Tryggve Lundar

Persistent Cognitive Dysfunction Secondary to Cerebellar Injury in Patients Treated for Posterior Fossa Tumors in Childhood

Traditionally, the cerebral hemispheres have been regarded as the region of the brain responsible for cognitive functions, while the cerebellum has been considered to be primarily involved in motor functions. Recent studies focus also on the possible involvement of the cerebellum in neurocognitive functions. The aim of this study was to determine the neuropsychological profile of young adults treated for a posterior fossa tumor in childhood and look for possible support for the presence of the so-called ‘cerebellar cognitive affective syndrome’ in these patients. Two groups of young adults were studied. The astrocytoma group (n = 12) had been treated for a low-grade cerebellar astrocytoma with surgery alone (mean age at surgery was 8.6 years and mean age at neuropsychological testing was 23.5 years). The medulloblastoma group (n = 11) had been treated with surgery followed by radiotherapy and chemotherapy (mean age at surgery was 6.1 years and mean age at neuropsychological testing was 23.1 years). The neuropsychological test battery comprised measures of intelligence, motor function, attention, psychomotor speed, verbal memory and visual memory. The medulloblastoma group performed poorer than the astocytoma group on all neuropsychological measures except one. Nonetheless, the astrocytoma group also had impaired scores compared with standard norms on measures of motor speed, attention and executive function. No significant correlation between age at time of treatment and grade of neuropsychological impairment was found in the astrocytoma group, though there was a tendency that young age at time of treatment correlated with better outcome on IQ measures. In the medulloblastoma group, age was significantly correlated with outcome, for both IQ and degree of neuropsychological impairment. For this group, young age at time of treatment indicated a worse outcome. Conclusions: Persistent cognitive dysfunction was detected in patients treated for posterior fossa medulloblastoma and cerebellar astrocytoma. The astrocytoma group was treated with surgery alone, indicating that a cerebellar lesion can result in cognitive dysfunction. Thus, this study gives support to the existence of the cerebellar cognitive affective syndrome. Follow-up of all patients treated for posterior fossa tumor in childhood should include an extensive neuropsychological testing at regular intervals. This may be of benefit for school planning and later work planning.

Cerebral perfusion during nonpulsatile cardiopulmonary bypass

The recording of middle cerebral artery (MCA) flow velocity by the transcranial Doppler method offers a new, noninvasive, continuous technique for studies of cerebral circulation. Comparative studies of electromagnetic internal carotid artery (ICA) flowmetry and MCA flow velocity by the transcranial Doppler technique have demonstrated that observed changes in MCA flow velocities reflect concomitant changes in cerebral circulation. Eleven high-risk patients undergoing cardiopulmonary bypass (CPB) procedures were included in a pilot study. Arterial blood pressure (BP), central venous pressure, and epidural intracranial pressure (EDP) were recorded during CPB. Cerebral electrical activity was recorded by a cerebral function monitor. Flow velocity in the MCA was increased during nonpulsatile CPB in 10 of the 11 patients. This increase was related to the degree of hemodilution, and the flow velocity during steady-state CPB was 80 to 300% of the prebypass value. The MCA flow velocity changed, however, in a pressure-passive manner with the cerebral perfusion pressure (CPP = BP - EDP) in the individual patient, which indicates that cerebral autoregulation was not operative. During the first 15 minutes after termination of bypass, the MCA flow velocity was reduced, but remained higher than the prebypass level, 110 to 210% of the level during the last 5 minutes preceding CPB.

Dissociation between cerebral autoregulation and carbon dioxide reactivity during nonpulsatile cardiopulmonary bypass

Five patients undergoing cardiopulmonary bypass (CPB) procedures were extensively monitored because of anticipated high risk for neurological complications. Arterial blood pressure (BP), central venous pressure, and epidural intracranial pressure (EDP) were continuously recorded throughout CPB; thus, information on the cerebral perfusion pressure (CPP) was also continuously available (CPP = BP - EDP). Cerebral electrical activity was recorded by a cerebral function monitor. The flow velocity in the middle cerebral artery (MCA) was recorded using a transcranial Doppler technique. During steady-state CPB (constant hematocrit, constant temperature, and constant flow from the heart-lung machine) partial pressure of arterial carbon dioxide (PaCO2) was repeatedly changed to study the effect of changes in this variable on MCA flow velocity during nonpulsatile bypass. During CPB with constant temperature, hematocrit, and PaCO2, the effect of changes in CPP on MCA flow velocity was recorded and analyzed. During nonpulsatile, moderately hypothermic (28 degrees to 32 degrees C), low-flow (1.5 L/min/m2) CPB, there was no evidence of cerebral autoregulation, with CPP levels ranging from 20 to 60 mm Hg. The CO2 reactivity, however, was clearly present and in the range of 1.9 to 4.1%/mm Hg, indicating that there was a dissociation between cerebral autoregulation and CO2 reactivity under these circumstances.

Cognitive outcome after aneurysmal subarachnoid hemorrhage : Time course of recovery and relationship to clinical, radiological, and management parameters

OBJECTIVEAlthough many patients show a satisfactory physical outcome after aneurysmal subarachnoid hemorrhage (SAH), disabling cognitive dysfunction may still be present. This study focuses on the time course of cognitive recovery during the first year after aneurysmal SAH, and relates the neuropsychological test results to clinical, radiological, and management parameters. METHODSThirty-two patients were followed prospectively with neuropsychological examinations at 3, 6, and 12 months after SAH. Test results were compared with clinical entry variables, management variables, and pre- and postoperative radiological findings. RESULTSThe time course of cognitive recovery after aneurysmal SAH is heterogeneous, with motor and psychomotor functions recovering within the first 6 months, whereas verbal memory did not improve significantly until at least 6 months after the ictus. Clinical and radiological parameters reflecting the impact of the bleed were related to memory function, intelligence, and aphasia. The site of aneurysm and mode of treatment could not be linked to neuropsychological outcome. The time length of volume-controlled mechanical ventilation as a reflector of the aggregated consequences of being subjected to an aneurysm rupture correlated with both motor and psychomotor functioning and memory performance, predominantly 6 to 12 months after SAH, but was not linked to intelligence or aphasia. CONCLUSIONThe various cognitive functions have different time courses of recovery, with verbal memory requiring the longest time. Parameters reflecting the impact of the bleed and patient management can be linked to neuropsychological outcome.

Long-Term Outcome after Resection of Benign Cerebellar Astrocytomas in Children and Young Adults (0–19 Years): Report of 110 Consecutive Cases

The objective of this retrospective study was to present long-term follow-up data for 110 consecutive children and young adults treated for a benign cerebellar astrocytoma at our institution between 1960 and 2001. Mean age at presentation was 8.9 years. The total surgical mortality was 9%, but declined from 16% in 1960–1977 to 0% in 1988–2001. At the close of the study 97/110 patients were still alive. Nine deaths were surgery related, 2 patients died of shunt-related causes and 2 patients died due to tumor recurrence. Five-, 10- and 25-year survival were 90, 89 and 85%, respectively. Multiple Cox regression analysis showed that tumor infiltration of the brain stem and the time period of surgery were the only explanatory variables significantly associated with survival. Five-year survival improved from 79% in the time period of 1960–1977 to 100% in the time period of 1988–2001. Tumor recurrence after total tumor resection was observed in 5 of 76 (7%) evaluable patients. Growth of residual tumor after subtotal tumor resection was observed in 7 of 26 (27%) evaluable patients. Recent follow- up MR revealed regression of residual tumor in 14 of 16 patients. Only 5 of these patients had received radiotherapy. Thus, spontaneous regression of residual tumor is a more frequent event than growth of residual tumor. The functional outcome was favorable in 82% of the patients [Karnofsky performance index (KPI) ≧90]. Eighteen percent of the patients had moderate to severe disabilities (KPI 50–80). Conclusions: Benign cerebellar astrocytoma is a surgical disease where the prognosis with respect to both survival and functional outcome is favorable. Spontaneous regression of residual tumor is frequently encountered, allowing for observation of residual tumors instead of performing a second resection in cases where a second resection carries a high risk of neurological sequelae.

Head injuries during one year in a central hospital in Norway: a prospective study. Epidemiologic features

Annual age-adjusted incidence rate of head injuries in Akershus County in 1974 was estimated to be 236/100,000, 307/100,000 for males and 164/100,000 for females. The highest incidence rate occurred in males in the age group 10-19 years (489/100,000) and the lowest among females in the age group 30-39 (68/100,000). In all age groups, the incidence rate was higher in males than females. This prospective study included 488 patients, of whom 88.9% had minor head injuries and 11.1% severe head injuries. 16 patients (3.3%) died due to their head trauma. Skull fracture was detected in 10.4% of the patients who survived the first 24 h, and 2.5% had operations. The mean hospital stay was 8.8 days, 10.2 days for the patients injured in traffic accidents and 7.0 days for the others. Besides having a higher incidence rate of head injuries, males suffered severe head injuries more often and their death rate was higher than head-injured females.

Cognitive functioning and health-related quality of life 1 year after aneurysmal subarachnoid hemorrhage in preoperative comatose patients (Hunt and Hess Grade V patients).

OBJECTIVEThe objective of this study was to determine cognitive functioning and health-related quality of life 1 year after aneurysmal subarachnoid hemorrhage in preoperative comatose patients (Hunt and Hess Grade V patients). METHODSPatients who were comatose at hospital arrival and thereafter were investigated for 1 year using a comprehensive neuropsychological test battery and 2 HRQOL questionnaires. RESULTSThirty-five of 70 patients survived the bleed, and 26 underwent neuropsychological testing. Two distinct patient groups emerged, one (n = 14) with good cognitive function, having mild deficits only, and the other (n = 12) with poor cognitive and poor motor function. Patients performing poorly were older (P = .04), had fewer years of education (P = .005) and larger preoperative ventricular scores, and were more often shunted (P = .02). There were also differences between the 2 groups in the Glasgow Outcome Scale (P = .001), the modified Rankin Scale (P = .001), and employment status. HRQOL was more reduced in patients with poor cognitive function. CONCLUSIONA high fraction of survivors among preoperative comatose aneurysmal SAH patients (Hunt and Hess grade V) recover to good physical and cognitive function, enabling them to live a normal life.

Choroid plexus tumors in children and young adults: report of 16 consecutive cases.

Abstract Choroid plexus tumors are rare intraventricular tumors, and they represent 2–4% of brain tumors in children. This single-institution retrospective study involves 16 consecutive choroid plexus tumors: 13 papillomas and 3 carcinomas. Tumor locations were the lateral ventricles in 13 cases, the third ventricle in 2 cases and the fourth ventricle in 1 case. The mean age at presentation was 3.1 years. Two patients died of perioperative blood loss. Five-year survival was 85% with papillomas and 33% with carcinomas. None of the papillomas recurred after total tumor resection, and the functional outcome in long-term survivors after papilloma surgery was excellent in 92% of the cases. Two of the carcinoma patients had disseminated disease. Fifty percent of the patients had persistent hydrocephalus after tumor resection, and these required cerebrospinal fluid diversion.

Some Observations on Cerebral Perfusion during Cardiopulmonary Bypass

Blood flow was recorded with an electromagnetic flow probe on one internal carotid artery (ICA) during cardiopulmonary bypass (CPB) in 5 patients. The ICA flow was monitored continuously along with arterial blood pressure, epidural intracranial pressure, and cerebral electrical activity using a cerebral function monitor (3 patients). The ICA flow increased by 50 to 100% at the inception of extracorporeal circulation. This rapid enhancement of flow occurred within a thirty-second period and was due to rapid arterial hemodilution caused by introduction of the priming solution. A transitory fall in ICA flow was observed during subsequent minutes when the well-recognized drop in blood pressure took place and the cerebral perfusion pressure (CPP = blood pressure - epidural intracranial pressure) was reduced to less than 30 mm Hg. In only one instance, however, when CPP fell to 15 mm Hg, was the fall in flow lower than the prebypass level. Throughout the rest of CPB, with steady-state hemodilution and CPP levels in the range of 30 to 50 mm Hg, ICA flow was markedly enhanced (50 to 100% above the prebypass level). The flow pattern, however, disclosed a pressure-passive system, indicating that cerebral autoregulation was impaired or that the CPP levels were lower than the individual lower limit of cerebral autoregulation during the period of steady-state hemodilution on CPB. A transient depression of cerebral electrical activity was seen in 2 patients shortly after the introduction of CPB. This phenomenon is suggestive of qualitatively insufficient perfusion and was observed even when ICA bulk flow was increased (hematocrit values, 13 to 17%).

Assessment of Continuous Intracranial Pressure Recordings in Childhood Craniosynostosis

In this study, we explored two strategies of assessing continuous intracranial pressure (ICP) recordings in children with craniosynostosis, namely either by computation of the mean ICP or by computation of the accurate numbers of ICP elevations of different durations. The ICP recordings of 121 consecutive patients with a tentative diagnosis of craniosynostosis who underwent continuous ICP monitoring were examined. The relationship between mean ICP and numbers of ICP elevations was defined. The distribution of numbers of ICP elevations between patients either undergoing surgery or conservative treatment was also compared, since the choice of treatment was heavily dependent on the results of ICP monitoring. At the time of ICP monitoring, calculation of mean ICP was the main parameter for assessment of ICP curves. After a median observation period of 16 months, the ICP curves were reexamined by means of the software SensometricsTM Pressure Analyser, which presents the ICP curve as a matrix of numbers of ICP elevations of different levels (20–40 mm Hg) and durations (0.5– 20 min). Since the recording period differed between the cases, the numbers were standardized to a given recording time of 10 h, to allow for comparisons between patients. Cases with a borderline mean ICP during sleep (mean ICP 10–15 mm Hg) constituted 40.5% of the 121 patients. In this group, a rather weak relationship between mean ICP and the number of ICP elevations above 20 mm Hg was found, as well as a relatively high number of ICP elevations above 20 mm Hg of various durations. As compared to the patients undergoing surgery, a rather high number of ICP elevations above 20 mm Hg of various durations was found in patients undergoing conservative treatment. The study confirmed our hypothesis that in children with craniosynostosis, calculation of mean ICP does not describe the ICP curve in a reliable way. Decision-making should also include the computation of the distribution of numbers of ICP elevations, since this procedure represents a more sensitive strategy of detecting intracranial hypertension.