dysfunction and dysexecutive syndrome found in HIV patients with HIV-associated neurocognitive disorder.

Antiretroviral adherence and the nature of HIV-associated verbal memory impairment

The authors investigated the relationship between antiretroviral adherence and HIV-associated verbal memory impairment. HIV-positive participants demonstrated poorer verbal memory than HIV-negative participants. Both good (≥90%) and poor (<90%) adherers displayed encoding deficits as compared with controls, but only poor adherers exhibited retrieval deficits. Encoding deficits primarily accounted for reduced delayed recall in good adherers, but both encoding and retrieval deficits accounted for reduced delayed recall in poor adherers. The retrieval difference between the adherence groups might be explained by a neuroprotective effect of good antiretroviral adherence or preexisting HIV-related retrieval deficits that result in poorer adherence.

Reduced verbal fluency for proper names in nondemented patients with Parkinson's disease: a quantitative and qualitative analysis

There has been an increasing interest within neuropsychology in comparing verbal fluency for different grammatical classes (e.g., verb generation vs. noun generation) in neurological populations, including Parkinson's disease (PD). However, to our knowledge, few studies have compared verbal fluency for common nouns and proper names in PD. Common nouns and proper names differ in terms of their semantic characteristics, as categories of common nouns are organized hierarchically based on semantics, while categories of proper nouns lack a well-defined semantic organization. In addition, there is accumulating evidence that the retrieval of these distinct grammatical classes are subserved by somewhat distinct neural systems. Given that verbal fluency deficits are among the first impairments to emerge in PD, and that such deficits are predictors of future cognitive decline, it is important to examine all aspects of verbal fluency in this population. For the current study, we compared the performance of a group of 32 nondemented PD patients with 32 healthy participants (HP) on verbal fluency tasks for common nouns (animals) and proper names (boys' first names). A significant interaction between verbal fluency task and diagnostic status emerged, as the PD group performed significantly worse on only the proper name fluency task. This finding may reflect the absence of well-defined semantic organization that structures the verbal search for first names, thus placing a greater onus on strategic or "executive" verbal retrieval processes.

Action versus animal naming fluency in subcortical dementia, frontal dementias, and Alzheimer's disease

Accumulating evidence indicates action naming may rely more on frontal-subcortical circuits, and noun naming may rely more on temporal cortex. Therefore, noun versus action fluency might distinguish frontal and subcortical dementias from cortical dementias primarily affecting temporal and/or parietal cortex such as Alzheimer's disease (AD). We hypothesized patients with subcortical dementia, e.g., normal pressure hydrocephalus (NPH) and patients with dementias predominantly affecting frontal cortex, e.g., behavioral variant frontotemporal dementia (bv-FTD) and progressive nonfluent aphasia (PNFA) have more difficulty on action fluency versus noun fluency (e.g., animal naming). Patients with AD, who have temporo parietal cortical dysfunction, should have more difficulty on noun versus verb fluency. A total of 234 participants, including healthy controls (n = 20) and patients diagnosed with NPH (n =144), AD (n = 33), bv-FTD (n = 22) or PNFA (n =15) were administered animal fluency, action fluency, and letter fluency tasks, and the Mini-Mental State Examination (MMSE, to control for dementia severity). NPH and bv-FTD/PNFA patients had significantly higher MMSE scores and animal fluency than AD patients (after adjusting for age), but their action fluency tended to be lower than in AD. Only NPH and bvFTD/PNFA patients showed significantly lower action verb than animal fluency. Results provide novel evidence that action naming relies more on frontal-subcortical circuits while noun naming relies more on temporoparietal cortex, indicating action verb fluency may be more sensitive than noun fluency, particularly for detecting frontal-subcortical dysfunction.

HIV-associated deficits in action (verb) generation may reflect astrocytosis

Commensurate with the hypothesized neural dissociation between verb and noun generation, research in HIV infection shows that, relative to noun fluency, action (verb) fluency is disproportionately impaired, more strongly related to executive dysfunction, and more sensitive to declines in everyday functioning. However, whether the neurobiological correlates of HIV-associated deficits in verb and noun generation are separable have not heretofore been investigated. The present study examined the biomarker correlates of action and noun fluency in 74 participants with HIV infection. Biomarkers of viral burden, neuroaxonal damage, macrophage activation, neuroprotection, inflammation, and astrocytosis were measured in plasma and cerebrospinal fluid (CSF). Deficits in action, but not noun generation, were significantly associated with higher CSF levels of S100beta, a marker of astrocyte activation, even after controlling for antiretroviral therapy, current immune compromise, and general cognitive impairment. Concurrent validity for the frontal systems hypothesis of verb generation was provided by post hoc analyses demonstrating that S100beta was also associated with measures of executive functions, but not semantic memory or psychomotor speed. Overall, these findings suggest that HIV-associated impairment in action fluency, and executive dysfunction more generally, may reflect astrocytosis (i.e., elevated S100beta). Complementing the literature in HIV and other clinical populations with frontal systems involvement, these data also support the possible neurobiological dissociation of noun and verb generation.

Neurocognitive functioning in HIV-1 infection: effects of cerebrovascular risk factors and age

This study examined the interactive effects of cerebrovascular risks, advancing age, and HIV infection on neurocognition, and explored whether pharmacological treatment of cerebrovascular risk factors attenuated neurocognitive dysfunction. Participants included 98 HIV-seropositive adults (cerebrovascular risk: 23.5%; age > 50: 27.6%). Cerebrovascular risk was associated with slower processing speed even after controlling for age effects (b = -2.071; p =.04), and the interaction of age and cerebrovascular risk was associated with poorer verbal fluency (b = 1.276, p =.002). Participants with pharmacologically untreated cerebrovascular risk demonstrated reduced processing speed, learning/memory, and executive functioning relative to those on medication. Poor cerebrovascular health confers significant risk for HIV+ individuals, and this effect may be of greater consequence than advancing age. The cognitive impact of risk appears to be more pronounced in the absence of adequate pharmacological treatment.

Cognitive neuropsychology of HIV-associated neurocognitive disorders

Advances in the treatment of the human immunodeficiency virus (HIV) have dramatically improved survival rates over the past 10 years, but HIV-associated neurocognitive disorders (HAND) remain highly prevalent and continue to represent a significant public health problem. This review provides an update on the nature, extent, and diagnosis of HAND. Particular emphasis is placed on critically evaluating research within the realm of cognitive neuropsychology that aims to elucidate the component processes of HAND across the domains of executive functions, motor skills, speeded information processing, episodic memory, attention/working memory, language, and visuoperception. In addition to clarifying the cognitive mechanisms of HAND (e.g., impaired cognitive control), the cognitive neuropsychology approach may enhance the ecological validity of neuroAIDS research and inform the development of much needed novel, targeted cognitive and behavioral therapies.

Differential impairment in semantic, phonemic, and action fluency performance in Friedreich's ataxia: possible evidence of prefrontal dysfunction

This study examined phonemic (letters), semantic (animals) and action verbal fluency cues in twenty-four patients with FRDA, and twenty matched healthy control subjects. The Action Fluency Test (AFT) is a newly-developed verbal fluency cue that consists in asking the subject to rapidly generate verbs. Given the high presence of dysarthria and cognitive slowness in FRDA patients, control tasks were administered in order to dissociate motor/articulatory impairment and cognitive slowness from verbal fluency deficit. Results showed that patients and control subjects performed similarly on the semantic fluency task. In contrast, patients performed significantly poorer on phonemic and action fluency tests. Correlational analyses showed that the deficits cannot be attributed to dysarthria or cognitive slowness. Although executive processes are necessary for initiating and monitoring all verbal fluency tasks, phonemic and action fluency may place a greater burden on strategic processes, given that they require a more unusual type of lexicon search. Thus, the deficits found occur in tasks that require greater executive/prefrontal control. This impairment might be the result of an affectation of cerebellum-prefrontal cortex connections, although the possibility of a primary prefrontal dysfunction remains to be investigated.

Neurocognitive Effects of Methamphetamine: A Critical Review and Meta-analysis

This review provides a critical analysis of the central nervous system effects of acute and chronic methamphetamine (MA) use, which is linked to numerous adverse psychosocial, neuropsychiatric, and medical problems. A meta-analysis of the neuropsychological effects of MA abuse/dependence revealed broadly medium effect sizes, showing deficits in episodic memory, executive functions, information processing speed, motor skills, language, and visuoconstructional abilities. The neuropsychological deficits associated with MA abuse/dependence are interpreted with regard to their possible neural mechanisms, most notably MA-associated frontostriatal neurotoxicity. In addition, potential explanatory factors are considered, including demographics (e.g., gender), MA use characteristics (e.g., duration of abstinence), and the influence of common psychiatric (e.g., other substance-related disorders) and neuromedical (e.g., HIV infection) comorbidities. Finally, these findings are discussed with respect to their potential contribution to the clinical management of persons with MA abuse/dependence.

A Temporal Lobe Factor in Verb Fluency

Verb fluency requires self-sustained verb retrieval. The brain correlates of this task are virtually unknown. We investigated the relations between verb and noun (semantic) fluency and regional brain perfusion in subjects with varying degrees of cognitive decline, ranging from very mild subjective impairment to Alzheimer's disease (AD). Data consisted of single-photon emission computed tomography (SPECT) data and temporally resolved verb and noun fluency scores from 93 participants. Impaired verb fluency was predicted by a temporal lobe hypoperfusion factor and low education, whereas high age and low perfusion in the parietotemporal-occipital region predicted impaired noun fluency. Analysis of perfusion within the temporal region indicated primary involvement of the temporal pole and medial temporal lobe in AD. This might reflect pathology of the anterior parahippocampal region, which appears early in neurodegenerative disease. Although temporal lobe structures have not usually been implicated in verb processing, early temporal pathology thus appears to contribute to impaired verb fluency in cognitive decline.

Verbal fluency in HIV infection: a meta-analytic review

Given the largely prefrontostriatal neuropathogenesis of HIV-associated neurobehavioral deficits, it is often presumed that HIV infection leads to greater impairment on letter versus category fluency. A meta-analysis of the HIV verbal fluency literature was conducted (k = 37, n = 7110) to assess this hypothesis and revealed generally small effect sizes for both letter and category fluency, which increased in magnitude with advancing HIV disease severity. Across all studies, the mean effect size of category fluency was slightly larger than that of letter fluency. However, the discrepancy between category and letter fluency dissipated in a more conservative analysis of only those studies that included both tests. Thus, HIV-associated impairments in letter and category fluency are of similar magnitude, suggesting that mild word generation deficits are evident in HIV, regardless of whether traditional letter or semantic cues are used to guide the word search and retrieval process.

Action (verb) fluency predicts dependence in instrumental activities of daily living in persons infected with HIV-1

Inspired by the hypothesized neural dissociation between the retrieval of nouns and verbs, several studies now support the construct validity of Action (verb) Fluency as a measure of frontostriatal systems function. Relative to traditional noun- and letter-cued verbal fluency tests, Action Fluency is more sensitive to HIV-1-associated neuropsychological impairment, which may reflect inefficiencies engaging motor representations during action retrieval in this population. Accordingly, impaired Action Fluency might adversely impact instrumental activities of daily living (IADL) by disrupting the production and organization of script-based action schemas upon which successful IADL performance depends. The present study thus sought to evaluate the ecological validity of Action Fluency as a predictor of IADL among persons with HIV-1 infection. Action, Letter (FAS), and Noun (animal) fluency were compared in 21 HIV-1-infected participants with self-reported IADL dependence relative to 76 demographically comparable HIV-1-infected participants who reported no IADL declines. Results revealed significant between-group differences in Action and Letter Fluency, but not Noun Fluency. Action Fluency achieved an overall hit rate of 76% and was more sensitive than Letter Fluency in classifying IADL dependent participants. Individuals with impaired Action Fluency performance had a fivefold risk of concurrent IADL dependence as compared to those who performed within normal limits. Findings suggest that Action Fluency may possess incremental ecological validity in the identification of HIV-1-associated neurocognitive disorders.

To mind the mind: an event-related potential study of word class and semantic ambiguity

The goal of this study was to jointly examine the effects of word class, word class ambiguity, and semantic ambiguity on the brain response to words in syntactically specified contexts. Four types of words were used: (1) word class ambiguous words with a high degree of semantic ambiguity (e.g., 'duck'); (2) word class ambiguous words with little or no semantic ambiguity (e.g., 'vote'); (3) word class unambiguous nouns (e.g., 'sofa'); and (4) word class unambiguous verbs (e.g., 'eat'). These words were embedded in minimal phrases that explicitly specified their word class: "the" for nouns (and ambiguous words used as nouns) and "to" for verbs (and ambiguous words used as verbs). Our results replicate the basic word class effects found in prior work (Federmeier, K.D., Segal, J.B., Lombrozo, T., Kutas, M., 2000. Brain responses to nouns, verbs and class ambiguous words in context. Brain, 123 (12), 2552-2566), including an enhanced N400 (250-450 ms) to nouns compared with verbs and an enhanced frontal positivity (300-700 ms) to unambiguous verbs in relation to unambiguous nouns. A sustained frontal negativity (250-900 ms) that was previously linked to word class ambiguity also appeared in this study but was specific to word class ambiguous items that also had a high level of semantic ambiguity; word class ambiguous items without semantic ambiguity, in contrast, were more positive than class unambiguous words in the early part of this time window (250-500 ms). Thus, this frontal negative effect seems to be driven by the need to resolve the semantic ambiguity that is sometimes associated with different grammatical uses of a word class ambiguous homograph rather than by the class ambiguity per se.