Here is a list of references to ongoing projects in language attrition. Should you know about a project which is not included here, please let me know.
Monika S. Schmid, University of Groningen/University of Essex:
NWO Open Competition project: The impact of age and exposure on forgetting and retention of the birth language in international adoptees: a perspective from Holocaust survivors
Monika S. Schmid, University of Groningen/University of Essex:
VICI-project The age effect in bilingual development: grammatical gender in second language acquisition and first language attrition (2010 – 2015)
Summary—Full project description
Kristina Kasparian/Karsten Steinhauer, McGill University
The case of the non-native-like first language: Neurophysiological studies of first-language attrition
Language Attrition 