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Biomedical subjects

Frank Tong

Publications and source records attributed to Frank Tong.

4 recordsLinked to original sources

Cerebral Venous Thrombosis.

Because of its wide range of presentations, its highly variable mode of onset, its numerous causes, and its unpredictable outcome, cerebral venous thrombosis (CVT) remains a diagnostic and therapeutic challenge. Treatment of CVT consists primarily of symptomatic treatment of seizures and intracranial hypertension, antithrombotics, and etiologic treatment whenever possible. Heparin remains the first line of treatment for CVT; although its systematic use remains debated, recent studies have confirmed its safety even in patients with large hemorrhagic infarctions. The addition of local thrombolysis is indicated for patients with clinical worsening related to extension of the venous thrombosis, despite adequate anticoagulation and optimal symptomatic and etiologic treatment. In contrast to arterial stroke, complete recovery of prolonged or severe neurologic deficit is possible, justifying initiation of anticoagulation and eventually thrombolysis, even when the clinical situation seems desperate. New techniques using mechanical devices disrupting the clot may be used in addition to thrombolysis in rare cases. Ventricular drainage is indicated in cases of cerebellar infarction or deep venous thrombosis associated with hydrocephalus. Decompressive craniotomy may be performed acutely in patients with untractable intracranial hypertension and herniation.

Journal Article↗

Cerebral Venous Thrombosis.

Because of its wide range of presentations, its highly variable mode of onset, its numerous causes, and its unpredictable outcome, cerebral venous thrombosis (CVT) remains a diagnostic and therapeutic challenge. Treatment of CVT consists primarily of symptomatic treatment of seizures and intracranial hypertension, antithrombotics, and etiologic treatment whenever possible. Heparin remains the first line of treatment for CVT; although its systematic use remains debated, recent studies have confirmed its safety even in patients with large hemorrhagic infarctions. The addition of local thrombolysis is indicated for patients with clinical worsening related to extension of the venous thrombosis, despite adequate anticoagulation and optimal symptomatic and etiologic treatment. In contrast to arterial stroke, complete recovery of prolonged or severe neurologic deficit is possible, justifying initiation of anticoagulation and eventually thrombolysis, even when the clinical situation seems desperate. New techniques using mechanical devices disrupting the clot may be used in addition to thrombolysis in rare cases. Ventricular drainage is indicated in cases of cerebellar infarction or deep venous thrombosis associated with hydrocephalus. Decompressive craniotomy may be performed acutely in patients with untractable intracranial hypertension and herniation.

Journal Article↗

Out-of-body experiences: from Penfield to present.

Can the brain, when stimulated, yield entirely novel experiences? Blanke et al. (2002) describe a patient who reported spontaneous out-of-body experiences during electrical stimulation of her angular gyrus. These findings, although apparently extraordinary, agree with much earlier reports from a patient tested by Wilder Penfield. Such studies can provide clues about the nature of conscious experience.

Journal Article↗

Primary visual cortex and visual awareness.

The primary visual cortex (V1) is probably the best characterized area of primate cortex, but whether this region contributes directly to conscious visual experience is controversial. Early neurophysiological and neuroimaging studies found that visual awareness was best correlated with neural activity in extrastriate visual areas, but recent studies have found similarly powerful effects in V1. Lesion and inactivation studies have provided further evidence that V1 might be necessary for conscious perception. Whereas hierarchical models propose that damage to V1 simply disrupts the flow of information to extrastriate areas that are crucial for awareness, interactive models propose that recurrent connections between V1 and higher areas form functional circuits that support awareness. Further investigation into V1 and its interactions with higher areas might uncover fundamental aspects of the neural basis of visual awareness.

Animals↗