MR vs CT in progressive supranuclear palsy.

Nine progressive supranuclear palsy (PSP) patients were studied with computerized tomography (CT) and magnetic resonance (MR) in order to determine the efficacy of each in detecting atrophy of the brainstem. Three additional PSP patients were evaluated with MRI for quantitative (electronic) measurements of the colliculi, pons and midbrain tegmentum. Both CT and MRI were equally effective in demonstrating midbrain atrophy. The MR was able to utilize the sagittal view to visualize thinning of the collicular (quadrigeminal) plate, a useful sign in PSP. Atrophy of the thinned collicular plate is more pronounced in the superior colliculus, one of the most common sites of pathology in PSP. The MR is able to make quantitative measurements of the degree of atrophy of the colliculi, pons and midbrain tegmentum.

CT brainstem abnormalities in the differential diagnosis of Huntington's disease.

Thin-section computed tomographic (CT) scans of 1.5 mm thickness were obtained in the study of 44 consecutive patients with Huntington's disease (HD) and six patients with sporadic progressive chorea and dementia. Mild to moderate midbrain and pontine atrophy, a dilated third ventricle, and enlarged quadrigeminal plate cisterns were observed in most cases suggesting that brainstem atrophy is common in HD. Brainstem atrophy preceding caudate atrophy in two cases and pontine or midbrain atrophy to a similar degree as caudate atrophy in eight cases suggest that brainstem atrophy may occasionally precede or appear at the same time as caudate atrophy. The CT scan brainstem findings and their neuropathologic confirmation suggests a more important role for the brainstem in the pathophysiology of HD.

Tremor in progressive supranuclear palsy.

Reports of tremor in progressive supranuclear palsy (PSP) have been infrequent; some authors indicate that tremor is never seen in PSP. Five patients with PSP and tremor are presented. Our series of cases and those reviewed in the literature suggest that tremor occurs in 12-16% of PSP cases. The rest tremor observed in 3 of our cases differed from the "pill-rolling" and "parkinsonian tremor" described in previously reported cases by being slower in rate (3 per second or less). This slow rest tremor is rarely seen in Parkinson's disease (4-6 per second). Our experience suggests that, contrary to previous opinions, tremor may be the presenting complaint and a prominent finding in PSP and the presence or absence of tremor is of no value in the differential diagnosis of PSP from Parkinson's disease.

Primidone/phenobarbital-induced periodic alternating nystagmus.

A 37-year-old man with a history of seizures developed periodic alternating nystagmus (PAN) along with other signs of primidone/phenobarbital toxicity. The PAN gradually diminished in cycle length and intensity, finally resolving with gradual discontinuation of the drugs.

Downbeat nystagmus secondary to multiple sclerosis.

Downbeat nystagmus has been associated with an increasing number of neurologic disorders, yet, it has only rarely been described in multiple sclerosis. Two patients with downbeat nystagmus secondary to multiple sclerosis are presented. In one, the nystagmus cleared completely in three weeks. In the other, it has persisted unchanged for 2 1/2 years.

Thin-section CT of midbrain abnormalities in progressive supranuclear palsy.

Thin-section computed tomographic (CT) scans of 3 and 1.5 mm thickness were obtained using the Philips Tomoscan 310 and General Electric 8800 CT/T scanners in the study of 10 consecutive patients with progressive supranuclear palsy (PSP) and 31 patients with other diseases. Marked midbrain and moderate pontine atrophy, a dilated third ventricle, and enlarged quadrigeminal plate cisterns were observed in all PSP cases. The aqueduct was dilated in several. In six of the PSP cases, there was a striking midbrain abnormality in the form of a low-density area extending from the interpeduncular cistern toward the aqueduct. Thin-section metrizamide-enhanced cisternography of three of the six PSP cases showed that the low-density abnormality was the result of the interpeduncular cistern invaginating the atrophic midbrain.

Ocular dipping.

In ocular dipping, a slow downward motion of the eyes is followed by a delay at the extreme of downgaze and terminated by a quick return to midposition. A 53-year-old man developed ocular dipping following prolonged hypotension. In contrast to previously described cases, we were unable to observe a delay phase in some cycles of dipping. Videotape analysis documented delays of 0.06 to 0.12 seconds in the cycles. At autopsy, there were hypoxic changes bilaterally in the cerebellum and hippocampi. Only one other such patient has been autopsied. This disorder has no localizing significance.

Myorhythmia: a widespread movement disorder. Clinicopathological correlations.

The clinical manifestations of 24 cases and the autopsy findings of 6 cases of extremity myorhythmia are presented. Extremity myorhythmia is that form of myorhythmia in which rhythmic alternating movements predominantly involve the limbs. The main difference between the tremor of extremity myorhythmia and the tremor of parkinsonism is the slower tremor rate, 2 to 3 cycles/s in myorhythmia and 4 to 6 cycles/s in parkinsonism. The mechanograms, except for the slower frequencies in myorhythmia, can be very similar, including sinusoidal oscillation patterns in both conditions. Myorhythmia may be defined as a coarse, alternating tremor, present at rest and usually during movement, which occurs at rates varying from 50 to 240 oscillations/min but mostly at either 120 to 140 or 160 to 180 cycles/min. The alternating movements may be intermittent or continuous or both types may be present in different body parts. When multiple parts are involved, synchronous or asynchronous movements are about equally common. Movements are usually relatively rhythmic and regular but may vary over periods of time in rate, rhythm or amplitude and rarely so, even over the course of a few hours and are absent during sleep. Movements may involve single limbs, several limbs or a combination of limbs plus face, palate, head, jaw, neck, tongue, eyes or trunk. The frequency of the movements in the 24 cases varied from 120 to 180 oscillations/min with two exceptions the slowest being 60 and the fastest 240, with most tending to cluster near either 120 or 180 cycles/min. The most common aetiologies were brainstem vascular disease and cerebellar degeneration secondary to chronic alcoholism-nutritional deficiency. The best prognosis occurred in the latter group. Clinicopathological correlations in our autopsy series indicate that myorhythmia of the limbs may occur ipsilateral to the dentate nucleus or superior cerebellar peduncle lesions or contralateral to inferior olive involvement. Unilateral lesions of the dentate nucleus may result in bilateral limb movements and bilateral dentate lesions may be associated with unilateral limb movements. The frequent involvement of the cerebellum and the substantia nigra suggests possible roles for the cerebellum and substantia nigra in the myorhythmia process.

Cerebral mucormycosis (Phycomycosis) in a heroin addict.

Cerebral mucormycosis was found at autopsy in a 27-year-old male narcotic addict with rapidly progressive focal neurologic signs. There was no evidence of rhinocerebral involvement of systemic illness, and a nuclide brain scan suggested brain abscess.

The evolution of a brain abscess the complementary roles of radionuclide (RN) and computed tomography (CT) scans.

Serial Tc-99m glucoheptonate brain scans demonstrated a brain abscess in a patient from the earliest phase of acute focal encephalitis (cerebritis) through the capsule formation and the recovery phase. The role of the RN and CT scans in the diagnosis of the early stage of cerebritis and the complementary nature of RN and CT scans in intracranial infections, particularly abscesses, are discussed. Guidelines for the use of RN and CT scans are suggested.

Periodic alternating ping-pong gaze.

A patient had periodic alternating Ping-Pong gaze and massive bilateral ischemic cerebral infarction proved at autopsy. In previous cases, bilateral hemisphere involvement appears to have been common in most cases. Eye movements in Ping-Pong gaze are similar to the slow-eye movements seen in sleep, anesthesia, and other obtunded states, a result of disinhibition of inherent rhythms in the oculovestibular system. They are like release phenomena and appear whenever fixational ability is lost or suspended, and during full consciousness they are inhibited by supranuclear cortical mechanisms. Ping-Pong gaze represents a distinct third variety of periodic alternating gaze disturbance, and the differential diagnostic features between it and periodic alternating gaze deviation and periodic alternating nystagmus are discussed.