HMPAO-SPECT Can Discriminate between Patients with Subjective Cognitive Complaints with and without Cognitive Deficits and those with Mild Cognitive Impairment

BACKGROUND

Growing evidence suggests that pathological processes leading to Alzheimer's disease occurs gradually and begins to develop decades before the earliest clinical symptoms occur. The use of biomarkers has been proposed to detect evidence of preclinical Alzheimer's pathologic change in asymptomatic subjects. Subjective cognitive complaints (SCC) i.e. self-reported cognitive decline with normal cognition have been reported as an indicator of future cognitive decline, however, this condition is unspecific.

OBJECTIVE

In the present study we used the regional brain perfusion measured by HMPAO-SPECT as Biomarker of neurodegeneration to compare the regional brain perfusion of patient with subjective cognitive complaints with and without minimal cognitive dysfunction (SCC+ and SCC- respectively) in respect to patients with mild cognitive impairment (MCI).

METHODS

We retrospectively examined 736 Patients who referred to our Memory Clinic because of suspected cognitive dysfunction. After exclusion of patients with overt dementia, automated, quantitatively assessed relative cerebral blood flow of 10 forebrain regions (thalamus, parietotemporal, medial temporal, posterior temporal, posterior cingulate gyrus, each region left hemispheric and right hemispheric) and neuropsychological assessment of 64 SCC (32 SCC+; 32 SCC-) and 28 MCI subjects were analysed.

RESULTS

.The most relevant differences between groups in cognitive performance concerned verbal memory. Left hemispheric medial temporal region could significantly discriminate between all three groups, with a progressive decrease n perfusion from SCC towards MCI. Area under the curve of left medial temporal region showed a sensitivity of 0,61 and a specificity of 0,78 for discriminating MCI from SCC.

CONCLUSION

Automated analysis of HMPAO-SPECT data of MCI and SCC+ patients showed significant perfusion differences in medial temporal region and impaired verbal memory, both of which are known features of Alzheimer's disease. Perfusion patterns and verbal memory performance in SCC+ are more similar to MCI than SCC-. Thus, SPECT analysis could distinguish those subjects whose perfusion pattern resembles that of an MCI from those who do not. In our opinion, this could identify two populations with a different risk of progression to AD, with SCC+ subjects needing further diagnostic examination and repeated follow-up.

Adhesion molecules are promising candidates to establish surrogate markers for natalizumab treatment

BACKGROUND

Natalizumab is the first monoclonal antibody therapy approved for multiple sclerosis (MS). Its therapeutic mechanism is the blockade of the α4-integrin subunit of the adhesion molecule (AM) very late activation antigen-4 (VLA-4), which leads to an inhibition of immune cell extravasation into the central nervous system (CNS).

METHODS

We investigated changes in the expression levels of unblocked α4-integrin and further AM (intercellular adhesion molecule-1, -2, -3 (cICAM-1, -2, -3), leukocyte function associated antigen-1 (LFA-1)) on peripheral blood mononuclear cells (PBMC) determined by flow cytometry from 25 patients with MS before the first natalizumab infusion and before the fourth infusion. In 15 MS patients AM expression was evaluated every 3 months over 1 year.

RESULTS

We found a significant decrease (p < 0.0001) of unblocked α4-integrin cell surface expression on all investigated PBMC subsets (T cells -61.7%, B cells -69.1%, monocytes/macrophages -46.4%) in the blood of MS patients after 3 months of natalizumab treatment. Moreover, a continuous decrease (p < 0.05) of unblocked α4-integrin expression levels was seen after 3, 6, 9, and 12 months. As a secondary effect, expression levels of the other investigated AM were differentially affected.

CONCLUSIONS

Results show a sustained decrease of unblocked α4-integrin expression not only in all patients but also in all investigated PBMC subsets. This probably results in a continuously decreasing transmigration of PBMC into the CNS and may explain the improved clinical efficacy in the second treatment year and also the increasing risk of progressive multifocal leukoencephalopathy during long-term natalizumab therapy. We conclude that AM expression profiles are promising candidates for the development of a biomarker system to determine both natalizumab treatment response and patients at risk for opportunistic CNS infections.

Cerebral perfusion (HMPAO-SPECT) in patients with depression with cognitive impairment versus those with mild cognitive impairment and dementia of Alzheimer's type: a semiquantitative and automated evaluation

PURPOSE

Comparative evaluation of regional brain perfusion measured by HMPAO-SPECT of patients with mild cognitive impairment (MCI), dementia of Alzheimer's type (DAT) and depression with cognitive impairment (DCI).

METHODS

A total of 736 patients were investigated because of suspected cognitive dysfunction. After exclusion of patients with other forms of dementia than DAT or relevant accompanying disorders, SPECT data from 149 MCI, 131 DAT and 127 DCI patients, and 123 controls without any cognitive impairment, were analysed. Relative cerebral blood flow of 34 anatomical regions was assessed with automated analysis software (BRASS).

RESULTS

Calculation of global forebrain perfusion discriminated demented from nondemented patients. Compared to controls DCI patients showed hypoperfusion of the thalamus, lentiform nucleus and medial temporal cortex. MCI patients differed significantly from controls concerning perfusion in both hemispheric temporal and parietal areas, and in the (right hemispheric) posterior part of the cingulate gyrus. MCI and DCI patients differed in the parietal, temporal superior and right hemispheric cingulate gyrus posterior cortices. Global forebrain and regional perfusion was more extensively reduced in DAT patients and discriminated them from controls, and MCI and DCI patients. Frontal perfusion disturbance was only present in DAT patients.

CONCLUSION

Automated analysis of HMPAO-SPECT data from MCI patients showed significant perfusion deficits in regions also involved in DAT patients, but ROC analysis demonstrated only moderate sensitivity and specificity for differentiating DAT patients from controls and DCI patients. Frontal hypoperfusion seems to correspond with conversion from MCI to DAT. Finally, the results in DCI patients again raise the question of depression as an early symptom of neurodegeneration.

Brain perfusion SPECT in patients with mild cognitive impairment and Alzheimer's disease: comparison of a semiquantitative and a visual evaluation

Due to the increasing importance of early recognition and differential diagnosis of dementias, cerebral perfusion scans using "single photon emission computed tomography" (SPECT) are increasingly integrated into the examination routine. The goal of this study was to check the diagnostic validity of SPECT scans of MCI- and DAT-patients, two subgroups out of 369 persons with etiologically unclear cognitive dysfunction, which underwent an assessment program for probable dementia including cognitive testing, cranial computed tomography, ultrasound, routine laboratory testing including vascular risk factors. After exclusion of patients with no or other forms of dementia we analyzed SPECT data of patients with mild cognitive impairment (MCI; n = 85) and dementia of the Alzheimer type (DAT; n = 78) in comparison with a healthy control group (n = 34).Visual assessment as well as a manual "regions of interest" (ROI) regionalization of the cortex were performed, whereby a ROI/cerebellum ratio was calculated as a semi-quantitative value. Association cortex areas were assessed regarding frontal, temporal, and parietal lobes of both hemispheres. When comparing the ratios of patients with DAT and controls, we found a statistically significant reduction of the cerebral perfusion in all measured cortex areas (p < 0.001). The comparison of patients with MCI with the selected control group also established a statistically significant difference in the cerebral perfusion for the evaluated cortex areas with the exception of the left hemispheric frontal and parietal cortex.A considerable number of the MCI patients showed an MMSE-score within the normal range, but with regard to the perfusion in the right hemispheric association cortex these patients also could be distinguished unambiguously from controls. Sensitivity levels found by visual assessment were at least as high as those found by the ROI method (pathological assessment: visual 49.4% vs. ROI 47.1% for MCI; visual 75.6% vs. ROI 73.1% for DAT). High experienced visual assessment of cerebral perfusion scans using SPECT provides an useful additional tool in diagnosis of cognitive impairment. The used semiquantitative ROI-method is nearly equivalent and does not depend on the experience of the investigator.

Inadequate management of cerebrovascular risk factors in participants of a public stroke prevention program in Austria

The aim of our investigation was to identify frequencies and treatment quality of stroke risk factors in participants of a stroke prevention program in the province of Salzburg (Austria). A total of 9356 participants free of previous stroke were classified in three risk categories for suffering from ischemic stroke within the next 10 years and analyzed referring to history, therapy, and treatment quality of cerebrovascular risk factors. A total of 6519 (69.7%) participants were classified to be at low (<10%), 2232 (23.9%) at intermediate (10-20%) and 605 (6.5%) at high risk (>20%). Elevated blood pressure with the need for follow-up investigations was found in 5193 persons (55.5%); of 3713 (39.7%) persons with a history of hypertension, 3204 (86.3%) are under medical treatment, which is sufficient only in 765 patients (23.9%). Similar results were present for other well documented modifiable risk factors. In the investigated population there is high presence of stroke risk factors with inadequate treatment in most cases.

Brief report: melatonin facilitates sleep in individuals with mental retardation and insomnia

Mentally retarded people typically exhibit poor sleep efficiency and reduced nocturnal plasma melatonin levels. The daytime administration of oral melatonin to those people, in doses that raise their plasma melatonin levels to the nocturnal range, can accelerate sleep onset. We examined the ability of similar, physiological doses to restore nighttime melatonin levels and sleep efficiency in mentally retarded subjects with sleep deficits. In a double-blind, placebo-controlled study, mentally retarded subjects (n = 20) received, in randomized order, a placebo and two melatonin doses (0.1, and 3.0 mg) orally 30 minutes before bedtime for a week. Treatments were separated by 1-week washout periods. Sleep data were obtained by polysomnography on the last three nights of each treatment period. The physiologic melatonin dose (0.3 mg) restored sleep efficiency (p < 0.0001), acting principally in the midthird of the night; it also elevated plasma melatonin levels (p < 0.0008) to normal. The lowest dose (0.1 mg) also improved sleep.

Tianeptine: a novel strategy of psychopharmacological treatment of children with autistic disorder

OBJECTIVES

Many autistic children have problems of eye contact and expressive language that limit the effectiveness of educational and behavioural interventions. Few controlled psychopharmacological trials have been conducted in autistic children to determine which agents may be effective for these associated features.

METHODS

Twelve male children (7.3 +/- 3.3 years) with autistic disorder, diagnosed by ICD-10 criteria, completed a placebo-controlled, double-blind crossover trial of tianeptine, which lasted for 12 weeks. Subjects were included in the study if their eye contact and expressive language was inadaequate for their developmental level. Subjects had not tolerated or responded to other psychopharmacological treatments (neuroleptics, methylphenidate, clonidine or desipramine).

RESULTS

Teacher ratings on the aberrant behaviour checklist irritability, stereotypy and inappropriate speech factors were lower during treatment with tianeptine than during treatment with placebo. Clinician ratings (children's psychiatric rating scale autism, anger and speech deviance factors; children's global assessment scale; clinical global impressions efficacy) of videotaped sessions were not significantly different between tianeptine and placebo.

DISCUSSION

Tianeptine were modestly effective in the short-term treatment of irritability in some children with autistic disorder.

Family coherence and ADHD

A lack of perseverance, poor attention, and poorly modulated behaviour are important criteria of Attention Deficit Hyperactivity Disorder (ADHD). Instructions often must be repeated, sometimes even by different family members, before a child with ADHD attends and complies. The hyperkinetic child might cause less disruption in families with high coherence. Families of 15 boys (aged 6 to 12 years) diagnosed with ADHD using the Mannheim Parent's Interview and the teacher's form of the Conners scale were compared with a matched healthy control group of 15 boys. Parents completed a form assessing the family's cooperation and childrearing practices. Intrafamilial coherence seems to have little positive association with the family's characteristics, especially for boys with Attention Deficit Hyperactivity Disorder. Low coherence among family members may reduce ADHD symptoms and may have protective effects on children with ADHD.

Features in families and family relationships

Standardized assessment of family features is not used routinely, although these factors may play an important role in the course of children's psychological disorders. The present study investigated the association among relationships within the families of 115 healthy children (M=8.2 yr., SD=2.13; 70 boys, 45 girls). 115 mothers and fathers were asked to complete a standardized questionnaire assessing the family features (Familienklima-Testsystem by Schneewind, et al.) and another asking for their estimation of emotional relationships of the members of the family (Subjektives Familianbild-Test System by Mattejat). Analysis showed that the parents' ratings indicated significantly more empathic fathers as well as significantly more autonomous mothers in well-organized, conflict-free families. Our results indicate an association between families' organization and measured scores for fathers' empathy and mothers' autonomy. Sufficient intrafamilial communication is associated with roles of the parents within the family. Psychotherapeutic interventions might focus on the families' organization.

Cognitive function and fMRI in patients with multiple sclerosis: evidence for compensatory cortical activation during an attention task

Mild cognitive impairment has frequently been reported for patients in the early stages of multiple sclerosis. The aim of the present study was to measure whether altered cortical activation during a sustained attention task occurs along with limited extent of neuropsychological problems. Expanded brain activation of multiple sclerosis patients with normal motor function compared with healthy controls during a finger tapping paradigm has previously been reported. Compensatory brain activation in patients with multiple sclerosis compared with normal controls may also be observed when the subjects are performing cognitive functions. In 21 patients with clinically definite relapsing-remitting multiple sclerosis, a psychometric assessment was performed using the Wechsler Memory Scale (WMS) and the Multiple Sclerosis Functional Composite Score (MSFC). In addition, functional MRI was performed during a Paced Visual Serial Addition Task (PVSAT), a visual analogue of the Paced Auditory Serial Addition Task (PASAT). All patients were within 3 years of diagnosis and were not suffering from a relapse at the time of investigation. The multiple sclerosis patients were compared with a control group of 21 healthy volunteers matched for handedness, age, years of education and sex. With regard to psychometric results, the WMS general memory score showed statistically significant differences between patients and controls. We did not find differences for either the MSFC or the PASAT scores. A group analysis of the functional imaging data during the PVSAT revealed different activation patterns for patients compared with control subjects. In healthy volunteers, the main activation was found in the frontal part of the right gyrus cinguli (Brodmann area 32). In patients, the main activation was detected at the right hemispheric frontal cortex (Brodmann areas 6, 8 and 9). In addition, the left hemispheric Brodmann area 39 was activated. We interpret the different patterns of activation, accompanied with intact performance in a sustained attention task of our multiple sclerosis sample compared with healthy controls, as the consequence of compensatory mechanisms. This is an expression of neuronal plasticity during early stages of a chronic disease.

Features in Families and Family Relationships

Standardized assessment of family features is not used routinely, although these factors may play an important role in the course of children's psychological disorders. The present study investigated the association among relationships within the families of 115 healthy children ( M = 8.2 yr., SD = 2.13; 70 boys, 45 girls). 115 mothers and fathers were asked to complete a standardized questionnaire assessing the family features (Familienklima-Testsystem by Schneewind, et al.) and another asking for their estimation of emotional relationships of the members of the family (Subjektives Familianbild-Test System by Mattejat). Analysis showed that the parents’ ratings indicated significantly more empathic fathers as well as significantly more autonomous mothers in well-organized, conflict-free families. Our results indicate an association between families’ organization and measured scores for fathers’ empathy and mothers’ autonomy. Sufficient intrafamilial communication is associated with roles of the parents within the family. Psychotherapeutic interventions might focus on the families’ organization.

Measuring the progression of idiopathic Parkinson's disease with [123I] beta-CIT SPECT

Idiopathic Parkinson's disease (PD) is the most common neurodegenerative disorder. An important step in diagnosing the disease has been achieved with the development of the cocaine derivative [123I] beta-CIT for single photon emission computed tomography (SPECT). The aim of this study was to demonstrate the disease progression by repeated measuring presynaptic dopamine transporter density and relating it to clinical data.

METHODS

The presynaptic dopamine transporter density of 15 PD patients was measured two times with a mean interval of 15 months. All patients were clinically assessed at the time of the experiments according to the classification scheme of Hoehn and Yahr. 11 healthy volunteers were used as a control group. [123I] [-CIT was injected intravenously and measured with a triple-headed camera twenty hours later. The pictures were evaluated semiquantitatively by using the ratio of specific to non-displaceable binding.

RESULTS

Presynaptic dopamine transporter density differed significantly between controls and PD patients. A significant correlation between imaging data and clinical stages (H/Y I -27%, H/Y II -40%, H/Y III -58%) was observed for the patient group in the initial experiment. The subsequent decrease of dopamine transporter binding depended on the initial clinical stage (H/Y I -6.81%; H/Y II -6.05%; H/Y III -1.25%) of the patients, and regression analysis revealed that. 91.4% of the variance of the second measurement were predicted by the initial measurement. No correlations were found for age, gender and disease progression. All patients were treated with L-DOPA and those given a higher dose showed a more rapid decrease of dopamine transporter density. This result could be interpreted as an indication for in vivo neurotoxicity of high concentrations of L-DOPA.

CONCLUSION

We conclude that combining [123I] beta-CIT with SPECT imaging is not only a powerful tool for diagnosing PD patients, but may also be used to demonstrate neurodegeneration in vivo.

Imaging the basilar artery by contrast-enhanced color-coded ultrasound

Conventional transcranial color-coded real-time sonography of the vertebrobasilar system is limited by imaging problems of the distal segment of the basilar artery. Lung-stable contrast-enhancing agents may overcome this problem by enhancing the quality of Doppler signals by as much as 20%. Fourty-two patients underwent sonographic evaluation of the vertebrobasilar system before and after receiving intravenously administered galactose-based contrast-enhancing agent Levovist by transforaminal and transtemporal routes. Imaging quality was classified into five categories depending on the length of visible color-flow by transforaminal approach: 1--no signal, 2--1-9.9 mm, 3--10-19.9 mm, 4--20-29.9 mm, 5--> or = 30 mm. For transtemporal insonation, imaging quality was classified either as no color flow or sufficient color flow of the basilar tip. By unenhanced investigation, average signal length of color flow was 16 +/- 8 mm for transforaminal investigation; application of Levovist improved this value to 26.6 +/- 6 mm. For unenhanced transforminal approach, 4.8% were assigned to category 1, 11.9% to category 2, 54.8% to category 3, 23.8% to category 4 and 4.8% to category 5. After signal enhancement with Levovist, category 1 covered 0%, category 2 2.4%, category 3 7.14%, category 4 59.5% and category 5 30.9% (p < 0.001). Unenhanced transtemporal approach allowed identification of the basilar tip in 78.6% with an average length of 6.3 +/- 2 mm; contrast enhancement improved this values to 92.9% and 8.3 +/- 3.3 mm respectively (p < 0.05). The application of transpulmonary contrast-enhancing agents improves the reliability of transcranial color-coded duplex sonography of the basilar artery.

Delayed visual P3 in unilateral thalamic stroke

The P3 potential is accepted as a neurophysiological correlate of memory and attention. Delayed latencies were reported in different forms of dementias. Although the generator sites are still under debate, the thalamus may play a crucial role. The aim of this study was to investigate the influence of an unilateral thalamic ischaemic infarction on P3 generation. The event-related P3 component of six patients (2 male, four female; mean age 47 years, range 22-63 years) with unilateral thalamic ischaemic infarction was studied and compared to age-matched controls (five male, nine female; mean age 45.8 years; range 22-69 years). All patients underwent full clinical examination, CCT, and MRI scan. P3 potentials were recorded with a visual three stimulus discrimination paradigm. The mean P3 latency of the patient group to the target stimulus was delayed (469.7 ms, SD = 36.8) compared with the controls (378.8 ms, SD = 51.5; P < 0. 05). The mean P3 latency to the unexpected stimulus was delayed in patients with thalamic infarction compared with controls [477 ms (SD = 46.6) vs. 381.2 ms (SD = 48.5); P < 0.001). Delayed P3 components of the event-related potential (ERP) were recorded in six patients with unilateral thalamic infarction, suggesting an important role of the thalamus in the generation of the P3 potential.

[Improving the visibility of intracranial vessels with the echo-enhancing substance Levovist in duplex sonography]

AIM

To evaluate the diagnostic advantages of Levovist for contrast enhancement of intracranial arteries in a routine clinical setting.

METHOD

Routine cerebrovascular extracranial Doppler- and duplex-sonography was performed in 3990 patients (1791 female, 2189 male, mean age 50.4 years). In addition 879 trans-temporal, 990 trans-foraminal and 99 trans-orbital trans-cranial colour-coded duplex investigations were performed on these patients. Signal quality was classified in the categories: 'no signal', 'insufficient signal' and 'sufficient signal'. Patients classified as having 'no' or 'insufficient' signal quality underwent an additional examination after application of Levovist.

RESULTS

879 patients underwent trans-temporal examination. In 89 (9.1%) of these patients signal quality in the trans-temporal examination proved to be insufficient, thus indicating the use of Levovist. 346 of the examined vessels (72%) were originally classified as showing 'no signal'; this number could be reduced to 82 (23.9%) after applying Levovist. Of the 99 arteries (21%) falling into the category 'insufficient signal', only 4 (4%) did not show signal improvement after application of Levovist. 990 patients were examined by the trans-foraminal approach, and Levovist was given to just 26 patients (2.6%). Without enhancement, 20 basilar arteries (77%) showed 'no' or 'insufficient' signal, whereas after injecting Levovist only 4 (13.25%) remained in these categories. Of 13 vertebral arteries (25%) with 'no' or 'insufficient' signal intensity, 3 (5.8%) showed no improvement in imaging quality after application of Levovist.

CONCLUSION

Imaging problems of intracranial arteries are dramatically reduced by Levovist.

[123I] beta-CIT binding and SPET compared with clinical diagnosis in parkinsonism

The largest group of neurodegenerative disorders are extrapyramidal diseases, especially parkinsonism. The development of the cocaine derivative [123I] beta-CIT and single photon emission tomography (SPET) may help in the diagnosis of these patients. The aim of this study was to demonstrate the diagnostic value of this method and its relationship with clinical data. Ninety-eight individuals were investigated: 11 healthy volunteers, 58 patients with idiopathic Parkinson's disease (IPD) and 29 patients with symptomatic parkinsonism (SPD). All patients with parkinsonism were staged according to the clinical classification of Hoehn and Yahr. [123I] beta-CIT was injected intravenously and a triple-headed camera was used to obtain images 20 h later. The images were evaluated visually and semi-quantitatively to obtain comparable values (ratio: specific to non-displaceable binding). The ratios differed significantly between controls and IPD patients. A significant correlation also existed between the ratios and clinical stages. In 11 hemiparkinsonian patients, a significantly diminished ratio was demonstrated not only contralateral to the affected side, but also in the clinically silent striatum. A clinical threshold at a reduction of 34% [123I] beta-CIT binding was calculated in this group. The ratios of all SPD patients in our study did not differ significantly from those of the healthy volunteers. According to the clinical degree of symptoms, the more severe subgroup showed a diminished mean ratio of 22% and therefore could not be clearly differentiated from mild IPD. In contrast, ratios were significantly different when comparing groups of the same clinical severity. We conclude that this method is not only a powerful diagnostic tool in IPD patients, but it is also possible to differentiate between IPD and SPD patients, if clinical aspects are also included.

Lateralized cognitive visuospatial processing: is it primarily gender-related or due to quality of performance? A HMPAO-SPECT study

The brain activity of 13 right-handed students (6 men and 7 women) was determined using high resolution (99m)Tc-HMPAO brain SPECT images during visuospatial tasks. The results showed that there was no significant gender-specific difference in solving the visuospatial tasks and that no meaningful statistical difference in brain activity between the two sexes could be found. When the sample was split into groups of good and poor performers, the results showed that there was a relatively symmetrical brain activity both frontal and parietal in subjects with poor test results. The results for those who performed the tests well, on the other hand, showed increased left frontal and right parietal brain activity. These results would suggest an asymmetric type of processing for better visuospatial brain performance independent of gender.

Multimodal event-related potential P3 after transient global amnesia

The putative generators of the event-related P3 component are still a matter of debate. There is reasonable evidence that the mesial temporal lobe structures are crucial in the generation of event-related potentials. Transient global amnesia (TGA) is characterized by anterograde and retrograde amnesia without neurological deficits in which a temporal hypoperfusion is the most likely pathomechanism. The aim of this study is to evaluate a possible delay in the P3 latency in a cohort of patients with TGA (n = 18). We used classic oddball paradigms with visual and auditory stimuli. The P3 latencies were compared to 18 age-matched patients with transient ischaemic attacks (TIAs) in the carotid artery territory and 23 age-matched controls. The mean age of the patients was 60.1 years (SD 14.1), in the TIA group 64.7 (SD 12.1) and 57.7 (SD 10.1) in the controls; the mean time interval between onset of TGA symptoms and performance of P3 investigations was 4.3 days (range 1-7 days); and the mean latencies measured at the vertex (Cz electrode) were 422.9 ms (SD 44.6) for the TGA patients, 436.4 ms (SD 62.1) for the TIA group, and 409.3 ms (SD 48.5) for the controls in the visual paradigm and 371.7 ms (SD 41.7), 399.7 ms (SD 51.2) and 385.3 ms (SD 46.5) in the auditory paradigm for the TGA, the TIA and the control groups. The P-values were not significant. These results suggest different neuronal networks in the generation of scalp P3 from those responsible for the disturbance of episodic memory in TGA.

Clinical and EEG findings in complex partial status epilepticus with tiagabine

A case of complex partial status epilepticus (CPSE) with high dose treatment of tiagabine (TGB) is reported. Seizure aggravation and CPSE developed after stepwise increase of TGB to a dose of 60 mg per day as add-on treatment to carbamazepine (CBZ) 1200 mg/day and vigabatrine (VGB) 1000 mg/day. The EEG during CPSE showed bilateral rhythmic slow activity. Clinical symptoms of CPSE and the EEG normalized after i.v. treatment with clonazepam. The literature and the possible mechanism of this paradoxical phenomenon are discussed.

The effect of lidocaine on chronic tinnitus: a quantitative cerebral perfusion study

The cerebral perfusion of a 55-year-old female patient with chronic tinnitus was investigated quantitatively by single photon emission computed tomography (SPECT) with the xenon133 inhalation method. The first investigation was performed under standard conditions, the second during suppression of tinnitus with intravenous injection of lidocaine. As a reference a healthy volunteer was included under the same conditions. The global cortical perfusion was identical on both sides except for increased perfusion in the auditory cortex, especially on the right side when tinnitus lasted during the first measurement. The second investigation under treatment with lidocaine and during the tinnitus-free interval showed a decrease of the global cortical perfusion with a slightly higher value at the temporal cortex bilaterally. In comparison to the first investigation, a difference between right and left auditory cortex could no longer be demonstrated, and also the difference between regional and global perfusion decreased. A cerebral effect under treatment of tinnitus with lidocaine was shown by the quantitative measurement of brain perfusion. It is debatable whether this effect on cerebral activity results from the medication or as a reaction to the tinnitus-free interval.

Clinical relevance of 201Tl-chloride SPET in the differential diagnosis of brain tumours

Magnetic resonance imaging (MRI) and computed tomography (CT) may not be reliable in the differential diagnosis of tumour necrosis, scar and recurrent tumour. We compared 201Tl-chloride SPET with CT and MRI for the differential diagnosis of these cerebral lesions. Brain SPET was performed in 40 patients after the intravenous injection of 201Tl-chloride. All 40 patients also had a CT or MRI scan, and a histological diagnosis was available for 27 of the patients. For each patient, the ratio of counts in the lesion region of interest (ROI) to counts in the contralateral ROI was calculated and found to be between 0.58 and 9.60. The ratios for high-grade gliomas, metastases and meningiomas were high (> 2.7), especially in tumours with good vascularization. A low ratio (< 1.7) was noted in patients with low-grade astrocytoma, necrosis or ischaemic lesions. There were two exceptional cases of ischaemic lesions in the luxury perfusion stage (ratios of 3.61 and 3.87), as verified by HMPAO-SPET. We found that 201Tl-chloride SPET helps to differentiate between malignant tumours, poorly vascularized benign lesions and necrosis. Differentiation between low-grade astrocytoma and non-malignant lesions was not possible, but there was a trend towards differentiating between low-grade astrocytoma and ischaemic infarction. The timing of the investigation is important to avoid false-positive results in hyperperfused ischaemic tissue.

SPET investigations in extrapyramidal diseases using specific ligands

Single photon emission tomographic investigations of the extrapyramidal system have become easier to perform since the development of the ligands [123I]-beta-CIT and [123I]-IBZM. Thirty-three patients were investigated with [123I]-IBZM. The images were evaluated visually and semi-quantitatively (ratio of the striatum to front cortex). Ten controls showed a mean (+/- S.D.) ratio of 1.513 +/- 0.06; nine patients with Parkinson's disease had a smaller ratio of 1.425 +/- 0.095; six patients with Huntington's disease had a significantly lower ratio (1.147 +/- 0.105). Eight patients were not classified, because of different nosologic entities. Twenty-three patients were investigated with [123I]-beta-CIT. They were evaluated using standard techniques and the ratio of the striatum to cerebellum. Six controls had a mean ratio of 5.128 +/- 0.787. In 11 Parkinson patients, the ratio was significantly less (3.359 +/- 0.769). Patients with focal dystonia showed normal values. One patient with Huntington's disease had a significantly lower ratio. Receptor studies of the extrapyramidal system may help with diagnoses and could be of relevance therapeutically.

Clinical and diagnostic findings in a patient with Creutzfeldt-Jakob disease (type Heidenhain)

A 61-year-old woman had Creutzfeldt-Jakob disease, type Heidenhain, that progressed for 4 months until death, 3 of which she spent in a hospital. The diagnosis was verified by autopsy. Consecutive brain computed tomography, magnetic resonance imaging, blood flow measurements, electroencephalography (EEG), and routine laboratory tests were performed. All imaging techniques showed nonspecific pathological changes, whereas EEG revealed alterations indicative for Creutzfeldt-Jakob disease.

[Magnetic resonance tomography and skeletal scintigraphy in spondylodiscitis]

12 patients were diagnosed as suffering from spondylodiscitis by means of clinical and laboratory investigations. Magnetic resonance tomography (MRT) and bone scintigraphy (with Tc 99m-diphosphonate) were performed and 6 patients had further MRT follow up investigations. In the initial state of disease the comparison of MRT and bone scan both revealed a sensitivity of 92%. The specificity was 83% for MRT and 50% for bone scintigraphy, respectively. Therefore we conclude MRT is a more specific diagnostic tool in patients with spondylodiscitis. 6 patients were followed up with additional 13 MRT scans. During the first two months of treatment period in most of the patients more distinct pathological findings were seen in MRT in comparison with MRT at the start. No signs of any improvement despite effective treatment were found in the first three months of therapy.

[Functional significance of calcinosis of the basal ganglia via positron emission tomography]

Four patients with symmetrical basal ganglia calcification of different etiologies detected by cranial computed tomography (CT) were clinically evaluated and underwent positron emission tomography (PET) with (18F)-2-fluoro-2-deoxy-D-glucose (FDG). All patients were subjected to extensive laboratory investigation and neuropsychological testing. In two patients we found typical laboratory signs of hypoparathyroidism, the other two patients had no endocrinological alterations. Changes of glucose metabolism were mainly detected only in calcified tissues. Particularly in two patients with test psychologically confirmed psychomotoric retardation we did not find any cortical dysfunction. In conclusion, basal ganglia calcification in contrast to primary degenerative diseases has no influence on metabolic function in tissue that is not calcified.

[The diagnostic value of nuclear magnetic resonance tomography, multimodal evoked potentials and cerebrospinal fluid examination in multiple sclerosis]

Seventy patients with multiple sclerosis (according to Poser's criteria) were clinically assessed and examined with MRI, multimodal evoked potentials (VEP, AEP, SSEP) and CSF analysis (transformed lymphocytes, IgG-Index, oligoclonal banding). In relation to the clinical criteria of McAlpine 40 patients had possible, 16 patients probable and 14 patients definite MS. 81% of the patients (73% possible MS, 94% probable MS, 93% definite MS) had multiple white matter lesions detected by MRI, 79% (78% possible MS, 94% probable MS, 64% definite MS) had an abnormal CSF profile and 67% (60% possible MS, 75% probable MS, 79% definite MS) abnormal results in multimodal EP testing. Of the patients who experienced only one attack (n = 40) 78% had multiple lesions on MRI, 88% had abnormal CSF-findings and 60% had pathologic EPs. Patients with two or more attacks showed in 87% multiple lesions on MRI, in 77% abnormal EPs and in 70% abnormal CSF findings. The number of abnormal MRI and EPs increases with the duration of the disease. 13 patients with a normal MRI were discussed separately. MRI is the most sensitive method in detecting the spatial pattern of disseminated lesions. To monitor the dissemination over time a careful clinical follow-up is still mandatory.

Uncoupling of hexose transport and phosphorylation in human gliomas demonstrated by PET

Tumor uptake of [18F]2-fluoro-2-deoxy-glucose (FDG) was studied in 20 patients with histologically classified gliomas, using dynamic positron emission tomography (PET). Parametric images of local blood volume, glucose metabolic rate, transport and phosphorylation rate constants were generated by weighted non-linear least-squares fits on a pixel-by-pixel basis. Tumor metabolism, i.e. ratios of tumor peak metabolism to contralateral brain metabolism, corresponded with histological grade. Approximately half of the tumors showed considerable metabolic heterogeneity, and metabolically active areas were found in the periphery of seven tumors. Rate constants of FDG transport and phosphorylation were significantly correlated and were inversely coupled to plasma glucose levels in contralateral brain. In contrast, tumor transport and phosphorylation rate constants varied independently of each other and of plasma glucose concentration. In some tumors large alterations of FDG phosphorylation were observed in presence of nearly normal FDG transport.