Frequency distribution of the initial clinical manifestations
Investigating the early symptoms of the tumors as initial manifestations, headache was the most frequent symptom. Vomiting, ataxia and double vision were respectively indicated as the next most frequent symptoms after headache, as shown in more details in table 2. Table 3 demonstrates the frequency of initial tumor manifestations classified by tumor’s anatomical location. Therefore, headache, vomiting, ataxia and double vision have the highest frequency in infratentorial region while in supratentorial region, seizure, horizontal nystagmus and headache are respectively the most frequent symptoms.