Interpretation of the electroencephalogram.

The background pattern is described in terms of frequency and amplitude. Waves of varying frequencies may be normal or abnormal, depending on the patient's age and state of wakefulness. Specific features sought in the EEG are slowing of frequency, asymmetry of frequency or amplitude, paroxysmal disturbances, and spikes and sharp waves. Certain abnormalities may be present only after provocation by hyperventilation, sleep deprivation or induction, photic stimulation or drugs.

Cavernous hemangioma of optic chiasm, optic nerves and right optic tract. Case report and review of literature.

Diminishing right ocular visual acuity for three weeks in a 30 year old man was confirmed by examination. Bilateral scotomata and bitemporal hemiachromatopsia indicated a chiasmal lesion; reduced visual acuity and Marcus Gunn pupil of the right eye and left relative temporal hemianopia indicated asymmetric involvement. Erythrocytes in the CSF verified a suspected subarachnoid bleed; contrast-enhanced CAT scan demonstrated a suprasellar mass. A cystic, multiloculated, bluish mass distorted the right optic nerve, tract, and chiasm. A hematoma was evacuated and biopsy revealed a cavernous hemangioma of the right optic nerve. Post-operatively, visual acuity has recovered in the right eye but a left homonymous temporal hemianopia has developed.

Venous angioma of the optic chiasm.

A 30-year-old man presented with decreased vision in the right eye of three weeks' duration. Examination indicated a chiasmal syndrome and evidence of subarachnoid hemorrhage. CAT scan showed a large suprasellar mass. Surgical intervention confirmed the presence of a globular lesion filled with blood clots involving mainly the right side of the optic chiasm. Following removal of the clots, the chiasm regained its shape and anatomical landmarks. Biopsy of the mass demonstrated a venous angioma located within the optic chiasm as well as recent and old bleeding. Following surgery the patient did well and recovered vision in the right eye, though a left homonymous hemianopia persisted.

Parkinsonism and levodopa: a five-year experience.

Seventy parkinsonian patients were treated continuously with levodopa for five years. During the first year, sixty-three patients (90 per cent) improved. After five years, however, only thirty-seven patients remained improved while thirty-three patients (48 per cent) experienced progressive disease. Complications of treatment, albeit nonfatal, increased in frequency during the five-year interval. The reason for early improvement and subsequent deterioration of parkinsonian symptoms and signs in spite of levodopa therapy remains unexplained. It suggests that Parkinson's disease may not be simply a striatal dopamine deficiency syndrome and that treatment with levodopa is more than replacement therapy.

Abnormal brain scans in multiple sclerosis.

A 25 year old man, with a family history of multiple sclerosis in two preceding generations, developed transient sensory changes and incoordination, initially on the left side, and then several months later on the right side in association with an elevated CSF gamma globulin. This was followed by an acute optic neuritis. During the latter episode he developed a positive brain scan which was unaccompanied by any clinical findings explained by a lesion in that area. Cerebral arteriography was normal and the brain scan returned to normal four weeks later, possibly as a result of blood brain barrier restoration. Abnormal brain scans appear to occur only during acute exacerbations of demyelinating disease, and multiple sclerosis should be part of the differential diagnosis of a positive brain scan in a person in the appropriate age range.