Atrophy of one side of the papilla and edema of the other side are usually seen in tumors or abscesses at the base of the frontal lobe of the brain, such as internal carotid artery aneurysms, olfactory groove meningiomas, meningiomas at the base of the skull in the anterior cranial recess, and craniopharyngioma. Other tumors such as internal carotid artery spindle dilation, internal carotid artery sclerosis, trauma to the anterior cranial sulcus, arachnoiditis of the anterior cranial sulcus may also cause atrophy of the optic papilla on one side and edema on the other side. As one side of the optic nerve is directly compressed by the tumor and atrophied first, later on the tumor continues to grow and increases the intracranial pressure, resulting in edema of the healthy side of the optic papilla. The ipsilateral frontal lobe tumor can lead to primary optic nerve atrophy and edema of the contralateral optic disc, which is known as Foster Kennedy syndrome. Foster-Kennedy syndrome is a symptom of frontal lobe tumor. What are the examination methods of frontal lobe tumor? 1.Cranial plain film Cranial plain examination can make localization or qualitative diagnosis for some frontal lobe tumors, such as oligodendroglioma can sometimes appear calcified spots, which are characterized by cord-like, speck-like or mass-like, interlocking calcified spots; astrocytoma, calcification mostly occurs in the cystic wall or tumor body of the tumor, and the calcified shadow is mostly arc-shaped, cord-like, sheet-like or speck-like; ventricular meningioma is usually found in the lateral ventricle, and commonly has speck-like Ventricular meningioma is more likely to be found in the lateral ventricles and often has speckled calcifications. Calcifications of meningiomas tend to appear as large masses with high density and clear contours, with sand-grain meningioma calcifications being the most common. Frontal lobe glioma, meningioma and metastases can cause cranial resorption, thinning, destruction and defect when they are close to the skull, and meningioma is also commonly associated with cranial hyperplasia. When frontal lobe tumor causes increase of cranial pressure, it can be seen that there is an increase of cerebral gyrus pressure, cranial suture splitting, change of bone shape and displacement in the pterygoid saddle. 2.Internal carotid arteriogram In frontal lobe tumor, it mainly leads to the superior segment of the internal carotid artery, the anterior 2/3 of the anterior cerebral artery and the beginning of the middle artery. In frontal lobe tumor, it mainly leads to displacement and deformation of vessels in different directions and degrees with frontoparietal ascending artery. 3.Ultrasound During the ultrasound examination of frontal lobe tumor, the midline wave can be seen to have moderate displacement to the healthy side. In frontal pole, frontal floor tumor and double frontal tumor, the midline wave is not shifted, but different degrees of tumor pathology wave may appear. If the tumor compresses the foramen ovale and causes obstructive hydrocephalus, it can show that the amplitude of ventricular wave increases and the distance between lateral ventricular wave and midline wave becomes larger, so the degree of hydrocephalus can be inferred. 4.EEG Frontal lobe tumor EEG examination performance has the following characteristics: (1) the appearance rate of limited δ waves is higher about 83%; (2) 40% of them present unilateral or bilateral paroxysmal single rhythmical δ waves, especially more tumors in the medial frontal lobe or basal plane; (3) about 1/3 of unilateral frontal lobe tumors also have propagating δ waves in the contralateral frontal part, but generally the wave amplitude is low and often becomes mixed δ waves of background α waves, in 1/3 of cases, show normal, and generally, the more anterior the tumor location is, the lighter the α abnormality is; (4) bilateral frontal lobe tumors, characterized by mutually independent polymorphic δ waves in bilateral frontal areas, the side with larger tumors is more obvious. The θ waves and lazy waves appear in a wider range. 5.Brain CT examination CT mainly diagnoses intracranial tumor through density contrast of tumor and surrounding tissues and displacement and deformation of normal structures (such as ventricles). Frontal lobe tumors are commonly gliomas and meningiomas, which generally show higher density; the anterior horn of the lateral ventricle is commonly deformed by compression.