Remote effects of caudate hemorrhage: a clinical and functional study

A Comparative Study of Regional Cerebral Blood Flow Asymmetry Index in Stroke Patients with or without Poststroke Depression Using 99m Tc-ECD Single-Photon Emission Computed Tomography

Introduction  Stroke is a major cause of death and disability around the globe. The development of depression following a stroke further increases the disability and impairs functional recovery. In recent decades, despite the advancement in structural and nuclear medicine imaging, the pathophysiologic basis of poststroke depression (PSD) is not well understood. Etiopathogenesis of PSD is multifactorial and afflictions of the frontal lobe, hippocampus, limbic region, and basal ganglia projections are implicated. Aim  The aim of this study was to assess the regional cerebral blood flow (rCBF) using 99m Tc-ethyl cysteinate dimer single-photon emission computed tomography (SPECT) in patients with (PSD + ) or without PSD (PSD-). Materials and Methods  To evaluate the hemispheric asymmetry, the percentage of asymmetry index (AI) was calculated for frontal, temporal, parietal, occipital, putamen, caudate, and thalamic regions of brain and compared between PSD+ and PSD-. The correlation between AIs over the different brain regions was also established in patients of PSD+ and PSD-. Our study cohort included 122 patients between 6 weeks and 1 year of stroke. Depression was present in 52 (42.6%) patients, assessed by hospital anxiety and depression scale (HADS) and general health questionnaire-28 items (GHQ-28) scale. The 28 patients with PSD+ and 18 PSD- gave consent for SPECT study. Results  Our results are based on 46 patients who underwent SPECT study. In patients with PSD+ and PSD-, the HADS and GHQ-28 scores were 8.93 ± 2.77 vs. 3.94 ± 2.15 ( p  = 0.001) and 40.96 ± 9.48 vs. 17.72 ± 5.38 ( p  = 0.001), respectively. A significant difference in rCBF AI was found in the temporal lobe ( p  = 0.03) between patients of PSD+ and PSD-. On logistic regression analysis, the odds ratio of rCBF AI for temporal lobe was 0.89 (95% confidence interval [CI]: 0.80-0.99; p  = 0.04) and caudate nucleus was 0.85 (95% CI: 0.73-0.98; p  = 0.03), which were statistically significant. PSD correlated with AI in temporal region ( r  = -0.03; p  = 0.03) but did not show significant correlation with other regions of brain between PSD+ and PSD-. Conclusion  The presence of temporal lobe rCBF AI on SPECT is significantly associated with PSD. This may reflect the dysfunction of the limbic system and contribute to the occurrence of PSD.

The role of the striatum in rule application: the model of Huntington's disease at early stage

The role of the basal ganglia, and more specifically of the striatum, in language is still debated. Recent studies have proposed that linguistic abilities involve two distinct types of processes: the retrieving of stored information, implicating temporal lobe areas, and the application of combinatorial rules, implicating fronto-striatal circuits. Studies of patients with focal lesions and neurodegenerative diseases have suggested a role for the striatum in morphological rule application, but functional imaging studies found that the left caudate was involved in syntactic processing and not morphological processing. In the present study, we tested the view that the basal ganglia are involved in rule application and not in lexical retrieving in a model of striatal dysfunction, namely Huntington's disease at early stages. We assessed the rule-lexicon dichotomy in the linguistic domain with morphology (conjugation of non-verbs and verbs) and syntax (sentence comprehension) and in a non-linguistic domain with arithmetic operations (subtraction and multiplication). Thirty Huntington's disease patients (15 at stage I and 15 at stage II) and 20 controls matched for their age and cultural level were included in this study. Huntington's disease patients were also assessed using the Unified Huntington's Disease Rating Scale (UHDRS) and MRI. We found that early Huntington's disease patients were impaired in rule application in the linguistic and non-linguistic domains (morphology, syntax and subtraction), whereas they were broadly spared with lexical processing. The pattern of performance was similar in patients at stage I and stage II, except that stage II patients were more impaired in all tasks assessing rules and had in addition a very slight impairment in the lexical condition of conjugation. Finally, syntactic rule abilities correlated with all markers of the disease evolution including bicaudate ratio and performance in executive function, whereas there was no correlation with arithmetic and morphological abilities. Together, this suggests that the striatum is involved in rule processing more than in lexical processing and that it extends to linguistic and non-linguistic domains. These results are discussed in terms of domain-specific versus domain-general processes of rule application.

Transient global amnesia in a patient with acute unilateral caudate nucleus ischemia

The pathogenesis and localization of neuronal dysfunction in transient global amnesia (TGA) is still disputed more than 40 years after the first description of this clinical entity. Previous studies have indicated that structural abnormality is rare in TGA. We report a case of TGA in a patient with acute ischemia in the body of right caudate nucleus. This provides evidence in support of an ischemic hypothesis as the possible etiology of TGA. The role of caudate nucleus in human memory is also reviewed.

The thalamus and basal ganglia: What is exactly where? A reply to 'Neuropsychological consequences of right thalamic injury: case study and review,' MJ Summers, Brain and Cognition 50 (2002)

The present paper re-analyzes anatomical and clinical data of a previous case report (Summer, 2002). In this case study, a patient with severe neuropsychological and behavioral impairments is described and it is claimed that these impairments are causally linked to an right thalamic lesion. A simple method how to perform a lesion analysis is introduced which shows that PD's lesion was a striatocapsular hematoma, and not a thalamic bleeding. The results of this anatomical re-analysis challenge the original behavioral-lesion hypothesis and emphasize the importance to provide appropriate data on brain lesions and clinical findings in neuropsychological case reports.

Cognitive and motor functioning in a patient with selective infarction of the left basal ganglia: evidence for decreased non-routine response selection and performance

Focal damage to the basal ganglia is relatively rare, and little is known about the cognitive effects of damage to specific basal ganglia structures. A 28-year-old, highly educated male (patient RI) sustained a unilateral left ischemic infarction involving primarily the putamen and secondarily the head of the caudate and the anterior internal capsule. Two detailed neuropsychological assessments, at 3 and 16 months post-infarction, revealed that a majority of cognitive abilities were spared. RI's general intelligence, simple attention, concept formation, cognitive flexibility, and explicit memory were unaffected. Select cognitive abilities were affected, and these appeared to be related to direct involvement of the putamen and/or to indirect disruption of circuits between the basal ganglia and frontal lobes. Consistent with involvement of the left putamen, RI showed micrographia with his right hand. Interestingly, his micrographia was context-dependent, appearing only when verbal expression was involved (e.g., present when writing spontaneously, but not when copying sentences or when drawing). Evidence of disruption to frontal systems included variably decreased sustained attention, mildly decreased ability to generate words and to generate ideas, and significantly impaired abstraction ability in both verbal and visual modalities. Although there are several possible interpretations for these findings, this pattern of cognitive and motor functioning is consistent with neuroimaging research suggesting that the frontal/subcortical circuit between the putamen and frontal motor areas plays a role in non-routine response selection and performance.

Acute caudate vascular lesions

BACKGROUND AND PURPOSE

We sought to evaluate demographic features, risk factors, clinical profiles, and behavioral abnormalities in patients with caudate lesion, either with infarct or with hemorrhage involving the caudate nucleus.

METHODS

We studied all patients with acute caudate stroke confirmed by CT or MRI who were admitted to our stroke unit over a 5-year period. A database containing risk factors, clinical features, type and mechanism of stroke, and caudate vascular territories was analyzed.

RESULTS

Thirty-one patients had acute caudate stroke (24 men and 7 women; mean age, 62.3 years). Caudate infarct was present in 25 patients and caudate hemorrhage in 6. The main risk factors for caudate infarct were hypertension (64%), hypercholesterolemia (32%), diabetes mellitus (28%), and previous myocardial infarct (20%). Hypertension was present in 4 patients (67%) with caudate hemorrhage, and arteriovenous malformation was present in 1 patient (17%). Small-artery disease was diagnosed in 14 patients (59%), cardiac embolism in 5 patients (20%), and large-artery disease in 2 patients (8%), and 2 patients (8%) had mixed etiology. The most frequent neurological abnormalities were abulia and psychic akinesia (48%), frontal system abnormalities (26%), speech deficits in patients with left-sided lesions (23%), and neglect syndromes in those with right-sided lesions (10%). Fifteen patients with caudate infarct (60%) and 3 patients with hemorrhage (50%) were able to return to normal daily life. Patients with infarct in the territory of the lateral lenticulostriate arteries extending to neighboring structures showed more frequent motor and neuropsychological deficits than those with infarct in the territory of the anterior lenticulostriate arteries.

CONCLUSIONS

The clinical presentation of patients with caudate hemorrhage mimicked subarachnoid hemorrhage with or without motor and neuropsychological signs. Caudate vascular lesions with concomitant neighboring structure involvement represent a specific stroke syndrome, usually caused by small-artery disease and in one fifth of the patients caused by cardiac embolism. The behavioral abnormalities were mostly due to medial, lateral, and ventral caudate subnuclei damage and coexisting lesion of the anterior limb of the internal capsule.

Selective speech motor, syntax and cognitive deficits associated with bilateral damage to the putamen and the head of the caudate nucleus: a case study

Deficits in speech production, sentence comprehension and abstract reasoning occurred in a subject having profound bilateral damage to the putamen and the caudate nucleus. Acoustic analyses indicated that the subject's speech was degraded due to inappropriate sequencing of articulatory gestures that involve different articulatory structures. Transitions between sounds were slow and often did not achieve target configurations. The subject had a 14% error rate comprehending distinctions in meaning conveyed by syntax in English sentences; normal controls make virtually no errors in this test. Cognitive deficits involving impaired sequencing occurred: the subject had a 70% error rate on the Odd Man Out test when making decisions within a single category. Cognitive perseveration occurred when the subject was asked to shift categories. In contrast, performance was within normal ranges in tests of lexical access and memory. The pattern of deficits provides evidence for basal ganglia involvement in the regulation of sequencing across modalities.

Subcortical aphasia

We critically review the literature on subcortical aphasia, suggest that a number of traditional concepts regarding mechanisms of aphasia are inconsistent with now abundant data, and propose several new hypotheses. The absence of aphasia in 17 reported cases of dominant hemisphere striatocapsular infarction and the finding of nearly every conceivable pattern of language impairment in 33 different reported cases of striatocapsular infarction provide strong evidence against a major direct role of the basal ganglia in language and against disconnection or diaschisis as mechanisms of nonthalamic subcortical aphasia. However, detailed consideration of the vascular events leading to striatocapsular infarction strongly suggests that associated linguistic deficits are predominantly related to sustained cortical hypoperfusion and infarction not visible on structural imaging studies. Thalamic disconnection, as may occur with striatocapsular infarcts with extension to the temporal stem and putamenal hemorrhages, may also contribute to the language deficits in some patients. Review of the literature on thalamic infarction, in conjunction with previously unreported anatomic details of four cases, suggests that what infarcts in the tuberothalamic artery territory and the occasional infarcts in the paramedian artery territory associated with aphasia have in common is damage to the frontal lobe-inferior thalamic peduncle-nucleus reticularis-center median system that may be involved in regulating the thalamic gate in attentional processes. Disruption of attentional gating in the pulvinar and lateral posterior nuclei resulting from such lesions may impair selection of specific neuronal networks in the projection field of these nuclei that serve as the substrate for lexical-semantic function, which is in effect a disruption of a type of working memory, as defined by Goldman-Rakic. We define this as a defect of selective engagement.

Long-term cognitive impairment associated with caudate stroke

BACKGROUND AND PURPOSE

Neuropsychiatric findings were examined in 91 patients with acute focal subcortical lesions to determine whether cognitive outcome would differ depending on whether the head of the caudate or other subcortical structures were injured.

METHODS

Patients were evaluated using the Mini-Mental State Examination (MMSE), Hamilton Rating Scale for Depression, and modified Present State Examination. Patients were reexamined at short-term (3 to 6 months) or long-term (1 to 2 years) follow-up.

RESULTS

There were no significant intergroup differences in the MMSE scores at the initial evaluation or at short-term follow-up. At long-term follow-up, however, patients with either right or left caudate lesions had significantly lower MMSE scores than patients with other subcortical lesions.

CONCLUSIONS

A significant number of patients with caudate infarction deteriorate in their intellectual function between 1 and 2 years after stroke. This phenomenon could be mediated through disruption of cortical projections to the caudate.

Acute frontal lobe syndrome and dyscontrol associated with bilateral caudate nucleus infarctions

BACKGROUND

A 67-year-old man presented with acute onset of spatial and temporal disorientation, memory loss and associated episodic dyscontrol. Investigations showed infarctions of both caudate nuclei. This patient presented a unique opportunity to study the relationship between the lesions, his behaviour, and neuropsychological testing.

METHOD

Single case report. Investigations included interviews to determine cognitive impairment, i.e. WAIS-R, MMSE, and neurological examination.

RESULTS

Extensive neuropsychological testing revealed severe impairment on tasks requiring planning, memory or abstract thought. These findings are very similar to those seen in Huntington's disease.

CONCLUSIONS

A neurobiological hypothesis is proposed to account for his symptoms, and recent discoveries in the basic sciences used to inform his management.

Subcortical aphasia: a specific clinical picture?

100 aphasic patients were examined with a scorable aphasia battery looking at the frequency of various aphasia types and the possible specificity of clinical pictures in deep-seated lesions. One month after onset, "atypical" aphasiological syndromes proved to be rare and to have the same frequency in patients with cortico-subcortical or capsulostriatal deep-seated lesions. In the latter condition, no specific clinical syndrome was brought out, although verbal comprehension disorders were usually less severe than in cortico-subcortical lesions.

Regional cerebral blood flow changes following chronic administration of antidepressant drugs

1. Twenty-six patients with major unipolar depression were rated clinically and regional cerebral blood flow (rCBF) determined prior to and after six months of treatment with 75-100 mg/day amitriptyline (n. 16) or 200 mg/day amineptine (n. 10). 2. rCBF was measured in 16 regions over each hemisphere by the Xenon 133 inhalation method and was computed as the initial slope index (ISI). The severity of depression was quantified by the Hamilton rating scale for depression. 3. Baseline rCBF values of depressed patients tended to be lower than those of normal subjects. Significant reductions were observed for all probes exploring the frontal region of the left hemisphere and for some probes exploring the frontal region of the right hemisphere. Chronic treatment with amitriptyline induced a significant increase in rCBF in the left frontal region. Similar results were obtained after treatment with amineptine. 4. Besides confirming frontal lobe dysfunction in depressed patients which is reversed by treatment with classic tricyclic antidepressants, the present results show that this dysfunction may also be reversed by treatment with dopaminergic drugs.

Contribution of diaschisis to the clinical deficit in human cerebral infarction

BACKGROUND AND PURPOSE

Regions of decreased cerebral blood flow are often seen on single-photon emission computed tomography (SPECT) after stroke and have been widely reported to add to the clinical deficit. However, such reports have not distinguished between correlation and causation. We analyzed 124 serial SPECT scans performed in 50 patients to assess the role of diaschisis in the clinical deficit after stroke.

METHODS

SPECT with the use of 99mTc-hexamethylpropyleneamine oxime (99mTc-HMPAO) was performed in a prospective, unselected series of 50 patients with cerebral infarcts studied at a median of 1.1, 6.8, and 95 days after ictus. Patients were also assessed with the use of the Canadian Neurological Scale, the Barthel Index, a neuropsychological evaluation, and infarct volume measurement.

RESULTS

One hundred twenty-four serial SPECT scans were done in 50 patients. Diaschisis was identified at 168 sites. There was insufficient correlation between diaschisis and the clinical measurements to support the suggestion that diaschisis independently causes clinical deficits beyond those due to the infarct itself. Unlike the clinical status, diaschisis showed little tendency to resolve during the 3-month follow-up period of the study. Several of the instances of correlation were shown to be of a noncausal kind, with both the diaschisis and the clinical deficit being due to the lesion directly; there was no known mechanism for the diaschisis to cause the clinical deficit.

CONCLUSIONS

Diaschisis does not independently add to the clinical deficit after stroke. It is more likely that it simply represents part of the damage done by the stroke.

Mesial temporal cortex hypoperfusion is associated with depression in subcortical stroke

BACKGROUND AND PURPOSE

This study was conducted to evaluate local cerebral blood flow changes in patients with depression after a subcortical stroke.

METHODS

Clinical and neuropsychological assessments were performed in 15 patients with a single subcortical lesion. Depression was assessed by DSM-III-R. In addition, the Hamilton Rating Scale for depression, the Zung Self-Rating Depression Scale, and the Beck scale were administered to each patient. Single-photon emission-computed tomography study was performed with 99mTc hexamethylpropyleneamine oxime.

RESULTS

In all patients cortical regions ipsilateral to subcortical lesions were significantly less perfused than the contralateral cortex. Cerebral blood flow values were significantly lower in depressed patients (n = 8) than in nondepressed patients (n = 7) only in the mesial temporal cortex of the affected hemisphere. Cerebral blood flow values in the mesial temporal cortex of the affected hemisphere significantly correlated with the severity of depression.

CONCLUSIONS

Temporal lobe hypoperfusion may reflect a dysfunction of the limbic system, suggesting that this location may be critical for the occurrence of depressive symptoms in patients with subcortical stroke.

Choreo-acanthocytosis like phenotype without acanthocytes: clinicopathological case report. A contribution to the knowledge of the functional pathology of the caudate nucleus

Detailed clinical and neuropathological findings in two unrelated patients with a chorea-acanthocytosis-like phenotype (CA) are reported. One case met all the diagnostic criteria of CA and had a deceased brother with the same disease. The second case had a virtually identical phenotype to the former but without acanthocytes. These findings suggest that both patients are affected by the same disease and that acanthocytes are not essential to the diagnosis. Neuropathological autopsy studies on the brain of the second case showed selective atrophy of the caudate nucleus that seemed to correspond to the movement disorder and behavioural abnormalities prominent in this patient. In both subjects, morphometric and ultrastructural examination of the peripheral nerve showed loss of myelinated fibres, more accentuated distally, and cytoskeletal changes in the axoplasm. These findings support the hypothesis that peripheral neuropathy in CA is caused by distal axonopathy.

Pure topographical disorientation due to a deep-seated lesion with cortical remote effects

Lesions producing pure topographical disorientation syndromes are classically located either in the right parietal region either in the right parahippocampal gyrus. The patient described in the present study was admitted to hospital after sudden onset of a left hemiparesis. The lesion at CT scan was located in the posterior limb of the right internal capsule. Neuropsychological assessment was normal except for the presence of a major topographical disorientation and of mnestic disturbances for visuo-spatial material leading us to attribute topographical disorientation to a specific loss of topographical memory. Regional cerebral blood flow measurements disclosed a right parietal hypoperfusion. This remote cortical effect could account for the presence of the neuropsychological disorders.

Movement disorders and psychological tests of frontal lobe function in schizophrenic patients

Neuropsychological tests of frontal lobe functions were undertaken in 46 chronic schizophrenic patients who were also rated for movement disorders. Tardive dyskinesia was found to have significant associations with most of these psychological tests. The possible mechanisms are discussed within the context of known neostriatal psychological functions.

Remote cortical dysfunction in aphasic stroke patients

We studied the effect of deep-seated left hemispheric lesions on cortical blood flow in 18 right-handed aphasic stroke patients. Regional cerebral blood flow was measured at rest and during the performance of a functional naming test using the two-dimensional xenon-133 inhalation method. Compared with 10 controls, at rest the patients showed regional cortical hypoperfusion in the left frontoparietal region. In the controls, activation patterns from the rest to the test condition involved mainly the left hemisphere areas. In the patients, a lack of blood flow change was observed in several areas that were usually hypoperfused at rest. However, in patients with slight verbal expression disorders there were obvious blood flow increases in other brain regions in both hemispheres. Such cortical functional reorganization and the presence of a remote cortical dysfunction could play a role in the pathophysiology of language disorders.

Manic-depressive and pure manic states after brain lesions

Although mania is a rare complication of brain lesions, recent reports have emphasized the importance of lesion location and genetic predisposition in these patients. In the present study we compared patients who developed a bipolar affective disorder (i.e., mania and depression) after a brain lesion with patients who only developed mania. Although no significant between-group differences were found on demographic variables, the manic-depressed group showed significantly more impairments on the Mini Mental State Exam than the mania only group. All the bipolar patients had subcortical lesions (mainly right head of the caudate and right thalamus), while patients with unipolar mania had significantly higher frequency of cortical involvement (mainly right orbitofrontal and basotemporal cortices). It is suggested that subcortical and cortical right hemisphere lesions may produce different neurochemical and/or remote metabolic brain changes that may underlie the production of either a bipolar disease or a unipolar mania.

Local as well as remote functional and metabolic changes after focal ischemia in cats

Behavior and limb placing ability were analyzed acutely and subacutely (up to 21 days) following unilateral occlusion of the middle cerebral artery (MCA) in cats. Immediately following occlusion, all tested cats started to display a sequence of different behaviors, characteristic for 1) an ipsilateral inhibition of dopaminergic activity in the caudate nucleus (CN); 2) an inhibition of GABAergic activity in the reticular substantia nigra (SNR); 3) a stimulation of GABA receptors in the deeper layers of the colliculus superior (CSDL) (starting-time of these phases: about 4, 12 and 25 min, respectively). The latter behavior was also present subacutely. In addition, unilateral orofacial dyskinetic movements were observed acutely as well as subacutely. Contralateral limb placing was deficient in all cats 60 min postocclusion; it was at least partly restored subacutely. Twenty-one days after the occlusion, [14C]-2-D-deoxyglucose uptake was relatively reduced in the ipsilateral CN (especially in its posterior part), the ipsilateral SNR and the ipsilateral CSDL. The anterior CN appeared to be less affected than the posterior CN. Metabolism was relatively reduced in the sensorimotor cortex only in part of the tested cats. The data show that unilateral MCA occlusion produces consistent functional changes in all structures studied apart from the sensorimotor cortex, viz. the CN, the SNR and the CSDL.

Diencephalic amnesia: a reorientation towards tracts?

The principal thalamic and hypothalamic structures implicated in mnemonic information processing are the mediodorsal nucleus of the thalamus, the pulvinar, anterior thalamus, and laterodorsal nucleus, the mamillary body, and the mamillothalamic tract and internal medullary lamina. Determining the contribution of an individual region in memory is quite difficult as it is nearly impossible to find a circumscribed damage of only one region. On the contrary, some illnesses affecting primarily the diencephalon, such as Korsakoff's disease, tend to involve several structures together. Furthermore, even when cases with similar circumscribed diencephalic damage can be found, these will not necessarily demonstrate the same outcome on the behavioral level. Therefore, the role or contribution of individual memory-related diencephalic structures has to be inferred by comparing a number of cases and by then extracting distinct features common to a given group. Such an approach revealed that the contributions of the two fiber systems mentioned above, mamillothalamic tract and internal medullary lamina, might be more important in processing information long-term than had been acknowledged previously and might be more important than that of the nuclear masses mentioned, especially of the mediodorsal thalamus. This outcome underlines the view that emphasizing interactions between brain regions rather than single static masses will provide a more realistic picture of how the nervous system acts in information processing.

Remote effects of subcortical cerebrovascular lesions: a SPECT cerebral perfusion study

The remote effects of small unilateral cerebrovascular lesions confined to subcortical structures were evaluated by single photon emission computerized tomography (SPECT) and a CBF tracer, I-123 HIPDM. A CBF study was performed in 34 patients presenting with subcortical stroke either in the acute or in the chronic stages. Twenty-one of the 34 patients showed areas of cortical hypoperfusion ipsilateral to the subcortical lesion. In 14 patients, asymmetry of perfusion was also observed at the cerebellar level, perfusion being significantly reduced in the cerebellar hemisphere contralateral to the lesion. There was no correlation between the degree and extension of these remote effects and the type of stroke (ischemic or hemorrhagic), the patency of cerebral arteries, or the size and site of the lesion by transmissive computerized tomography (TCT). Subcortical hematomas showed a correlation between occurrence of remote effects and time interval from the onset of stroke, occurring more frequently in the acute phase. A correlation was observed between cortical and cerebellar remote effects and the severity of clinical presentation. The causes of remote effects are still unclear and have been extensively debated. Our data indicate that there is a relationship of remote effect to the neurological status. It is possible to show, by noninvasive, low-cost methods, remote CBF effects after stroke that may contribute to the assessment of brain functional impairment.