A study of low frequency noise is made in Solid Phase Crystallised (SPC) polysilicon Thin Film Transistors (TFTs) issued from low temperature process (≤600° C). The study is performed in both below and above threshold regions. At first, a static electrical caracterisation of the transistors is carried out. Analysis of the low frequency noise in the TFTs shows that it can be related both to the Meyer-Neldel MN effect, and to the flatband voltage fluctuations due to the trapping/detrapping processes of carriers at the SiO2/Poly-Si interface. Furthermore, a new method of the channel carrier number calculation is proposed. Then, the apparent noise parameter αapp, based on the Hooge formula, is deduced. At low gate voltages αapp increases and reaches a maximum value close to the threshold voltage. This αapp singular behavior is then discussed.