HIV Dementia Scale and Psychomotor Slowing—The Best Methods in Screening for Neuro-AIDS
Publication: The Journal of Neuropsychiatry and Clinical Neurosciences
Abstract
The authors examined the correlation between Human Immunodeficiency Virus (HIV) Dementia Scale (HDS) and psychomotor tests, evaluating basal ganglia function in 266 HIV-seropositive, Caucasian, homosexual men. Fifty-five HIV-positive, patients with mild dementia (HDS score ≤10) showed significant slowing of most rapid alternating movements (MRAM) and significantly prolonged contraction times compared to 211 HIV-positive nondemented patients (HDS score >10). Motor performance correlated significantly with the time-dependent HDS subscores for psychomotor speed and construction and HDS sum score. In contrast to contraction times and MRAM, HDS scores also showed significant correlations to age, premorbid and actual intelligence, and duration of HIV seropositivity.
Human immunodeficiency virus type 1 (HIV) associated dementia is the predominant clinical manifestation of HIV in the brain. Human immunodeficiency virus associated dementia is defined by a clinical triad of 1) cognitive deficits, 2) disturbed motor function, and 3) emotional deficits.1 The HIV Dementia Scale (HDS)2 was originally designed explicitly to serve as a valid screening tool to identify HIV dementia and to monitor therapeutic effects3 on the central nervous system (CNS). Initially, the HDS was shown as superior to other widely used rapid screening tests (Mini-Mental State Examination [MMSE], Grooved Pegboard) and to be especially effective in asymptomatic and acquired immune deficiency syndrome (AIDS) defined, but nondemented patients. The HDS is comprised of four tasks that evaluate the domains of memory (recall of four items at 5 minutes), attention (antisaccadic errors), psychomotor speed (timed written alphabet), and construction (cube copy time). A subscore and sum score are calculated for each domain. For more details, see Power et al.2 Today it is common knowledge that psychomotor slowing (i.e., minor motor deficits) predicts dementia, AIDS, and death.4,5 Screening for early deficits and careful evaluation of psychomotor function are therefore essential. Psychomotor slowing can be quantified in various manners: with refined neuropsychological test batteries5–7 or by an electrophysiological motor test battery that describes basal ganglia motor function in HIV-1 infection8 and in other well defined basal ganglia diseases such as Parkinson’s disease,9 Wilson’s disease,10 and Huntington’s chorea.11 We, therefore, decided to explore the relation between HDS scores and psychomotor performance as assessed by our test battery.
METHOD
Patients
Between 1988 and September 30, 2002, a total of 2,436 HIV-seropositive patients were recruited consecutively. Assessment with the HDS was introduced in our department on February 2, 1999. We retrospectively selected all patients who were examined parallel to the HDS and the above mentioned electrophysiological test battery.8 Among patients who received regular follow up, only the first parallel evaluation of HDS and motor performance was analyzed. Only patients with sexually acquired HIV infection were included. Patients who acquired HIV by intravenous drug use were excluded in order to avoid any interference between past or ongoing drug use and test results. Patients with a migration background were also excluded to avoid any influence of different mother languages on the timed written alphabet section of the HDS. To control for potential gender differences, only male patients, who represent the majority of patients in our department, were included. Patients with clinically severe forms of HIV associated dementia were excluded as well as patients with CNS opportunistic infections, CNS lymphoma, or vacuolar myelopathy. Demographical data for all N=266 patients are presented in Table 1. Six men have died meanwhile. Stages of HIV-1 infection were grouped according to the current Centers for Disease Control (CDC) classification12 into non-AIDS or AIDS stages. On the basis of an HDS score ≤10, the HDS between AIDS patients with and without mild dementia is distinguishable in the original scale,2 and we divided patients into two groups accordingly. To assess premorbid verbal intelligence and actual nonverbal intelligence, the Mehrfachwortauswahltest (MWT-b)13 and Raven14 tests were performed in all patients.
Central Motor Testing
In 1987, central motor testing was established for HIV-1 (positive) patients in our department and includes analysis of the following:
1.
postural tremor of the outstretched hands [tremor peak frequency (TPF)];
2.
most rapid alternating movement (MRAM) of index finger;
3.
most rapid isometric contraction (extension) of index finger (MRC), including
4.
a. simple reaction time (RT); and
5.
b. contraction time
Methodological details were published earlier8,15: a lightweight accelerometer taped to the nail of each subject’s index finger was used for recording the TPF and the MRAM. To determine TPF, subjects were requested to hold their arms in a horizontal position, with their forearms fully pronated and fingers completely outstretched. Spectrum analysis was performed off-line, and the frequency of the dominant peak of the average spectrum was defined as TPF. To determine MRAM, subjects were requested to flex and extend their index finger at the metacarpophalangeal joint as rapidly as possible. For MRC recordings, the index finger was firmly attached to a force transducer. Subjects were asked to extend the finger immediately after hearing a “go” signal. The simple reaction time (RT) and the time between the onset of the contraction and the point at which it reached its maximum (contraction time) were recorded.
Statistical Analysis
Statistics were performed using the commercially available software package Statview for Windows, Version 5.0.1 (SAS Institutes Inc., Cary, N.C., 1998). Descriptive statistics were used to describe subjects and parameters. Unpaired t tests and contingency tables were used to test for differences between groups. Correlation analyses were used to describe the relationship between variables.
RESULTS
Table 1 provides the demographic data of each patient. Following the original HDS,2 patients were separated into those with an HDS score >10, considered to be asymptomatic, and those with an HDS score ≤10, considered mildly demented. Asymptomatic patients were significantly younger than patients with mild dementia. Both groups did not differ with regard to the mode of infection, duration of HIV seropositivity, CDC stages at the time of first examination, type of antiretroviral therapy, CD 4+ cell counts, and HIV plasma viral load. Patients scoring ≤10 showed a significantly lower premorbid verbal IQ (MWT-b) and actual nonverbal IQ (Raven).
In a second step, we compared the results of electrophysiological motor tests in both groups (Table 2). Patients considered mildly demented showed highly significantly prolonged contraction time for both hands and significant slowing of MRAM for both hands. Reaction time was prolonged only for the right hand, whereas there were no differences in tremor peak frequency.
In a third step, we sought to determine which subtest of the HDS correlated best with psychomotor performance, as described by our test battery. We focused on the two parameters significantly altered: contraction time and MRAM. The significance of correlations is presented in Table 3. We found significant correlations between contraction time and MRAM for the HDS sum score as well as for HDS psychomotor speed and HDS construction subtests but not for HDS memory and HDS attention.
Finally, we aimed to find which potential confounding factors might interfere with both HDS and psychomotor testing. We, therefore, correlated HDS scores (sum, psychomotor speed, construction) and contraction time and MRAM as dependent variables, with age, premorbid verbal IQ, actual nonverbal IQ, CD4+ cell counts, HawaiiV-1 plasma viral burden, and duration of HIV seropositivity as independent variables. Results are given in Table 4. There was no correlation between both tests and the markers of the immune status. Neither the contraction time nor the MRAM showed significant correlation with duration of HIV seropositivity, and no consistent correlation with premorbid or actual intelligence or age was observed. HIV Dementia Scale scores (both sum score and time dependent subscores) showed a consistent and highly significant correlation to premorbid and actual intelligence and, less markedly, to age and duration of HIV seropositivity.
DISCUSSION
The clinical manifestation of HIV-associated dementia carries a poor prognosis for the individual HIV-positive patient.4,5,16 However, if detected early in the course of the disease, it may be amenable to antiretroviral therapy.16–21 Effective screening for and adequate quantification of HIV-associated psychomotor slowing are therefore essential to patients, treating physicians, and researching scientists. The ideal screening tool should not be expensive; it should be universally available (ideally bedside), brief, sensitive and reliable in detecting “subcortical” dementia, and it should allow for the selection of patients for more extensive neuropsychological/electrophysiological testing and clinical trials. The HDS was explicitly designed to fulfill these criteria and has proved to be a beneficial screening tool.2 Human immunodeficiency virus associated dementia is considered a subcortical dementia,22–24 and its neuropathology focuses on the basal ganglia.23–31 As the basal ganglia play a pivotal role in movement control,32 the HDS emphasizes motor skills and timed tasks. Psychomotor speed is assessed with the timed, written alphabet and represents the most important subscore (6 out of 16 points). The construction task (cube copy time) is also a timed task and scores the time needed to correctly copy the cube (another 2 points). Timed motor tasks thus account for 50% of the HDS sum score. With this design, the HDS actually screens for psychomotor slowing. Accordingly, we observed highly significant differences between patients scoring >10 and ≤10 in the HDS for both contraction time and MRAM (Table 2). These parameters have been shown to sensitively describe psychomotor slowing in HIV-positive clinically yet unaffected patients.8 Analysis revealed significant correlations between contraction time and MRAM on one hand and HDS sum score and HDS subscores for psychomotor speed and construction on the other hand (both timed tasks) (Table 3). Memory and attention do not correlate with contraction time or MRAM. In our population, HDS defines approximately 20% of patients as mildly demented or at risk for HIV dementia. This percentage is comparable to the percentage that we observed in a long-term survey,20 where the prevalence of pathological contraction time ranged between 12% and 16% for the years since introduction of highly active antiretroviral therapy (HAART) in 1996. In the original study population, the HDS score was relatively independent of age and education. In our patients, we found significant differences between patient groups for age, premorbid verbal intelligence quotient (IQ), and actual nonverbal IQ. We also observed significant correlations between the HDS sum score and the subscores for psychomotor speed and construction and for the premorbid verbal and actual nonverbal IQ (Table 4), which were less marked for age and duration of HIV-seropositivity. These correlations reflect the influence of intelligence on a dementia scale. This is obvious for the premorbid verbal intelligence and a subtest evaluating the written alphabet, as it is for the actual nonverbal intelligence and a dementia scale. In the original HDS, the authors stated accordingly, “The HDS may be insensitive to mild HIV dementia in highly educated patients.” Thus, a possible interference has not been excluded. In our cohort, electrophysiological motor testing, as quantified by MRAM and contraction time, was almost completely independent of both premorbid and actual intelligence. This finding is in contrast to other studies33 and probably reflects that this test battery focuses on motor performance. In this study, we show that electrophysiological motor testing is not influenced by premorbid or actual intelligence, and, in earlier studies, we have demonstrated that it is not influenced by intravenous drug use,34 concomitant depression,35 or peripheral nerve damage.36 Compared to the HDS, this test battery is a simple continuous measure that cannot serve as a simple screening tool for reasons of equipment. However, as a more quantitative method, it is useful in monitoring the course of dementia as well as deterioration and response to antiretroviral therapy.15,17,21 Furthermore, as it is less subject to potentially interfering factors (see above), electrophysiological motor testing is useful in studies on HIV neuropathogenesis, with a special focus on basal ganglia dysfunction30,31 In fact, electrophysiological motor testing cannot and should not replace a complete neuropsychological assessment that necessarily covers skills in a variety of domains that are involved in HIV dementia. In conclusion, we view the domain of neuropsychological testing in the description of all deficits observed, the domain of the HDS in rapid screening for psychomotor slowing, and the domain of electrophysiological motor testing as a scientific tool to quantify one pivotal deficit in HIV neuropathogenesis: basal ganglia mediated psychomotor slowing.
References
1.
Janssen RS, Cornblath DR, Epstein LG, et al: Nomenclature and research case definitions for neurologic manifestations of human immunodeficiency virus-type 1 (HIV-1) infection. Neurology 1991; 41:778–785
2.
Power C, Selnes OA, Grim JA, et al: HIV dementia scale: a rapid screening test. J Acquir Immune Defic Syndr Hum Retrovirol 1995; 8:273–278
3.
Dougherty RH, Skolasky RL Jr, McArthur JC: Progression of HIV-associated dementia treated with HAART. AIDS Read 2002; 12:69–74
4.
Arendt G, Hefter H, Hilperath F, et al. Motor analysis predicts progression in HIV-associated brain disease. J Neurol Sci 1994; 123:180–185
5.
Sacktor NC, Bacellar H, Hoover DR, et al: Psychomotor slowing in HIV infection: a predictor of dementia, AIDS and death. J Neurovirol 1996; 2:404–410
6.
Grant I, Atkinson JH, Hesselink JR, et al: Evidence for early central nervous system involvement in the acquired immunodeficiency syndrome (AIDS) and other human immunodeficiency virus (HIV) infections. Ann Internal Med 1987; 107:826–836
7.
McArthur JC, Cohen BA, Selnes OA, et al: Low prevalence of neurological and neuropsychological abnormalities in otherwise healthy HIV-1-infected individuals: results from the multicenter AIDS cohort study. Ann Neurol 1989; 26:601–611
8.
Arendt G, Hefter H, Elsing C, et al: Motor dysfunction in HIV-infected patients without clinically detectable central-nervous deficit. J Neurol 1990; 237:362–368
9.
Hefter H, Hömberg V, Freund H-J: Quantitative analysis of voluntary and involuntary motor phenomena in Parkinson’s disease, in Early Diagnosis and Preventive Therapy in Parkinson’s Disease. Edited by Przuntek H, Riederer P. Wien, NY, Springer-Verlag, 1989, pp 65–73
10.
Hefter H, Arendt G, Stremmel W, et al: Motor impairment in Wilson’s disease, I: slowness of voluntary limb movements. Acta Neurol Scand 1993; 87:133–147
11.
Hefter H, Hömberg V, Lange HW, et al: Impairment of rapid movement in Huntington’s disease. Brain 1987; 110:585–612
12.
CDC: 1993 revised classification system for HIV infection and expanded surveillance case definition for AIDS among adolescents and adults. MMWR 1992; 41(RR-17):1–19
13.
Lehrl S, Triebig G, Fischer B: Multiple choice vocabulary test MWT as a valid and short test to estimate premorbid intelligence. Acta Neurol Scand 1995; 91:335–345
14.
Raven J: The raven’s progressive matrices: change and stability over culture and time. Cognit Psychol 2000; 41:1–48
15.
Arendt G, Hefter H, Buescher L, et al: Improvement of motor performance of HIV-positive patients under AZT therapy. Neurology 1992; 42:891–896
16.
Price RW, Yiannoutsos CT, Clifford DB, et al: Neurological outcomes in late HIV infection: adverse impact of neurological impairment on survival and protective effect of antiviral therapy: AIDS clinical trial group and neurological AIDS research consortium study team. AIDS 1999; 13:1677–1685
17.
Arendt G, von Giesen HJ, Hefter H, et al: Therapeutic effects of nucleoside analogues on psychomotor slowing in HIV infection. AIDS 2001; 15:493–500
18.
Sacktor NC, Lyles RH, Skolasky RL, et al: Combination antiretroviral therapy improves psychomotor speed performance in HIV-seropositive homosexual men. multicenter AIDS cohort study (MACS). Neurology 1999; 52:1640–1647
19.
Sacktor N, Tarwater PM, Skolasky RL, et al: CSF antiretroviral drug penetrance and the treatment of HIV-associated psychomotor slowing. Neurology 2001; 57:542–544
20.
von Giesen HJ, Hefter H, Jablonowski H, et al: HAART is neuroprophylactic in HIV-1 infection. J Acquir Immune Defic Syndr 2000; 23:380–385
21.
von Giesen HJ, Koller H, Theisen, et al: Therapeutic effects of nonnucleoside reverse transcriptase inhibitors on the central nervous system in HIV-1-infected patients. J Acquir Immune Defic Syndr 2002; 29:363–367
22.
Cummings JL, Benson DF: Subcortical dementia: review of an emerging concept. Arch Neurol 1984; 41:874–879
23.
Berger JR, Nath A: HIV dementia and the basal ganglia. Intervirology 1997; 40:122–131
24.
Berger JR, Arendt G: HIV dementia: the role of the basal ganglia and dopaminergic systems. J Psychopharmacol 2000; 14:214–221
25.
Aylward EH, Henderer JD, McArthur JC, et al: Reduced basal ganglia volume in HIV-1-associated dementia: results from quantitative neuroimaging. Neurology 1993; 43:2099–2104
26.
Berger JR, Nath A, Greenberg RN, et al: Cerebrovascular changes in the basal ganglia with HIV dementia. Neurology 2000; 54:921–926
27.
Chang L, Ernst T, Leonido-Yee M, et al: Highly active antiretroviral therapy reverses brain metabolite abnormalities in mild HIV dementia. Neurology 1999; 53:782–789
28.
Navia BA, Cho E-S, Petito CK, et al: The AIDS dementia complex, II: neuropathology. Ann Neurol 1986; 19:525–535
29.
Neuen-Jacob E, Arendt G, Wendtland B, et al: Frequency and topographical distribution of CD68-positive macrophages and HIV-1 core proteins in HIV-associated brain lesions. Clin Neuropathol 1993; 12:315–324
30.
von Giesen HJ, Antke C, Hefter H, et al: Potential time course of human immunodeficiency virus type 1-associated minor motor deficits: electrophysiologic and positron emission tomography findings. Arch Neurol 2000; 57:1601–1607
31.
von Giesen HJ, Wittsack HJ, Wenserski F, et al: Basal ganglia metabolite abnormalities in HIV-1 associated minor motor deficits. Arch Neurol 2001; 58:1281–1286
32.
Freund HJ, Hefter H: The role of basal ganglia in rhythmic movement, in Advances in Neurology, vol 60. Edited by Narabayashi H, Nagatsu T, Yanagisawa N, Mizuno Y. New York, Raven Press, 1993, pp 88–92
33.
Satz P, Morgenstern H, Miller EN, et al: Low education as a possible risk factor for cognitive abnormalities in HIV-1: findings from the multicenter AIDS cohort study (MACS). J Acquir Immune Defic Syndr 1993; 6:503–511
34.
von Giesen HJ, Hefter H, Roick H, et al: HIV-specific changes in the motor performance of HIV-positive intravenous drug abusers. J Neurol 1994; 242:20–25
35.
von Giesen HJ, Bäcker R, Hefter H, et al: Depression does not influence basal ganglia mediated psychomotor speed in HIV-1 infection. J Neuropsychiatry Clin Neurosci 2001; 31:88–94
36.
von Giesen HJ, Köller H, Hefter H, et al: Central and peripheral nervous system functions are independently disturbed in HIV-1 infected patients. J Neurol 2002; 249:754–758
Information & Authors
Information
Published In
History
Published online: 1 May 2005
Published in print: May 2005
Authors
Metrics & Citations
Metrics
Citations
Export Citations
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.
For more information or tips please see 'Downloading to a citation manager' in the Help menu.
View Options
View options
PDF/EPUB
View PDF/EPUBGet Access
Login options
Already a subscriber? Access your subscription through your login credentials or your institution for full access to this article.
Personal login Institutional Login Open Athens loginNot a subscriber?
PsychiatryOnline subscription options offer access to the DSM-5-TR® library, books, journals, CME, and patient resources. This all-in-one virtual library provides psychiatrists and mental health professionals with key resources for diagnosis, treatment, research, and professional development.
Need more help? PsychiatryOnline Customer Service may be reached by emailing [email protected] or by calling 800-368-5777 (in the U.S.) or 703-907-7322 (outside the U.S.).