Shape Discrimination Using the Tongue: Implications for a Visual-to-Tactile Sensory Substitution Device

Sensory substitution devices have the potential to provide individuals with visual impairments with more information about their environments, which may help them recognize objects and achieve more independence in their daily lives. However, many of these devices may require extensive training and might be limited in the amount of information that they can convey. We tested the effectiveness and assessed some of the limitations of the BrainPort device, which provides stimulation through a 20 × 20 electrode grid array on the tongue. Across five experiments, including one with blind individuals, we found that subjects were unable to accurately discriminate between simple shapes as well as different line orientations that were briefly presented on the tongue, even after 300 trials of practice with the device. These experiments indicate that such a minimal training regimen with the BrainPort is not sufficient for object recognition, raising serious concerns about the usability of this device without extensive training

Ketamine augmentation for major depressive disorder and suicidal ideation: preliminary experience in an inpatient psychiatry setting

Background Ketamine is known to rapidly reduce depressive symptoms and suicidal ideation (SI) in patients with major depressive disorder (MDD), but evidence is limited for its acceptability and effectiveness in “real-world” settings. This case series examines serial ketamine infusions in reducing SI and depression scores in adults with MDD admitted to a tertiary care hospital. Methods Five inpatients with MDD and SI admitted to hospital in Toronto, Canada received six infusions of 0.5 mg/kg intravenous (IV) ketamine (n = 5) over approximately 12 days, in addition to treatment-as-usual. Suicide and depression rating scores (Scale for Suicidal Ideation, SSI; Montgomery-Åsberg Depression Rating Scale, MADRS) were obtained at baseline, on treatment days, on days 14 and 42 (primary endpoint). Results All patients experienced benefit with ketamine. SSI scores diminished by 84% from 14.0 ± 4.5 at baseline to 2.2 ± 2.5 at study endpoint. MADRS scores diminished by 47% from 42.2 ± 5.3 at baseline to 22.4 ± 8.0. Two patients withdrew from the study, one to initiate electroconvulsive therapy and one due to an adverse event (dissociative effects) during the ketamine infusion. Limitations The major limitation of this study is the small sample size. Discussion These preliminary pilot data are promising with a greater than two-fold reduction in SI following ketamine infusions. They demonstrate that six serial ketamine infusions may be safe and feasible. These findings support the need for large scale randomized controlled trials to confirm the efficacy of serial ketamine for treatment of SI in “real-world” setting