Journal of clinical and experimental neuropsychology, 2015
Within-person variability in cognitive performance is related to neurological integrity, but the ... more Within-person variability in cognitive performance is related to neurological integrity, but the association with functional abilities is less clear. The primary aim of this study was to examine the association between cognitive dispersion, or within-person variability, and everyday multitasking and the way in which these variables may influence performance on a naturalistic assessment of functional abilities. Participants were 156 community-dwelling adults, age 50 or older. Cognitive dispersion was calculated by measuring within-person variability in cognitive domains, established through principal components analysis. Path analysis was used to determine the independent contribution of cognitive dispersion to functional ability, mediated by multitasking. Results of the path analysis revealed that the number of subtasks interweaved (i.e., multitasked) mediated the association between cognitive dispersion and task sequencing and accuracy. Although increased multitasking was associate...
The Wide Range Achievement Test, 3rd edition, Reading Recognition subtest (WRAT-3 RR) is an estab... more The Wide Range Achievement Test, 3rd edition, Reading Recognition subtest (WRAT-3 RR) is an established measure of premorbid ability. Furthermore, its long-term reliability is not well documented, particularly in diverse populations with CNS-relevant disease. We examined test-retest reliability of the WRAT-3 RR over time in an HIV+ sample of predominantly racial/ethnic minority adults. Participants (N = 88) completed a comprehensive neuropsychological battery, including the WRAT-3 RR, on at least two separate study visits. Intraclass correlation coefficients (ICCs) were computed using scores from baseline and follow-up assessments to determine the test-retest reliability of the WRAT-3 RR across racial/ethnic groups and changes in medical (immunological) and clinical (neurocognitive) factors. Additionally, Fisher's Z tests were used to determine the significance of the differences between ICCs. The average test-retest interval was 58.7 months (SD = 36.4). The overall WRAT-3 RR test-retest reliability was high (r = .97, p < .001) and remained robust across all demographic, medical, and clinical variables (all r's > .92). ICCs did not differ significantly between the subgroups tested (all Fisher's Z p's > .05). Overall, this study supports the appropriateness of word-reading tests, such as the WRAT-3 RR, for use as stable premorbid IQ estimates among ethnically diverse groups. Moreover, this study supports the reliability of this measure in the context of change in health and neurocognitive status and in lengthy inter-test intervals. These findings offer strong rationale for reading as a "hold" test, even in the presence of a chronic, variable disease such as HIV.
This study examined the association between trauma exposure, PTSD, suicide attempts, and other ps... more This study examined the association between trauma exposure, PTSD, suicide attempts, and other psychopathology among 316 racially/ethnically diverse HIV-infected men and women who underwent semi-structured psychiatric assessment. In addition, the role of psychological resilience in trauma exposure was examined in the context of neurological symptoms and functional status. Nearly half (47.8%; 151/316) of the participants reported trauma exposure, of which 47.0% (71/151) developed PTSD. Among trauma-exposed individuals, those with a current psychiatric diagnosis reported more neurological symptoms and lower functional status. Trauma exposure without PTSD was associated with a higher rate of panic disorder and substance-induced mental disorders. Trauma-exposed individuals who did not develop PTSD were less likely than those who reported no trauma exposure to meet criteria for major depressive disorder (MDD). Trauma exposure, MDD, borderline personality disorder, and substance-induced mental disorders were independently associated with increased odds of suicide attempt. These results indicate that co-morbid psychiatric disorders are common among trauma exposed individuals with a history of PTSD, but those with trauma exposure who do not develop PTSD are less likely to experience MDD. The role of other co-morbid psychopathologies in the genesis of suicidal behavior among individuals living with HIV deserves further study.
Introduction: It is unclear whether or to what degree literacy, aging, and other neurologic abnor... more Introduction: It is unclear whether or to what degree literacy, aging, and other neurologic abnormalities relate to cognitive deficits among people living with HIV/AIDS in the combined antiretroviral therapy (CART) era. The primary aim of this study was to simultaneously examine the association of age, HIV-associated motor abnormalities, major depressive disorder, and reading level with information processing speed, learning, memory, and executive functions, and to determine whether processing speed mediated any of the relationships between cognitive and noncognitive variables. Method: Participants were 186 racially and ethnically diverse men and women living with HIV/AIDS who underwent comprehensive neurological, neuropsychological, and medical evaluations. Structural equation modeling was utilized to assess the extent to which information processing speed mediated the relationship between age, motor abnormalities, major depressive disorder, and reading level with other cognitive abilities. Results: Age, motor dysfunction, reading level, and current major depressive disorder were all significantly associated with information processing speed. Information processing speed fully mediated the effects of age on learning, memory, and executive functioning and partially mediated the effect of major depressive disorder on learning and memory. The effect of motor dysfunction on learning and memory was fully mediated by processing speed. Conclusions: These findings provide support for information processing speed as a primary deficit, which may account, at least in part, for many of the other cognitive abnormalities recognized in complex HIV/AIDS populations. The association of age and information processing speed may account for HIV/ aging synergies in the generation of CART-era cognitive abnormalities.
Major depressive disorder (MDD), cognitive symptoms, and mild cognitive deficits commonly occur i... more Major depressive disorder (MDD), cognitive symptoms, and mild cognitive deficits commonly occur in HIV-infected individuals, despite highly active antiretroviral therapies. In this study, we compared neuropsychological performance and cognitive symptoms of 191 HIV-infected participants. Results indicated that participants with a formal diagnosis of current MDD performed significantly worse than participants without MDD in all seven neuropsychological domains evaluated, with the largest effect sizes in information processing speed, learning, and memory. In addition, a brief assessment of cognitive symptoms, derived from a comprehensive neuromedical interview, correlated significantly with neurocognitive functioning. Participants with MDD reported more cognitive symptoms and showed greater neurocognitive deficits than participants without MDD. These findings indicate that HIV-infected adults with MDD have more cognitive symptoms and worse neuropsychological performance than HIV-infected individuals without MDD. The results of this study have important implications for the diagnosis of HIV-associated neurocognitive disorders (HAND).
While distal sensory polyneuropathy (DSP) is the most common neurological condition associated wi... more While distal sensory polyneuropathy (DSP) is the most common neurological condition associated with HIV, causing nerve damage in upper and lower extremities, its impact on neuropsychological test performance is unclear. In this study, we analyzed baseline data for 278 HIV-infected participants with comprehensive neurological and neurocognitive evaluations to examine the contribution of DSP and anatomic distribution of neuropathic signs (upper extremity or lower extremity) on standardized domain scores. We found that participants with DSP performed significantly worse in multiple domains containing timed psychomotor tests (i.e., motor, information processing speed and executive functioning). With regard to executive functioning, differences were limited to a test with a motor component (Trail Making Test, Part B). The group with clinically detectable neuropathic signs in the upper extremities and the group with signs limited to the lower extremities both performed worse in the motor domain than the group without DSP. Participants with DSP demonstrated a unique pattern of impairment limited to neuropsychological domains with timed psychomotor tests. These results suggest that caution should be used in interpretation of neuropsychological tests in patients with DSP, as some abnormalities may be exacerbated by peripheral nervous system pathology. (JINS, 2012, 18, 898-907)
Background: To determine how serious a confound substance use (SU) might be in studies on HIV-ass... more Background: To determine how serious a confound substance use (SU) might be in studies on HIV-associated neurocognitive disorder (HAND), we examined the relationship of SU history to neurocognitive impairment (NCI) in participants enrolled in the Central Nervous System HIV Antiretroviral Therapy Effects Research study.
Journal of clinical and experimental neuropsychology, 2015
Within-person variability in cognitive performance is related to neurological integrity, but the ... more Within-person variability in cognitive performance is related to neurological integrity, but the association with functional abilities is less clear. The primary aim of this study was to examine the association between cognitive dispersion, or within-person variability, and everyday multitasking and the way in which these variables may influence performance on a naturalistic assessment of functional abilities. Participants were 156 community-dwelling adults, age 50 or older. Cognitive dispersion was calculated by measuring within-person variability in cognitive domains, established through principal components analysis. Path analysis was used to determine the independent contribution of cognitive dispersion to functional ability, mediated by multitasking. Results of the path analysis revealed that the number of subtasks interweaved (i.e., multitasked) mediated the association between cognitive dispersion and task sequencing and accuracy. Although increased multitasking was associate...
The Wide Range Achievement Test, 3rd edition, Reading Recognition subtest (WRAT-3 RR) is an estab... more The Wide Range Achievement Test, 3rd edition, Reading Recognition subtest (WRAT-3 RR) is an established measure of premorbid ability. Furthermore, its long-term reliability is not well documented, particularly in diverse populations with CNS-relevant disease. We examined test-retest reliability of the WRAT-3 RR over time in an HIV+ sample of predominantly racial/ethnic minority adults. Participants (N = 88) completed a comprehensive neuropsychological battery, including the WRAT-3 RR, on at least two separate study visits. Intraclass correlation coefficients (ICCs) were computed using scores from baseline and follow-up assessments to determine the test-retest reliability of the WRAT-3 RR across racial/ethnic groups and changes in medical (immunological) and clinical (neurocognitive) factors. Additionally, Fisher's Z tests were used to determine the significance of the differences between ICCs. The average test-retest interval was 58.7 months (SD = 36.4). The overall WRAT-3 RR test-retest reliability was high (r = .97, p < .001) and remained robust across all demographic, medical, and clinical variables (all r's > .92). ICCs did not differ significantly between the subgroups tested (all Fisher's Z p's > .05). Overall, this study supports the appropriateness of word-reading tests, such as the WRAT-3 RR, for use as stable premorbid IQ estimates among ethnically diverse groups. Moreover, this study supports the reliability of this measure in the context of change in health and neurocognitive status and in lengthy inter-test intervals. These findings offer strong rationale for reading as a "hold" test, even in the presence of a chronic, variable disease such as HIV.
This study examined the association between trauma exposure, PTSD, suicide attempts, and other ps... more This study examined the association between trauma exposure, PTSD, suicide attempts, and other psychopathology among 316 racially/ethnically diverse HIV-infected men and women who underwent semi-structured psychiatric assessment. In addition, the role of psychological resilience in trauma exposure was examined in the context of neurological symptoms and functional status. Nearly half (47.8%; 151/316) of the participants reported trauma exposure, of which 47.0% (71/151) developed PTSD. Among trauma-exposed individuals, those with a current psychiatric diagnosis reported more neurological symptoms and lower functional status. Trauma exposure without PTSD was associated with a higher rate of panic disorder and substance-induced mental disorders. Trauma-exposed individuals who did not develop PTSD were less likely than those who reported no trauma exposure to meet criteria for major depressive disorder (MDD). Trauma exposure, MDD, borderline personality disorder, and substance-induced mental disorders were independently associated with increased odds of suicide attempt. These results indicate that co-morbid psychiatric disorders are common among trauma exposed individuals with a history of PTSD, but those with trauma exposure who do not develop PTSD are less likely to experience MDD. The role of other co-morbid psychopathologies in the genesis of suicidal behavior among individuals living with HIV deserves further study.
Introduction: It is unclear whether or to what degree literacy, aging, and other neurologic abnor... more Introduction: It is unclear whether or to what degree literacy, aging, and other neurologic abnormalities relate to cognitive deficits among people living with HIV/AIDS in the combined antiretroviral therapy (CART) era. The primary aim of this study was to simultaneously examine the association of age, HIV-associated motor abnormalities, major depressive disorder, and reading level with information processing speed, learning, memory, and executive functions, and to determine whether processing speed mediated any of the relationships between cognitive and noncognitive variables. Method: Participants were 186 racially and ethnically diverse men and women living with HIV/AIDS who underwent comprehensive neurological, neuropsychological, and medical evaluations. Structural equation modeling was utilized to assess the extent to which information processing speed mediated the relationship between age, motor abnormalities, major depressive disorder, and reading level with other cognitive abilities. Results: Age, motor dysfunction, reading level, and current major depressive disorder were all significantly associated with information processing speed. Information processing speed fully mediated the effects of age on learning, memory, and executive functioning and partially mediated the effect of major depressive disorder on learning and memory. The effect of motor dysfunction on learning and memory was fully mediated by processing speed. Conclusions: These findings provide support for information processing speed as a primary deficit, which may account, at least in part, for many of the other cognitive abnormalities recognized in complex HIV/AIDS populations. The association of age and information processing speed may account for HIV/ aging synergies in the generation of CART-era cognitive abnormalities.
Major depressive disorder (MDD), cognitive symptoms, and mild cognitive deficits commonly occur i... more Major depressive disorder (MDD), cognitive symptoms, and mild cognitive deficits commonly occur in HIV-infected individuals, despite highly active antiretroviral therapies. In this study, we compared neuropsychological performance and cognitive symptoms of 191 HIV-infected participants. Results indicated that participants with a formal diagnosis of current MDD performed significantly worse than participants without MDD in all seven neuropsychological domains evaluated, with the largest effect sizes in information processing speed, learning, and memory. In addition, a brief assessment of cognitive symptoms, derived from a comprehensive neuromedical interview, correlated significantly with neurocognitive functioning. Participants with MDD reported more cognitive symptoms and showed greater neurocognitive deficits than participants without MDD. These findings indicate that HIV-infected adults with MDD have more cognitive symptoms and worse neuropsychological performance than HIV-infected individuals without MDD. The results of this study have important implications for the diagnosis of HIV-associated neurocognitive disorders (HAND).
While distal sensory polyneuropathy (DSP) is the most common neurological condition associated wi... more While distal sensory polyneuropathy (DSP) is the most common neurological condition associated with HIV, causing nerve damage in upper and lower extremities, its impact on neuropsychological test performance is unclear. In this study, we analyzed baseline data for 278 HIV-infected participants with comprehensive neurological and neurocognitive evaluations to examine the contribution of DSP and anatomic distribution of neuropathic signs (upper extremity or lower extremity) on standardized domain scores. We found that participants with DSP performed significantly worse in multiple domains containing timed psychomotor tests (i.e., motor, information processing speed and executive functioning). With regard to executive functioning, differences were limited to a test with a motor component (Trail Making Test, Part B). The group with clinically detectable neuropathic signs in the upper extremities and the group with signs limited to the lower extremities both performed worse in the motor domain than the group without DSP. Participants with DSP demonstrated a unique pattern of impairment limited to neuropsychological domains with timed psychomotor tests. These results suggest that caution should be used in interpretation of neuropsychological tests in patients with DSP, as some abnormalities may be exacerbated by peripheral nervous system pathology. (JINS, 2012, 18, 898-907)
Background: To determine how serious a confound substance use (SU) might be in studies on HIV-ass... more Background: To determine how serious a confound substance use (SU) might be in studies on HIV-associated neurocognitive disorder (HAND), we examined the relationship of SU history to neurocognitive impairment (NCI) in participants enrolled in the Central Nervous System HIV Antiretroviral Therapy Effects Research study.
Uploads
Papers by Robert Fellows