The incidence of MCMD and HAD in the HAART era has not been precisely estimated. Prior to 1991, the incidence of HAD within 2 years of AIDS diagnosis was 7% per year (McArthur, 1994). Since the advent of HAART, the overall incidence of HIV-associated dementia has declined. A study of the incidence of CNS complications of HIV in the Multicenter AIDS Cohort (MACS) from 1990 through 1997 documented table 10.1. American Academy of Neurology Criteria for HIV-Associated Neurocognitive Disorders
HIV-1-Associated Dementia (HAD)*
Criteria for 1 and 2 must be met:
1. Scores 1 standard deviation (SD) below age- and education-adjusted norms on two of eight neuropsycholo-gical tests or 2 SD below the norms on one ofeight tests
2. Requires assistance or has difficulty (due to either physical or cognitive deficit) in at least one of the following instrumental activities of daily living: Using the telephone
Handling money Taking medication Performing light housekeeping Doing laundry Preparing meals Shopping for groceries Getting to places out of walking distance and must meet either 1 or 2 of the following:
1. Any impairment in the following: lower extremity strength, coordination, finger tapping, alternating hand movements, leg agility, or performance on grooved pegboard 2 SDs below mean (dominant hand)
2. Self-reported frequent depression that interferes with function, loss of interest in usual activities or emotional lability, or irritability
Staging of HAD: mild, moderate or severe, based on degree of functional deficit
HIV-Associated Minor Cognitive/Motor Disorder (MCMD) *
Does not meet criteria for HAD and meets 1 and 2 of the following:
1. Deficit in at least two of the following:
Mental slowing: digit symbol at least 1 SD below age- and education-adjusted norms Memory: Rey Auditory Verbal Learning Test
(total) at least 1 SD below norms Motor dysfunction: any impairment in finger tapping, or pronation or supination Incoordination: mild impairment in gait or clumsiness Emotional lability, or apathy or withdrawal and
2. Deficit in at least one of the role function measures attributed in part to cognitive function: Need for frequent rests
Cut down on amount of time in activities
Cannot perform activities as carefully as one would like Limited in work or activities Difficulty performing activities Require special assistance to perform activities
*Symptoms should not be exclusively caused by other etiologies, i.e., CNS opportunistic infections, systemic disease, substance abuse.
Source: Adapted from American Academy of Neurology AIDS Task Force, 1991.
a decline in probable or possible HAD from 30 cases per 1000 person-years to 17 per 1000 person-years (Sacktor et al., 2001a). CNS opportunistic infections including toxoplasmosis, cryptococcal meningitis, and lymphoma declined similarly during this time period. Researchers from Australia found a similar decline in CNS AIDS-defining illnesses (ADIs) between 1992 and 1997 (Dore et al., 1999). However, over this time period, they found that HAD comprised a greater proportion of new-onset ADIs, rising from 4.4% in 1992 to 6.5% in 1997. Further, the average CD4 count of patients with HAD increased from 70 cells/ml to 170 cells/ml during this time period. This relative rise in the proportion of ADIs that are HAD may be due to variable CNS penetration of antiretroviral medications. Thus, while HIV patients taking HAART may have enhanced immune function and survive longer without HIV-associated cognitive decline, the prevalence of all-cause dementia in HIV-infected patients likely has remained stable or increased.
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