Previous studies have found that deaf signers exhibited lower accuracy when recognizing emotional expressions from top-half faces compared to hearing non-signers. This suggests that the lack of emotional information from the oral region has a greater impact on deaf signers due to differences in their gaze patterns. The current study aimed to replicate and extend these findings by measuring recognition accuracy under varied facial conditions and analyzing late positive potential (LPP) amplitudes. Based on previous research, it was hypothesized that deaf signers would show reduced recognition accuracy and lower LPP amplitude compared to hearing non-signers in a top-half face condition. To test these hypotheses, 22 deaf signers and 37 hearing non-signers made emotion judgments of faces presented as intact wholes or isolated top or bottom halves, while event-related potentials were recorded. The results supported the main hypotheses, showing that the deaf signers exhibited lower recognition accuracy and reduced LPP amplitudes in the top-half face condition compared to hearing non-signers. These findings were discussed in terms of the challenges deaf signers faced during the COVID-19 pandemic, particularly in contexts where facial masks obscured the mouth.