FYI

[Guest guest]

To All,

FYI. Though this study talks about Cronic Fatuge S yndrome, MS and

depression I think it has application to Cronic Lyme.

Larry NV

Neuropsychological Function in Patients With Chronic Fatigue Syndrome,

Multiple Sclerosis, and Depression

Ella Daly Department of Psychiatry, Massachusetts General Hospital,

ton, Massachusetts, USA; L. Komaroff Department of Medicine,

Brigham & Women's Hospital, Harvard Medical School, Boston, Massachusetts,

USA; Kerry Bloomingdale Department of Psychiatry, Beth Israel Deaconess

Medical Center, Boston, Massachusetts, USA; Department of

Psychiatry, Massachusetts General Hospital, ton, Massachusetts, USA;

Marilyn S. Albert Departments of Psychiatry and Neurology, Massachusetts

General Hospital, ton, Massachusetts, USA

[Applied Neuropsychology 8(1):12-22, 2001. © 2001 Lawrence Erlbaum

Associates, Inc.]

Abstract

Patients with chronic fatigue syndrome (CFS), multiple sclerosis (MS), and

major depression were compared with controls and with each other on a

neuropsychological battery that included standard neuropsychological tests

and a computerized set of tasks that spanned the same areas of ability. A

total of 101 participants were examined, including 29 participants with CFS,

24 with MS, 23 with major depressive disorder, and 25 healthy controls.

There were significant differences among the groups in 3 out of 5 cognitive

domains: memory, language, and spatial ability. Assessment of psychiatric

symptoms indicated that all 3 patient groups had a higher prevalence of

depression than the controls. A total measure of psychiatric symptomatology

also differentiated the patients from the controls. After covarying the

cognitive test scores by a measure of depression, the patient groups

continued to differ from controls primarily in the area of memory. The

findings support the view that the cognitive deficits found in CFS cannot be

attributed solely to the presence of depressive symptomatology in the

patients.

Discussion

These findings indicate that cognitive deficits are found in CFS patients

and MS patients, but they are mild in comparison to those seen in

depression. When the three patient groups are compared, the depression

patients have the greatest overall level of impairment. The MS patients

appeared to be slightly more impaired than the CFS patients, particularly

with respect to the summed IR, but this difference was not significant. In

addition, the depression patients had evidence of a different pattern of

impairment across the five cognitive domains than either the CFS or MS

patients.

Although the CFS patients were only mildly impaired in comparison to the

depression patients, there was evidence of impairment in comparison to

controls. The CFS group was impaired on all four of the memory tasks

compared to controls, including the nonverbal Pattern Recognition task. On

one of the memory tasks, the MQ of the WMS, both the depression group and

the MS group were significantly more impaired than the CFS patients. In

addition, compared to the control participants, CFS patients were impaired

on one of the language tasks (category fluency for animals), suggesting

difficulties with both language skills and planning and organizational

abilities related to executive function.

These findings also clearly demonstrate that MS produces cognitive

impairments. In agreement with numerous other studies, cognitive impairments

were primarily found in the memory domain (Beatty & Monson 1991a, 1991b,

1994; Brassington & Marsh, 1998; D'Esposito et al., 1996; Diamond, DeLuca,

Kim, & Kelley, 1997; Grafman, Rao, Bernardin, & Leo, 1991; Litvan & Grafman,

1988; Minden & Schiffer, 1990; Penman, 1991; Rao, 1995). Impaired memory

function has, in fact, been reported in 40% to 60% of patients (Rao et al.,

1993).

ThesummedIR, whichevaluated performance across all cognitive domains,

suggested that the MS patients were slightly more impaired than the CFS

patients, although this difference did not reach statistical significance.

Previous studies that havecomparedpatients with CFS and MS have found

differences in the level of impairment between the groups (e.g., DeLuca et

al., 1995; Krupp et al., 1994), although this finding has not been uniformly

reported (e.g., DeLuca et al., 1993).

The depression patients, as previously mentioned, were impaired over a broad

range of cognitive domains compared to the other two patient groups and had

evidence of impairment in all five cognitive domains when compared to

controls. Most of these differences remained after adjustment for degree of

depressive symptomatology. In addition, the summed IR demonstrated that the

depression patients were significantly more impaired overall, compared to

CFS patients and to the controls, but they were not significantly different

from the MS group.

These findings are in agreement with many studies demonstrating that

patients with depression can have substantial cognitive impairments (Byrne,

1977; Channon, Baker, & on, 1993; Cornblatt, Lenzenweger, &

Erlennmeyer-Kimmling, 1989; Elliot et al., 1996; Goodwin, 1997; Hertel &

Rude, 1991; Lemelin & Baruch, 1998; Mialet, Pope, & Yurgelun-Todd, 1996;

Paradiso, Lamberty, Garvey, & , 1997). In addition, many reports

indicate that cognitive impairment persists in participants with depression

even when their depression has remitted or levels of depression have been

covaried (Abas, Sahakian, & Levy, 1990; Ferrier et al., 1991; Paradiso et

al., 1997; Trichard et al., 1995).

Our findings are, however, at variance with several previous reports in

which patients with DEP were compared to CFS patients (DeLuca et al., 1995;

Marshall et al., 1997; Schmaling et al., 1994; Vollmer-Conna et al., 1997).

In these latter studies, the CFS patients were reported to be impaired to

approximately the same degree as the patients with depression.

One possible reason for the discrepancy between these previous studies and

our study is that the patient groups examined may have differed in terms of

severity of illness. In particular, the depression patients in this study

were more depressed in comparison to those used in several previous reports.

All of the participants in this study had either a diagnosis of major

depressive disorder or bipolar disorder (depressive type), and the majority

(19 of 23) were on antidepressant medication. In contrast, in previous

studies comparing CFS and depression patients, the patients with depression

were reported to have had either a diagnosis of dysthmia or depression, and

only a minority were on antidepressant medication (DeLuca et al., 1995;

Marshall et al., 1997; Schmaling et al., 1994).

Likewise, in the one previous study comparing the three patient groups

examined here, patients with CFS had symptoms of " moderate " severity and

presented with cognitive complaints (DeLuca et al., 1995). The MS group in

that study was specifically chosen to contrast patients with " mild " physical

symptoms with patients with CFS, based on a specific cutoff on the Expanded

Disability Status Scale (Kurtzke, 1983). In contrast, whereas we used

similar research criteria to define the CFS and MS groups in our study, we

did not select participants on the basis of the severity of physical

disability or the presence of cognitive complaints. Moreover, numerous

studies have demonstrated that the presence of cognitive impairments in MS

can be unrelated to the physical disability measured by the Expanded

Disability Status Scale (e.g., Rao, Leo, Bernardin, & Unverzagt, 1991). It

therefore seems likely that our study included a more clinically

heterogeneous group of participants with CFS and MS.

There has been much discussion about the role that psychiatric

symptomatology plays in the cognitive deficits observed in the patient

groups. We assessed a broad range of psychiatric symptomatology in this

study but found that the most consistent difference between the patient

groups and the controls was the presence of depressive symptomatology. We

therefore adjusted neuropsychological test scores for levels of depression.

Our results support the view that the presence of depression cannot solely

account for the cognitive differences among the patient groups or between

the patient groups and the controls.

In summary, our findings support the view that the cognitive deficits found

in CFS cannot be attributed solely to the presence of depressive

symptomatology in the patients. They are, for example, consistent with

reports of brain alterations in CFS patients (e.g., Lange et al., 1999).

Although the cognitive deficits of CFS patients appear somewhat similar to

those of patients with MS, there was a trend in this study for the MS

patients to be slightly more impaired. In addition, patients with depression

were clearly more impaired than either of the other patient groups. These

findings suggest that the degree of cognitive impairment observed in CFS,

MS, and depression is highly dependent on the criteria used to select the

patients. Among a heterogeneous sample of CFS and MS patients, cognitive

impairments will be present, but relatively mild in nature. The cognitive

impairments seen among patients with depression appear, however, to vary

greatly, depending on the severity of illness in the patients. Moreover,

even after adjusting for level of depression, differences in degree of

cognitive impairment among the groups are relatively unchanged. This

suggests that the underlying causes of cognitive deficits in CFS, MS and

depression vary.