Gary Libben & Michel Paradis 
The Assessment of Bilingual Aphasia [PDF ebook] 

The
Bilingual Aphasia Test is a comprehensive language test designed to assess the differential loss or sparing of various language functions in previously bilingual individuals. The individual is tested, separately, in each language he or she previously used, and then in the two languages simultaneously. The testing is multimodal — sampling hearing, speaking, reading, and writing; and multidimensional — testing various linguistic levels (phonological, morphological, syntactic, lexical, and semantic), tasks (comprehension, repetition, judgment, lexical access and propositionizing), and units (words, sentences, and paragraphs).  The BAT is structured as follows:
* To test a bilingual aphasic, you will need the following testing elements: the stimulus books for each of the languages in which the individual was formerly fluent, the single-language tests for each of these languages, as well as the bilingual test that links them. For example, if you are testing an English-French bilingual aphasic, you will need an English stimulus book, a French stimulus book, an English single-language test, a French single-language test, and an English-French bilingual test.
* The BAT can also be used to test monolingual aphasics. To test for monolingual aphasia, you will need the stimulus book and the single-language test in the language in which the individual was formerly fluent.
* Professor Paradis» book,
The Assessment of Bilingual Aphasia, provides the background material and serves as the manual for the test.
The BAT is available in dozens of languages and language pairs. There are now 106 bilingual pairs available. Additional single-language and bilingual tests are being prepared continuously. If the language (or language pair) you need is not listed, please call LEA to find out if and when it will be available.