This study investigated the hypothesis that the combination of regional CT brain atrophy measurements and semiquantitative SPECT regional blood flow ratios could produce a diagnostic test for Alzheimer's disease (AD) with an accuracy comparable to that achieved with the present clinical gold standard of the NINCDS-ADRDA criteria.

Single proton emission computed tomography (SPECT) and CT head scans were performed on 122 subjects referred an UBC Alzheimer clinic and diagnosed as either ‘not demented’ (ND-37) or ‘possible/probable AD’ (AD-85) by the NINCDS-ADRDA criteria. Stepwise discriminant analysis (SDA) was performed on the bilateral SPECT regions of interest and compared to bilateral CT qualitative/quantitative assessment in the frontal, parietal and temporal lobes to determine which were most accurate at ND/AD distinction. Receiver operating curves (ROC) were then constructed for these variables individually and for their combined discriminant function.

The left temporal qualitative cortical atrophy score (CT) and left temporal perfusion ratio (SPECT) were selected in the SDA. The combined discriminant function was more specific at AD/ND distinction than either of CT or SPECT alone. The accuracy of AD/ND distinction with the combined discriminant function was below that achieved by clinical diagnosis according to the NINCDS-ADRDA criteria and was not significantly different from that achieved with SPECT or CT alone as defined by ROC curve analysis.

The measurements of left temporal cortical atrophy and regional cerebral blood flow were most indicative of AD; however they lacked the sensitivity and specificity to recommend their use as a diagnostic test for AD.

To utilize the diagnostic criteria of frontal lobe dementia (FLD).

We studied 12 patients with FLD diagnosed clinically, with radiological confirmation in 10 and autopsy confirmation in 2; sixteen patients with Alzheimer's disease matched for stage and severity to FLD and 11 patients with depressive dementia were used as control groups. A 24-item Frontal Behavioral Inventory (FBI) using the most relevant behavioral manifestations of FLD was administered in these populations.

FLD patient scores on the FBI were much higher compared with control groups (AD and DD). Item analysis showed loss of insight, indifference, distractibility, personal neglect and apathy as the most frequent negative symptoms. Perseveration, disinhibition, inappropriateness, impulsivity, and irresponsibility were the most significant positive symptoms. An operational definition of FLD included a minimum FBI score of 27. Only one false positive was shown in the depressive group and none among the AD group, indicating little overlap between patient groups, and a high discriminating value of the FBI.

The FBI appears to be a useful diagnostic instrument and a method to operate the behavioral criteria of FLD. Further prospective studies are warranted to establish validity.

Alfentanil is a potent, short-acting opioid agent which has been used during balanced anaesthesia in children undergoing the surgical excision of epileptic foci. After the observation that this agent had the potential to induce epileptic seizures, we questioned the frequency of this occurrence in this group of patients.

Twelve patients (6 males, 6 females) undergoing surgical excision of an epileptic foci were prospectively followed. For each patient an electrocorticogram was recorded for 30 minutes before and after receiving alfentanil 20 pg/kg intravenously. The frequency of epileptiform abnormalities before and after drug administration was evaluated. When the electrocorticogram no longer showed the effects of alfentanil administration, methohexital 0.5 ug/kg was given intravenously.

Alfentanil induced significant activation of epileptiform discharges among 83% of these patients. Twenty-five per cent had an electrographic seizure. In comparison, methohexital induced significant activation of epileptiform discharges in 50% of these patients. None experienced electrographic seizures.

As alfentanil can induce electrographic seizures in patients known to have epilepsy, caution is advised in its use in this group of patients.

We studied the incidence and clinical significance of early post-traumatic seizures after severe closed head injury.

This prospective study is based on clinical observation of 3340 adult patients with severe closed head injuries, each of them having a Glasgow Coma Scale (GCS) 3 to 8 after trauma. Anticonvulsant agents were not given to these patients unless there was evidence of seizure.

One hundred and twenty-one patients (3.6%) experienced seizures within 1 week after head injury; 42 of these (1.26% of the series) had seizures within 24 hours after trauma. The incidence of intracerebral parenchymal damage was found to be higher among those patients who developed seizures in the first week (66.1%) than in those who did not (62.7%). However this result did not reach statistical significance. The patients with early seizures had a lower mortality rate (p < 0.01). In patients who survived from the initial injury, the occurrence of early post-traumatic seizures did not appear to influence the neurological recovery at 6 months after injury.

Presence of intracerebral parenchymal damage on CT scan after severe closed head injury does not increase the risk of early post-traumatic seizures. With proper treatment, patients presenting with early seizures may have a lower mortality rate. However, the occurrence of early seizures does not influence the neurological recovery in patients who survive the initial severe closed head injury.

Previous studies demonstrated that destabilizing responses to slow perturbations were enhanced in patients with Parkinson's disease (PD). Our objectives were to investigate the influence of PD on responses to faster whole head-and-body tilts in the standing position, and to establish whether any modification of tilt-evoked responses in PD patients was related to possible changes in the modulation of soleus (SO) H-reflex.

Ten PD patients and 10 age-matched normal subjects assumed a standing position on an L-shaped tilting apparatus. Their head and shoulders were firmly attached to the back support of the apparatus, while their feet were fixated to the standing platform. With their vision occluded, the subject's whole head-and-body was suddenly tilted forward to 20°, at a peak head acceleration of 0.7g ± 0.lg. Tilt-evoked responses were recorded from the lower limb muscles bilaterally. In addition, 40 H-reflexes were elicited in the SO muscle at 30-190 ms intervals after the onset of head acceleration. The M response amplitude was kept within ±15% of its control value.

PD patients demonstrated an abnormally high responsiveness to whole head-and-body tilts in comparison with age-matched normal subjects. This was shown by the significantly larger proportion of PD patients manifesting responses in the SO, biceps femoris and vastus lateralis muscles (p<0.05), as well as their significantly larger SO response area (413%; p<0.01). In contrast, the amplitude of the SO H-reflex was significantly increased by only 14% (p<0.05) in these patients, and only at 30-70 ms after head acceleration onset.

The overexcitable tilt-evoked responses of PD patients could originate from a reduced ability to suppress responses when the body is supported. This enhanced excitability of tilt-evoked responses was probably not due to motoneuronal hyperexcitability or decreased presynaptic inhibition of the group la terminals involved in the mainly monosynaptic H-reflex pathway. Thus, we hypothesize that the control of spinal interneurons involved in the tilt-evoked responses may be defective in PD.

Observation of physiological changes during motion sickness is required to quantify the degree of sickness. The review of the literature does not show unifying results. An objective symptom of motion sickness is facial pallor. It reflects changes in skin microcirculation which have not been measured so far.

Eleven healthy volunteers susceptible to motion sickness were subjected to eccentric vertical axis rotation. The dynamics and the correspondence of the changes in skin blood flow in two segments, forehead and finger, were measured by laser Doppler flowmeter.

The difference in the microcirculatory skin blood flow across the phases of motion sickness is significant for the forehead but not for the fingertip; the established dynamics of the forehead blood flow during motion sickness will be of benefit in quantifying the degree of sickness; there is no correlation between the blood flow changes in both measured areas; the rhythmic blood flow fluctuation increases during motion sickness; there is a difference between the blood flow responses to vestibular stimulation before the appearance of motion sickness and in the course of the sickness. Laser Doppler flowmetry is a reliable method in quantifying the degree of motion sickness.

Difficulty recalling people's names is common in the adult population, especially in the elderly. The subject is scarcely mentioned in the literature. An 82-year-old patient gave the history that for 33 years he had made prospective observations on his own difficulty with people's names.

Documentation and analysis of the patient's personal observations in which his ability to recall the names of friends, acquaintances, colleagues, public figures, movie stars and athletes is compared with that of his spouse. A suitable test-battery for the names of famous North American persons was not available.

The patient's capability in recalling people's names was clearly inferior to that of his spouse. The patient's intellect was otherwise intact and the impairment seemed to be isolated to the category of proper-naming. Doubts were raised about the patient's own conclusion that the deficit was progressive.

A parallel may be drawn between benign difficulty recalling people's names and the acquired categorical deficit for proper naming reported in the literature in recent years. Based on Damasio's concept of anatomically compartmentalized sensory subsystems, it is hypothesized that our patient's symptom represents an innate limited capacity for proper naming.

Transtentorial herniation of large cerebral fragments is a rare phenomenon.

Case Study

Examination of the brain of a 35-year-old male showed massive intracerebral hemorrhage resulting in displacement of basal ganglia components into the fourth ventricle.

Sufficiently rapid intracerebral bleeding can dissect fragments of cerebrum and displace them long distances across the tentorial opening.

Pituitary dysfunction caused by intracranial aneurysms is rare. We report a patient with the unique feature of hyperprolactinemia to a degree previously seen only with prolactinsecreting tumours.

Case report.

A 42-year-old woman had a galactorrhea, left-sided headache, reduced vision in the left eye and a left temporal hemianopsia. Serum prolactin was elevated (365 μg/L). Cranial computed tomography (CT) revealed a suprasellar mass, which carotid angiography showed to be a left internal carotid artery aneurysm. At craniotomy, this aneurysm and a smaller one of the ophthalmic artery were repaired, and the patient's vision returned to normal. The prolactin level fell to normal. Follow-up CT showed no evidence of pituitary adenoma or hypothalamic lesion.

Carotid aneurysm can cause reversible pituitary dysfunction. A prolactin level >300 μg/L is not a reliable cut-off for distinguishing prolactin-secreting adenomas from other causes of elevated prolactin. A co-existing prolactinoma was felt to be ruled out by both a normal CT scan and normal prolactin levels following aneurysm repair. Patients with marked hyperprolactinemia should be considered for angiography or MRI to rule out carotid aneurysm, since the consequences of pituitary exploration in this setting are potentially grave.

Lumbosacral plexopathy is a complication of diabetes mellitus. Conn's syndrome from an aldosterone secreting adenoma may be associated with hypokalemia and rhabdomyolysis but mild hyperglycemia also usually occurs.

Case description.

A 70-year-old male diagnosed as having Conn's syndrome, hypokalemia and mild hyperglycemia developed rhabdomyolysis and lumbar plexopathy as a presenting feature of his hyperaldosteronism. His rhadbdomyolysis rapidly cleared following correction of hypokalemia but recovery from the plexopathy occurred slowly over several months. Definite resection of the aldosterone secreting adenomas reversed the hyperglycemia.

Our patient developed lumbar plexopathy resembling that associated with diabetes mellitus despite the presence of only mild and transient hyperglycemia.

Complex auditory hallucinations have rarely been reported in cases of brainstem stroke or tumor.

Case study.

A patient with acute Listeria rhombencephalitis complained of formed musical auditory hallucinations on the side of recent sensorineural deafness. MRI revealed an abscess in the middle cerebellar peduncule with extensive surrounding edema.

Disruption of brainstem auditory pathways may cause complex auditory hallucinations. Potential pathogenetic mechanisms are discussed and a diagnostic approach is proposed.

Tuberculosis of the nervous system has protean manifestations. Syringomyelia, though an uncommon complication of it, is usually of late onset.

We report two patients with tuberculosis meningitis who developed syringomyelia acutely. The diagnosis was supported by neuroimaging and findings at laminectomy.

The two patients developed syringomyelia between 11 days and 6 weeks of the onset of tuberculous meningitis. They both had cord swelling and softening

Acute-onset syringomyelia should be suspected in any patient being treated for tuberculosis meningitis who subsequently develops limb weakness and/or sphincteric dysfunction. Inflammatory edema and cord ischemia appeared to be the underlying mechanisms in these early onset cases rather than arachnoiditis which is important in late-onset cases.

Peripheral nerve injury at the wrist following Colles' fracture is rare and usually located in the region of the fracture. Mononeuropathies in the proximal forearm have not been reported.

We present two patients with Colles' fracture with proximal forearm neuropathies.

Both cases were associated with mononeuropathies in the forearm as proximal as the elbow, involving the median, ulnar and radial nerves in one, and the median and ulnar nerves in the other.

Following Colles' fracture proximal nerve involvement may occur and, with increased awareness, this lesion may be identified more frequently.