The purpose of this study is to determine whether VR based language rehabilitation scenario based on the core premises of ILAT has a beneficial effect on the linguistic performance (faster retrieval of the target lexicon and general fluency) of Broca's aphasia patients. Furthermore, it aims at testing the effects of cueing (visual and auditory) on word retrieval.

Acquired brain lesions such as stroke often result the most common disabling neurological damages (Carter et al, 2012). 35-40% of stroke patients suffer serious language deficits and patients are frequently left with chronic disabilities which adversely impact their quality of life. Thus, the need for efficient rehabilitation methods increases. Recent studies show that Broca's area and the premotor cortex are anatomically coupled (Pulvermuller 2005) suggesting that for a therapy to be effective, in the brain there must be an interaction between linguistic neural system, motor and sensory circuits, memory, planning and monitoring (Kurland et al, 2012). These hypotheses led to the establishment of the so-called Intensive Language-Action Therapy (ILAT) (Pulvermuller 2012) which promotes motor movement during language practice. Thus, ILAT is an action-embedded language therapy grounded in three main principles: intense practice, overcoming learned non-use, and promoting motor actions (no compensations). Recently, a number of studies examined the functionality of virtual reality based rehabilitation systems that aim at post stroke motor recovery of upper extremities (Boian et al., 2002; Cameirão, Badia, Oller, & Verschure, 2010; Jack et al., 2001; Saposnik et al., 2010). In the present study, the goal is to further validate VR based language rehabilitation system based on the core principles of ILAT implemented within the environment of the rehabilitation Gaming System (RGS). Additionally, the goal is to investigate the effects of cueing on word retrieval. It was shown that conduction and Broca's aphasics exhibit the highest responsiveness to cueing (Li & Williams 1989). In order to overcome subsequent disturbances in word retrieval mechanisms, a number of cueing methods have been established to improve both the immediate and long term lexical access (Howard 2000). Both semantic and phonemic cues act as primes and are usually administered by the therapist in a written or oral manner containing phonological, semantic or syntactic information about the target word (Howard et al. 1985, Howard2000). Here, the investigators will implement the system with videos representing the lip motion representative for a correct pronunciation of the target words, as well as a representative sound (i.e. barking sound in case of dog). The investigators expect that the proposed system will be efficient in treating post stroke chronic Broca's aphasia patients according to the standard scales such as Boston Naming Test and Communicative Activity Log.

Inclusion Criteria:

• Broca's aphasia patient following ischemic and hemorrhagic strokes (moderate and chronic stages).
• Mild, moderate and chronic Broca's stages.
• Age: between 25 and 85 years old.
• Absence of any major cognitive impairments (MMSE>25).

Exclusion Criteria:

• Presence of major perceptual, motor and neuropsychological impairments that make it difficult to interact with the system, including severe forms of motor impairments and apraxia, visual processing deficits, planning deficits, learning deficits, memory deficits, or attentional deficits.