Date Published: September 25, 2012
Publisher: Hindawi Publishing Corporation
Author(s): O. Olajumoke Oshinaike, A. Akinsegun Akinbami, O. Oluwadamilola Ojo, I. Frank Ojini, U. Njideka Okubadejo, A. Mustapha Danesi.
Introduction. HIV-associated neurocognitive disorder (HAND) remains common despite the availability of antiretroviral therapy. Routine screening will improve early detections. Objective. To compare the performance of the minimental state examination (MMSE) and international HIV dementia scale (IHDS) in assessing neurocognitive function in HIV/AIDS patients on antiretroviral therapy. Methods. A case-control study of 208 HIV-positive and 121 HIV-negative individuals. Baseline demographic data were documented and cognitive function assessed using the two instruments. CD4 cell counts were recorded. Results. Cases comprised 137 females and 71 males. Controls were 86 females and 35 males. Mean MMSE score of cases was 27.7 ± 1.8 compared to 27.8 ± 1.3 in controls (P = 0.54). Mean IHDS score in cases was 8.36 ± 3.1 compared to 10.7 ± 0.9 in controls (P < 0.001). Using the MMSE scale, 6 cases but no controls had HAND (P = 0.09). Using the IHDS, 113 (54.3%) had HAND compared with 10 (8.3%) controls (P < 0.0001). Using IHDS, 56.5% cases with CD4 count > 200 had HAND compared with 92.5% with CD4 count < 200 (P < 0.001). Conclusion. These findings indicate that the IHDS detects higher rates of HAND and may identify HIV/AIDS patients who require further cognitive assessment using more robust assessment batteries.
HIV-associated neurocognitive disorder is often encountered in HIV infection despite the use of potent antiretroviral therapy. The spectrum ranges from mild and asymptomatic neurocognitive impairment (ANI), minor neurocognitive disorder (MND), to the more severe HIV-associated dementia (HAD) . ANI is characterized by asymptomatic or unrecognized neurocognitive impairment that may go unnoticed except specifically screened for, and individuals with ANI are more likely to progress to more severe forms of cognitive dysfunction. The essential features of MND are impaired cognitive or behavioral function in at least 2 domains (e.g., impaired attention-concentration, mental slowing, abnormal memory or other cognitive functions, slowed movements, incoordination, personality change, irritability, and emotional lability). In contrast to ANI, these abnormalities typically impair work-related function or activities of daily living, albeit mildly. MND is associated with shortened survival, reduced adherence with antiretroviral therapy, and problems with employability, and its presence is predictive of HAD. HAD represents the most severe form of cognitive dysfunction, with significant functional impairments, and is synonymous with HIV encephalopathy and AIDS dementia complex (ADC). ADC is one of the most common central nervous system complications of late HIV infection occurring in 15–20% of patients before the introduction of HAART [2, 3].
There are few studies corroborating the superiority of the International HIV Dementia Scale over the MiniMental State Examination for assessment of HAND in persons with HIV via direct comparative studies and employing a control group. The main findings from our study are that the IHDS detects a higher proportion of persons with HAND in HIV, affording an advantage for more intensive evaluation and early interventions to improve quality of life. Although extensive neuropsychological testing using a combination of tests is regarded as the “gold standard” for cognitive assessment, the IHDS offers an advantage in the “real-world” clinical setting due to the ease of administration and can thus serve as an indicator of the need for further assessment and also serve as a monitoring tool in routine practice. The MMSE scale was only able to weakly distinguish HIV cases from controls with respect to occurrence of HAND. This reinforces previous observations alluding to its lack of sensitivity to sub-cortical cognitive dysfunction. Skinner et al. compared the performance of the original HIV dementia scale (HDS), IHDS, and MMSE scales against other neuro-cognitive batteries in assessing cognitive dysfunction in HIV patients and also demonstrated the inferiority of MMSE in contrast to the HDS and IHDS. This may be explained by the ability of the IHDS to screen for psychomotor speed (in addition to attention/working memory, executive functioning, memory, and verbal/language), an aspect that is not included in the MMSE scale. Also, literacy level and language comprehension impair the MMSE, thus further limiting its application. The low mean test scores in the control groups may be due to bias as MMSE scores have been shown to be affected by age, sex, lower education level and sociocultural background thereby leading to improper classification of individuals .
Our study has added to the body of evidence encouraging the use of the IHDS as a screening instrument in the real-world clinical scenario of HIV/AIDS management, and we reemphasize that its intrinsic ability to reveal even mild cognitive impairment amenable to earlier intervention more than compensates for the possibility of a lower specificity. Incorporation of variables to determine affectation of activities of daily living into the original design of these instruments may assist in proper classification of patients especially in regions where more robust batteries are unavailable. With the accumulating evidence that standard HAART regimens are unable to fully reverse HAND and the unclear benefits of CNS-penetrant antiretroviral drugs even in the setting of long-term plasma viral suppression, there is a need for randomized prospective trials to explore the role of other adjuvant and neuroprotective therapies.