Wireless networking is the fastest growing segment of the networking industry. Recent advancements in wireless networking enabled proliferation of wireless sensor networks. These sensor networks are capable of monitoring and controlling environments. These find several potential applications in medical industry and one of the most primary applications is Body Area Network (BAN). BAN has revolutionized the patient monitoring system. Nevertheless there are numerous challenges in the design of these systems, as they need to provide a right formation of network topology, reliable data delivery in a timely manner and consume less power. Topology formation is an important issue in a wireless sensor network. Performance parameters such as throughput, traffic sent, traffic received, packets dropped and sensor field coverage depend on the network topology is an important criterion to investigate. In this paper, we investigate the performance of WSN based on various topologies scenarios like: Cluster, Mesh and star. The whole study is performed by taking into account the specific features and recommendations of the IEEE 802.15.4/ZigBee standards; thus, our results can be used to configure IEEE 802.15.4/ZigBee procedures and set the related parameters, as a function of the desired application requirements.