(Stroke. 1995;26:2023-2026.)
© 1995 American Heart Association, Inc.
Articles |
From Cornell University Medical College at Burke Rehabilitation Hospital, White Plains, NY.
Correspondence to Alexander Dromerick, MD, Department of Neurology, Washington University School of Medicine, Campus Box 8111, 660 S Euclid St, St Louis, MO 63110. E-mail awd3034@bjcmail.carenet.org.
| Abstract |
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Methods We reviewed our records and found 41 patients who had a single ischemic hemispheric stroke, HHH deficits, and an available CT scan performed more than 24 hours after the onset of symptoms. CT scans were read independently and blindly by the authors. Lesions were initially categorized by arterial distribution on the basis of CT templates published by Kinkel. The numerous combinations of arterial branch vessel occlusions observed did not allow for statistical analyses because of the small number of subjects within each subgroup. Lesions were therefore classified as cortical (C), subcortical (S), or mixed (M).
Results There were no significant differences among the three anatomic groups for age, sex, interval after stroke, Mini-Mental Status Examination score, or admission Barthel Index score. Functional outcome measures did not differ significantly for the three groups: mean±SD discharge Barthel score (C, 64±31; S, 47±20; M, 57±21), length of stay ([days] C, 64±25; S, 77±24; M, 73±28), and frequency of nursing home placement (C, 4/8; S, 3/6; M, 2/16).
Conclusions For patients with HHH deficits, the anatomic location of the lesion (C versus S versus M) does not affect functional outcome.
Key Words: cerebrovascular disorders outcome rehabilitation tomography, x-ray computed
| Introduction |
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Syndromic classifications based on neurological impairments may hold more promise. The lacunar syndromes are generally thought to be compatible with good recovery; unfortunately, this impression is based more on anecdotes than on critical outcome studies. Only one study of these syndromes used a standardized outcome scale.4
Another syndromic approach is that of Reding and Potes,5 who propose an outcome-prediction schema for patients with hemiparesis after an initial unilateral ischemic hemispheric stroke. On the basis of presence or absence of hemiparesis, hemihypesthesia, and hemianopsia, stroke patients can be grouped to show statistically significant differences in both their final level of function and the time needed to reach maximal recovery. Patients with all three deficitshemiparesis, hemihypesthesia, and hemianopsia (HHH syndrome)have little likelihood of regaining independence but are able to reach a level of assisted care at which they can be safely managed by an aged spouse in their own home. The HHH syndrome is also associated with an increased risk of other stroke-related complications,6 including incontinence,7 the shoulder-hand pain syndrome,8 and thromboembolism.9 Outcome prediction within this group is particularly important because these patients are likely to have the longest rehabilitation stay with the lowest function at discharge.
We have observed that several anatomically different unilateral ischemic hemispheric lesions may cause the HHH syndrome. The HHH syndrome can occur after partial or complete middle cerebral artery distribution infarction. It may also occur with extensive subcortical infarction in the distribution of the lateral lenticulostriate vessels or with involvement of the anterior choroidal arterial distribution affecting the globus pallidus and posterior limb of the internal capsule. It is not yet known to what extent lesion location affects functional outcome for patients with HHH syndrome.
This study is a retrospective analysis of patients with HHH syndrome due to initial unilateral ischemic hemispheric stroke. We first define the spectrum of lesions seen on radiography that cause the HHH syndrome and then ask whether different stroke locations are associated with different functional outcomes for this group of patients.
| Subjects and Methods |
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Only patients with unilateral ischemic hemispheric infarction were included in this study. Patients without an available CT scan or with a CT scan performed less than 24 hours after stroke onset were excluded from analysis. Forty-one patients met the above criteria for study inclusion.
CT scans were read independently and blindly by the two authors, and results were compared. In cases of disagreement, the final interpretation was reached by consensus. The CT templates of Kinkel11 were used initially to define cortical arterial distributions. For outcome evaluation, the large combination of arterial branch occlusions observed made statistical analysis of small groups impractical. To define sample sizes adequate for analysis, a simplified classification schema was used. Cortical infarcts that involved subcortical white matter, but not the basal ganglia or internal capsule, were classified as "cortical." Infarcts were defined as "subcortical" if there was no visible cortical involvement and they involved the caudate nucleus, internal capsule, putamen, or globus pallidus. CT scans that showed no detectable infarcts were classified as subcortical. "Mixed" infarcts involved both cortical structures and the basal ganglia or internal capsule.
Self care and ambulation were scored using the Barthel Index and Barthel ambulation subscore.12 These assessments were made by rehabilitation staff who were unaware of the test hypothesis.
Data were analyzed using the Macintosh version of Statview512+
marketed by BrainPower Inc. Two-tailed, unpaired t tests
were performed on interval scale data. The Kruskal-Wallis test was used
for ordinal scale data. The
2 statistic or
Fisher's exact test was used as appropriate to assess categorical
data. All analyses were considered significant if the
probability statistic was
.05.13
| Results |
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Table 3
presents the results of the admission
neurological examination. No significant differences were found in the
Mini-Mental State Examination scores.14 Significant
differences were found in the motor scores of the proximal upper
extremity and both the proximal and distal lower extremity, suggesting
that if significant strength was found in these areas, the infarct was
likely to be purely cortical.
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Table 4
displays data on standard measures of
self-care function. On admission to the rehabilitation unit, all
patients were dependent on assistance for at least a portion of their
self care. Total Barthel Index scores and the Barthel walking subscores
were not statistically different among the three groups.
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Outcome measures are shown in Table 5
. Virtually all
patients remained at least partially dependent for function of
activities of daily living. Weak trends suggested that the purely
cortical patients do slightly better than the others, but these trends
did not reach statistical significance in this sample.
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Fig 1
is a life-table analysis of the
probability of recovering the ability to walk 150 ft with assistance.
Only two patients eventually ambulated 150 ft unassisted, one of whom
became independent with self care. Fig 2
is a
life-table recovery curve showing the probability of reaching a
Barthel score of 60, a point at which assisted home care becomes
practical.
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| Discussion |
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Our finding is consistent with previous neuroimaging-based classification systems in which clinical factors were more robust predictors of outcome than lesion location or size. Rascol et al15 studied the CT localization of pure motor strokes and incidentally commented on outcome. He reported that lateral lenticulostriate lesions were associated with "major sequelae" in three of four cases, whereas most patients with anterior choroidal or medial lenticulostriate lesions had "favorable" outcomes or "complete recovery." Other reports16 17 studied isolated subcortical strokes but did not focus on either functional recovery or the spectrum of associated neurological impairments produced.
Clinicoanatomic correlation is probably most advanced in the field of aphasiology. Comparisons of clinical syndromes with imaged lesions show that only finely detailed lesion mapping such as that done by Naeser et al18 has yielded useful information in predicting either the rate of recovery or the final level of language disability. These studies have emphasized the effect of subcortical lesion location on language recovery. No similar attempts at finely mapping subcortical motor pathways in humans have yet been published. Little information is available on humans concerning the variability of primary motor pathways within either the centrum semiovale or the internal capsule.
There are several reasons why CT lesion localization might not improve outcome prediction. Early CT scanning may not reflect the true extent of the lesion. The limitations of CT imaging are well known and include both overestimation and underestimation of lesion size, "fogging" of lesions subacutely, and relatively poor anatomic resolution.19 Additionally, a more refined anatomic analysis in a larger group of patients might yield more information.
No studies have evaluated MRI and stroke outcome prediction, but MRI does not always clearly distinguish ischemic tissue from early infarct.19 Diffusion-weighted MRI may hold some promise for early lesion definition. Preliminary data from MR spectroscopy of stroke lesions suggest that preservation of normal N-acetyl group levels and phosphocreatine-creatinine ratios is associated with better stroke recovery.20
This study using CT technology is a first step in melding clinical and neuroradiological information into a useful outcome prediction schema. It is unusual in that we have examined functional recovery for a group of patients with a single clinical syndrome using standard outcome measures. We have demonstrated that within the HHH syndrome there is little correlation between cortical, subcortical, or mixed lesion location and either neurological impairment or extent of functional recovery.
Received May 19, 1995; revision received July 18, 1995; accepted July 18, 1995.
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