Neuropsychological features of PPA variants
| PPA-G | The central feature is an abnormality of syntax (word-order) or some other aspect of grammar in spoken or written language in the presence of relatively preserved single word comprehension. Fluency is often impaired. |
| PPA-S | The central feature is an abnormality of single word comprehension in the presence of relatively preserved grammar and fluency. Output is circumlocutory, occasionally uninformative and frequently paraphasic. Naming is severely impaired. |
| PPA-L | The central feature is intermittent word-finding hesitations and phonemic paraphasias. Naming is impaired but not as severely as in PPA-S and improves upon phonemic cueing. |