Functional Brain Imaging with Cerebral Perfusion Spect in Cerebrovascular Disease, Epilepsy, and Trauma

Preoperatively reduced cerebrovascular contractile reactivity to hypocapnia by hyperventilation is associated with cerebral hyperperfusion syndrome after arterial bypass surgery for adult patients with cerebral misery perfusion due to ischemic moyamoya disease

The present study examined whether preoperatively reduced cerebrovascular contractile reactivity to hypocapnia by hyperventilation is associated with development of cerebral hyperperfusion syndrome after arterial bypass surgery for adult patients with cerebral misery perfusion due to ischemic moyamoya disease. Among 65 adult patients with ischemic moyamoya disease, 19 had misery perfusion in the precentral region on preoperative ¹⁵O positron emission tomography and underwent arterial bypass surgery for that region. Brain technetium-99 m-labeled ethyl cysteinate dimer single-photon emission computed tomography (SPECT) was preoperatively performed with and without hyperventilation challenge and relative cerebrovascular contractile reactivity to hypocapnia (RCVCR_hypocap) (%/mmHg) was calculated in the precentral region. Development of cerebral hyperperfusion syndrome was determined using perioperative changes of symptoms and brain N-isopropyl-p-[¹²³I]-iodoamphetamine SPECT performed after surgery. RCVCR_hypocap was significantly lower in the 6 patients with cerebral hyperperfusion syndrome (-2.85 ± 1.10%/mmHg) than in the 13 patients without cerebral hyperperfusion syndrome (0.18 ± 1.97%/mmHg; p = 0.0050). Multivariate analysis demonstrated low RCVCR_hypocap as an independent predictor of cerebral hyperperfusion syndrome (95% confidence interval, 0.04-0.96; p = 0.0433). Preoperatively reduced cerebrovascular contractile reactivity to hypocapnia by hyperventilation is associated with development of cerebral hyperperfusion syndrome after arterial bypass surgery for adult patients with cerebral misery perfusion due to ischemic moyamoya disease.

Elevated substance P (NK-1) receptor immunoreactivity in the cerebellum of seizure prone gerbil

In the present study, we performed a comparative analysis of the distribution of substance P (SP) receptor (NK-1) immunoreactivity in order to determine the characteristics of the SP system in the cerebelli of rat and gerbils. In the rat cerebellar cortex, only a few Purkinje cells exhibited weak NK-1 receptor immunoreactivity. Similar to the case of rat, NK-1 receptor immunoreactivity in the cerebellar cortex of seizure resistant (SR) gerbils was rarely detected. In contrast, in the cerebellar cortex of seizure sensitive (SS) gerbils, dendrites and cell bodies of Purkinje cell showed strong NK-1 receptor immunoreactivity. Similar to the cerebellar cortex, little NK-1 receptor immunoreactivity in deep cerebellar nuclei was observed in the rat. In SR gerbils, however, deep cerebellar nuclei showed weak NK-1 receptor immunoreactivity. NK-1 receptor immunoreactivity in the deep cerebellar nuclei of SS gerbils was markedly increased, as compared with SR gerbils. Based on the present data, we suggest that the SP system of cerebellar circuit in gerbil are different from rat, and over-expression of NK-1 receptor immunoreactivity in Purkinje cells of SS gerbils may be relevant to Purkinje cell loss induced by seizure activity.

Single photon emission CT and positron emission tomography in the evaluation of neurologic disease

Widely available SPECT allows imaging of certain critical components of neurotransmission, providing clinically and experimentally significant information. Future efforts may be directed toward developing innovative techniques to delineate dynamic neurochemical changes in vivo.

Neuropsychological test performance prior to and following sports-related mild traumatic brain injury

OBJECTIVE

To examine the utility of neuropsychological tests in assessing college athletes prior to and following a sports-related mild Traumatic Brain Injury (mTBI).

DESIGN

A prospective study of college athletes who sustained mTBI while engaged in sport. Preinjury baseline neuropsychological test data were obtained for athletes at risk for mTBI. Following an mTBI, the athlete and his or her matched noninjured control were evaluated at 2 hours, 48 hours, 1 week, and I month postinjury.

SETTING

Male and female athletes from a Division I college.

PARTICIPANTS

Male and female athletes from the football, men's ice hockey, men's and women's soccer, and men's and women's basketball teams at Penn State University. A total of 29 injured and 20 noninjured athletes participated in the study.

INTERVENTIONS

Neuropsychological test batteries were administered at baseline and serially following mTBI.

MAIN OUTCOME MEASURES

Post-Concussion Symptom Checklist, Hopkins Verbal Learning Test, Symbol Digit Modalities Test, Stroop Color-Word Test, Trail Making Test, VIGIL/W, List Learning, Digit Span, Penn State Cancellation Test, and Controlled Oral Word Association.

RESULTS

Neuropsychological test data yielded significant differences between injured athletes and controls at 2 hours and 48 hours following cerebral concussion; injured athletes performing significantly worse than controls. Injured athletes reported a significantly greater number of postconcussion symptoms 2 hours following injury but not at the 48-hour assessment. No multivariate group differences were found at 1 week, but univariate analyses suggested significant differences on a few measures. At 1 month postinjury, a statistically significant difference was found on one measure with injured athletes marginally outperforming controls.

CONCLUSIONS

Neuropsychological tests are useful in the detection of cognitive impairment following mTBI. The test data appear to be more effective than subjective report of symptoms in differentiating between injured and noninjured athletes at 48 hours postinjury. Although significant individual variability existed, most injured athletes recovered within 1 week of injury. A battery of tests, rather than any single test, is necessary to capture the variability that exists among injured athletes.