Conversational Therapy through Semi-Immersive Virtual Reality Environments for Language Recovery and Psychological Well-Being in Post Stroke Aphasia.

Aphasia is a highly disabling acquired language disorder generally caused by a left-lateralized brain damage. Even if traditional therapies have been shown to induce an adequate clinical improvement, a large percentage of patients are left with some degree of language impairments. Therefore, new approaches to common speech therapies are urgently needed in order to maximize the recovery from aphasia. The recent application of virtual reality (VR) to aphasia rehabilitation has already evidenced its usefulness in promoting a more pragmatically oriented treatment than conventional therapies (CT). In the present study, thirty-six chronic persons with aphasia (PWA) were randomly assigned to two groups. The VR group underwent conversational therapy during VR everyday life setting observation, while the control group was trained in a conventional setting without VR support. All patients were extensively tested through a neuropsychological battery which included not only measures for language skills and communication efficacy but also self-esteem and quality of life questionnairies. All patients were trained through a conversational approach by a speech therapist twice a week for six months (total 48 sessions). After the treatment, no significant differences among groups were found in the different measures. However, the amount of improvement in the different areas was distributed over far more cognitive and psychological aspects in the VR group than in the control group. Indeed, the within-group comparisons showed a significant enhancement in different language tasks (i.e., oral comprehension, repetition, and written language) only in the VR group. Significant gains, after the treatment, were also found, in the VR group, in different psychological dimensions (i.e., self-esteem and emotional and mood state). Given the importance of these aspects for aphasia recovery, we believe that our results add to previous evidence which points to the ecological validity and feasibility of VR treatment for language recovery and psychosocial well-being.

Looking at ancillary systems for verb recovery: Evidence from non-invasive brain stimulation.

Several behavioural and neuroimaging studies have suggested that the language function is not restricted into the left areas but it involves regions not predicted by the classical language model. Accordingly, the Embodied Cognition theory postulates a close interaction between the language and the motor system. Indeed, it has been shown that non-invasive brain stimulation (NIBS) is effective for language recovery also when applied over sensorimotor regions, such as the motor cortex, the cerebellum and the spinal cord. We will review a series of NIBS studies in post-stroke aphasic people aimed to assess the impact of NIBS on verb recovery. We first present results which, following the classical assumption of the Broca's area as the key region for verb processing, have shown that the modulation over this area is efficacious for verb improvement. Then, we will present experiments which, according to Embodied Cognition, have directly investigated through NIBS the role of different sensorimotor regions in enhancing verb production. Since verbs play a crucial role for sentence construction which are most often impaired in the aphasic population, we believe that these results have important clinical implications. Indeed, they address the possibility that different structures might support verb processing.

Regulatory Considerations for the Clinical and Research Use of Transcranial Direct Current Stimulation (tDCS): review and recommendations from an expert panel.

The field of transcranial electrical stimulation (tES) has experienced significant growth in the past 15 years. One of the tES techniques leading this increased interest is transcranial direct current stimulation (tDCS). Significant research efforts have been devoted to determining the clinical potential of tDCS in humans. Despite the promising results obtained with tDCS in basic and clinical neuroscience, further progress has been impeded by a lack of clarity on international regulatory pathways. We therefore convened a group of research and clinician experts on tDCS to review the research and clinical use of tDCS. In this report, we review the regulatory status of tDCS, and we summarize the results according to research, off-label and compassionate use of tDCS in the following countries: Australia, Brazil, France, Germany, India, Iran, Italy, Portugal, South Korea, Taiwan and United States. Research use, off label treatment and compassionate use of tDCS are employed in most of the countries reviewed in this study. It is critical that a global or local effort is organized to pursue definite evidence to either approve and regulate or restrict the use of tDCS in clinical practice on the basis of adequate randomized controlled treatment trials.

"If two witches would watch two watches, which witch would watch which watch?" tDCS over the left frontal region modulates tongue twister repetition in healthy subjects.

Recent studies have demonstrated that transcranial direct current stimulation (tDCS) modulates cortical activity in the human brain. In the language domain, it has already been shown that during a naming task tDCS reduces vocal reaction times in healthy individuals and speeds up the recovery process in left brain-damaged aphasic subjects. In this study, we wondered whether tDCS would influence the ability to articulate tongue twisters during a repetition task. Three groups of 10 healthy individuals were asked to repeat a list of tongue twisters in three different stimulation conditions: one group performed the task during anodal tDCS (atDCS) (20 min, 2 mA) over the left frontal region; a second group during cathodal tDCS delivered over the same region; and, in a third group, sham stimulation was applied. Accuracy and vocal reaction times in repeating each tongue twister before, during and 1h after the stimulation were recorded. Participants were more accurate and faster at repeating the stimuli during atDCS than at baseline, while cathodal tDCS significantly reduced their performance in terms of accuracy and reaction times. No significant differences were observed among the three time points during the sham condition. We believe that these data clearly confirm that the left frontal region is critically involved in the process of speech repetition. They are also in line with recent evidence suggesting that frontal tDCS might be used as a therapeutic tool in patients suffering from articulatory deficits.

Action observation as a useful approach for enhancing recovery of verb production: new evidence from aphasia.

BACKGROUNDS: Evidence exists that the observation of actions performed by others enhance word retrieval and can be used in aphasia rehabilitation to treat naming impairments. AIM: The aim of the present study was to assess to what extent action observation treatment may improve verb retrieval in chronic aphasics. DESIGN: This was an observational study. SETTING: Patients were recruited from the Neurorehabilitation Centre of Ancona Hospital. POPULATION: Six aphasic patients underwent an intensive language training to improve verb naming. METHODS: Language evaluation was carried out before and after the treatment. A rehabilitation therapy based on observation of actions was administered daily to each patient for two consecutive weeks. Four different rehabilitation procedures were adopted: 1) "observation of action performed by the examiner"; 2) "observation and then execution of action"; 3) "observation of videoclips of actions"; and, as a control condition; 4) "observation of action and execution of meaningless movement". RESULTS: In four participants, a significant improvement in verb retrieval was found for the three experimental procedures (χ² (3)=75.212, P<0.0001), with respect to the control condition. No significant improvement was observed in the two patients with severe deficits in verb semantics (χ² (3)=0.592, P=0.892). CONCLUSIONS: Action observation therapy may become a useful intervention strategy to promote verb retrieval in aphasic patients. CLINICAL REHABILITATION IMPACT: The observation of videoclips of actions may be an efficacious alternative approach to traditional rehabilitation programs for lexical deficits. This finding endorses the planning of innovative low-cost interventions in language rehabilitation.

Electrical stimulation over the left inferior frontal gyrus (IFG) determines long-term effects in the recovery of speech apraxia in three chronic aphasics.

A number of studies have shown that modulating cortical activity by means of transcranial direct current stimulation (tDCS) affects the performance of both healthy and brain-damaged subjects. In this study, we investigated the potential of tDCS for the recovery of apraxia of speech in 3 patients with stroke-induced aphasia. Over 2 weeks, three aphasic subjects participated in a randomized double-blinded experiment involving intensive language training for their articulatory difficulties in two tDCS conditions. Each subject participated in five consecutive daily sessions of anodic tDCS (20 min, 1 mA) and sham stimulation over the left inferior frontal gyrus (referred to as Broca's area) while they performed a repetition task. By the end of each week, a significant improvement was found in both conditions. However, all three subjects showed greater response accuracy in the anodic than in the sham condition. Moreover, results for transfer of treatment effects, although different across subjects, indicate a generalization of the recovery at the language test. Subjects 2 and 3 showed a significant improvement in oral production tasks, such as word repetition and reading, while Subjects 1 and 2 had an unexpected significant recovery in written naming and word writing under dictation tasks. At three follow-ups (1 week, 1 and 2 months after the end of treatment), response accuracy was still significantly better in the anodic than in sham condition, suggesting a long-term effect on the recovery of their articulatory gestures.

The role of argument structure in the production of nouns and verbs.

The study reports an investigation on the role of argument structure complexity in the production of nouns and verbs in three Italian agrammatic patients. The patients, all showing a clear noun/verb dissociation in the assessment tests, were requested to produce either nouns or verbs in a picture naming task. Four sets of words were selected to be produced in the naming task: non-argumental nouns (e.g., medaglia-medal), argumental nouns (e.g., pianto-crying), one-place argument verbs (e.g., dormire-to sleep), and two-place argument verbs (e.g., sparare-to shoot). The performance of the three patients was almost identical. All made reliably fewer errors in the production of non-argumental nouns than in the production of verbs, thus replicating with the new materials the initially observed dissociation. Moreover, they made fewer errors with one-place than with two-place argument verbs, and with non-argumental than with argumental nouns. Finally, in contrast with the previously observed noun/verb dissociation, when their ability to produce argumental nouns and verbs was compared, no reliable difference was found. The results indicate that argument complexity may affect the ability of agrammatic patients to produce words. It is argued that since argument complexity is necessarily associated with verbs and only rarely with nouns, unless special attention is paid, argument complexity effects are easily confounded with grammatical class effects, possibly leading to erroneous interpretations of patients' performance.

Acquisition of new "words" in normal subjects: a suggestion for the treatment of anomia.

The study explores the efficacy of three learning methods in normal controls. Thirty subjects, randomly assigned to the repetition, reading aloud, or orthographic cueing method, were asked to learn 30 new "words" (legal nonwords arbitrarily assigned to 30 different pictures); 30 further new "words" were used as controls. Number of trials to criterion was significantly lower, and number of words remembered at follow-up was significantly higher for the orthographic cueing method. Two aphasic patients with damage to the output lexicons were also rehabilitated with the same three methods. In both patients the orthographic cueing method was significantly more efficacious. The differences in learning efficacy of the three methods are discussed.

Linguistic and nonlinguistic priming in aphasia.

Studies of real-time processing in aphasia suggest that linguistic symptoms may be due to deficits in activation dynamics rather than loss of linguistic knowledge. To investigate the domain specificity of such processing deficits, we compared performance by Italian-speaking fluent aphasics, nonfluent aphasics, and normal controls in a linguistic priming task (grammatical gender) with their performance in a color-priming task that requires no verbal mediation. Normal or larger than normal color-priming effects were demonstrated in both aphasic groups. Gender priming did not reach significance in either group, even though the patients displayed above-chance sensitivity to gender class and gender agreement in their accuracy scores. The demonstration of spared gender knowledge despite impaired gender priming underscores the utility of on-line techniques in the study of aphasia. The demonstration of spared color priming suggests that priming deficits in aphasia are either (1) specific to speech and language or (2) specific only to those sensorimotor and attentional processes that language shares with other nonlinguistic systems.

The nature of the disorder underlying the inability to retrieve proper names.

Two patients with the syndrome of proper name anomia were investigated. Both patients were only able to produce around 50% of the names of contemporary celebrities, but performed significantly better on a task calling for naming of historical figures. The names of relatives and friends were spared in one patient, while the other retrieved names of people known since childhood much better than those of people familiar to him since the age of 25. Geographical names, names of monuments and masterpieces were preserved. The above dissociations are taken to imply that in moderately impaired patients, a temporal gradient effect concurs to modulate the severity of the naming block. A similar impairment was found in both patients when they attempted to retrieve or relearn familiar telephone numbers. This finding suggests that the core of the disorder resides in the inability to gain access to words used to identify a single entity, regardless of whether they belong to the class of proper or common names.

Effects of parietal lesions in humans on color and location priming.

To determine whether the parietal lobes contribute tot he selection of nonspatial features known to be processed in the ventral stream, the current study examined the effect of chronic unilateral parietal lobe lesions in humans on color and location priming. Patients and normal controls performed a go/no-go color discrimination task in which either the same color and different color pairs of stimuli (prime and probe) were projected sequentially either in the same hemifield or in opposite hemifields. Control subjects and patients both showed independent effects of color and location priming. In the patients, primes in either field produced color priming for target probes in the ipsilesional field but not for probes in the contralesional field. This observation implicates the parietal cortex in processing activated codes of stimulus attributes not only for spatial information but also for visual features processed in the ventral visual pathways.

Reading of lexically stressed words by Italian aphasic patients: a retrospective study.

This retrospective study investigated whether there is evidence of a 3rd reading mechanism in a transparent orthography such as Italian, where (nearly) all words can be read through the sublexical route but stress cannot always be assigned by orthography-to-phonology rules. The presence and frequency of stress errors in lexically stressed words in 16 aphasic patients with impaired reading comprehension of those same words was checked. Nine patients were reexamined months later. Notwithstanding impaired reading comprehension, none of the patients made stress errors at first examination. At follow-up, all patients showed improvement of reading comprehension and only 2 patients still had better preserved oral reading. The authors concluded that even in transparent orthographies such as Italian, the noninteractive dual-route model is inadequate for explaining all patterns of reading performances. In nonprogressive aphasias, reading comprehension can recover in a larger number of patients, reducing the amplitude of the dissociation between reading aloud and reading comprehension and reducing the number of patients showing this dissociation.

Let not thy left hand know what thy right hand knoweth. The case of a patient with an infarct involving the callosal pathways.

Following a cerebral vascular accident, a patient showed a classical disconnection syndrome: left-hand tactile anomia, apraxia and dysgraphia and right-hand constructional apraxia. What made the case unusual was the presence of hand asymmetry in the performance of some matching-to-sample tasks carried out in foveal vision. The left hand committed significantly more errors than the right hand when it was not possible to identify on a perceptual basis the stimulus that was to be matched, because it was removed (memory condition) or was indicated verbally (verbo-visual matching), or had the same name but not the same physical appearance as the match (capital and lower-case letter matching). No hand difference emerged when the stimulus remained in full view throughout the matching task (perceptual condition). The hand effect, however, was limited to colours and letters. Objects, geometrical shapes and unfamiliar faces were matched with equal proficiency by both hands under every condition of presentation. Left-hand errors also significantly outnumbered right-hand errors in sorting colours according to hue and colouring drawings. MRI showed an infarct in the left cingulate white matter that ran parallel to the trunk of the corpus callosum, and an infarct of the splenium. However, the latter did not prevent the transmission of colour and letter information between the two hemispheres, as shown by the performance on perceptual equivalence tasks and by the correct right-hand responses to stimuli projected to the left visual field. We propose that this pattern of deficit is contingent upon the specific role that the left hemisphere plays in categorizing a given colour patch as belonging to a definite colour region (red, blue, etc.) and in grapheme recognition. Without the assistance of the left side the right hemisphere lacks the benefit provided by meaning identification. In our patient the left brain did receive information from the right brain and was able to process it, but was prevented by the paracallosal lesion from transmitting what it knew to the right motor area. No hand effect emerged for objects and geometrical shapes, because their semantic memory is bilaterally represented.

Response bias in color priming.

Four experiments investigated the role of response bias in color priming. Subjects were shown three prime-target pair conditions: same color trials, category priming trials (in which prime and target were different colors associated with the same response category) and incongruent trials. The subjects' task ('go-no-go' vs. 'two-choice' RT, Experiments 1-2), the categorization criterion of the stimuli (Experiment 3) and the proportion of the same versus different response trials (Experiment 4) were manipulated to influence the amount of response bias. Overall, the results indicate that color priming is produced whether or not a bias is generated at the response level, suggesting that the mechanisms underlying the two effects are largely independent of each other.

Evolution of oral and written confrontation naming errors in aphasia. A retrospective study on vascular patients.

Impaired naming is a common finding in aphasia but while it is known that naming errors diminish over time, longitudinal studies are rare. In this retrospective study, naming errors of 84 vascular aphasic patients are studied. Errors in oral and written confrontation naming tasks in two successive evaluations are tabulated and coded into one of 10 error types. No Response, Word-Finding Difficulty, Semantic Paraphasia, Unrelated Paraphasia, Phonemic/Orthographic Paraphasia, Neologism, Paraphasic Jargon, Phonemic/Neologistic Jargon, Stereotypy, and Other. All analyses were carried out on the difference scores, that is, the score in the second examination minus the score in the first examination. Results indicate that there is a significant decrease of No Responses (in oral and written naming) and Neologisms (in oral naming), and a significant increase of Orthographic Paraphasias in written naming. Moreover, the difference score for Phonemic/Orthographic Paraphasias was higher in written than oral naming. The difference scores for the other types of error were not statistically significant.

Residual orthographic and phonological knowledge in an anomic patient.

A 54-year-old man with left-hemisphere damage and severe aphasia: initially showed dissociation between oral and written naming, with written naming faring better. He also had an unusual processing of homophones and demonstrated "spatial" encoding of residual orthographic knowledge. The analysis affords an opportunity to investigate the mechanisms underlying the processing of single words.

Priming effect in a color discrimination task.

Two experiments were run to test whether the automatic coding of colors generates priming effects. Subjects were tachistoscopically presented a series of prime-target sequences. The prime stimulus could be either a red, green, or black circular dot, followed by a red or green annular ring (target). The role of automatic and conscious mechanisms was investigated in Exp. 1 by manipulating the predictive validity of the prime stimuli (80%, 50%, 20%), keeping constant the value of stimulus-onset asynchrony (350 msec.). Analysis showed priming effects even in the low predictive condition, where no conscious expectations could be activated. In Exp. 2, three different values of stimulus-onset asynchrony were used, 150, 350, and 2100 msec. Priming effects were obtained in the short and medium stimulus-onset asynchrony condition but not in the long one. Over-all, the data of both experiments produce converging evidence which indicates that the automatic elaboration of colored stimuli may produce priming effects.