In hemi-prosopometamorphopsia (hemi-PMO), features on one side of the face are distorted while features on the other side of the face look normal (Grusser et al., 1991, Cho et al., 2011, Almeida et al., 2020). Patient A.D. who we reported on in Almeida et al. (2020) often saw features on the right side of the face as if they were melting, but he did not see distortions on the left side of faces or in any other objects or body parts. When faces were turned upside down, the distortions continued to affect the same features they affected in upright faces. See figure below illustrating how A.D. might have seen the same photo when it was upright and upside down (the distorted part of the faces are shaded red to highlight them). However, in other cases (Nagaishi et al., 2015), the features that are distorted appear to change when faces are rotated.

Figure: The area in red shows where a PMO participant we worked with saw distortions when we showed him upright and upside-down faces (Almeida et al.,2020).


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