Current exposure to a second language modulates bilingual visual word recognition: An EEG study.

Bilingual word recognition has been the focus of much empirical work, but research on potential modulating factors, such as individual differences in L2 exposure, are limited. This study represents a first attempt to determine the impact of L2-exposure on bilingual word recognition in both languages. To this end, highly fluent bilinguals were split into two groups according to their L2-exposure, and performed a semantic categorisation task while recording their behavioural responses and electro-cortical (EEG) signal. We predicted that lower L2-exposure should produce less efficient L2 word recognition processing at the behavioural level, alongside neurophysiological changes at the early pre-lexical and lexical levels, but not at a post-lexical level. Results confirmed this hypothesis in accuracy and in the N1 component of the EEG signal. Precisely, bilinguals with lower L2-exposure appeared less accurate in determining semantic relatedness when target words were presented in L2, but this condition posed no such problem for bilinguals with higher L2-exposure. Moreover, L2-exposure modulates early processes of word recognition not only in L2 but also in L1 brain activity, thus challenging a fully non-selective access account (cf. BIA + model, Dijkstra and van Heuven, 2002). We interpret our findings with reference to the frequency-lag hypothesis (Gollan et al., 2011).

Biofeedback can reduce foot pressure to a safe level and without causing new at-risk zones in patients with diabetes and peripheral neuropathy.

BACKGROUND: Plantar pressure reduction is mandatory for diabetic foot ulcer healing. Our aim was to evaluate the impact of a new walking strategy learned by biofeedback on plantar pressure distribution under both feet in patients with diabetic peripheral neuropathy. METHODS: Terminally augmented biofeedback has been used for foot off-loading training in 21 patients with diabetic peripheral sensory neuropathy. The biofeedback technique was based on a subjective estimation of performance and objective visual feedback following walking sequences. The patient was considered to have learned a new walking strategy as soon as the peak plantar pressure (PPP) under the previously defined at-risk zone was within a range of 40-80% of baseline PPP in 70% of the totality of steps and during three consecutive walking sequences. The PPP was measured by a portable in-shoe foot pressure measurement system (PEDAR(®)) at baseline (T0), directly after learning (T1) and at 10-day retention test (T2). RESULTS: The PPP under at-risk zones decreased significantly at T1 (165 ± 9 kPa, p < 0.0001) and T2 (167 ± 11, p = 0.001), as compared with T0 (242 ± 12 kPa) without any increase of the PPP elsewhere. At the contralateral foot (not concerned by off-loading), the PPP was slightly higher under the lateral midfoot at T1 (68 ± 8 kPa, p = 0.01) and T2 (65 ± 8 kPa, p = 0.01), as compared with T0 (58 ± 6 kPa). CONCLUSIONS: The foot off-loading by biofeedback leads to a safe and regular plantar pressure distribution without inducing any new 'at-risk' area under both feet.

Biofeedback for foot offloading in diabetic patients with peripheral neuropathy.

AIMS: The reduction of high plantar pressure in diabetic patients with peripheral neuropathy is mandatory for prevention of foot ulcers and amputations. We used a new biofeedback-based method to reduce the plantar pressure at an at-risk area of foot in diabetic patients with peripheral neuropathy. METHODS: Thirteen diabetic patients (age 60.8 +/- 12.3 years, body mass index 29.0 +/- 5.0 kg/m(2)) with peripheral neuropathy of the lower limbs were studied. Patients with memory impairment were excluded. The portable in-shoe foot pressure measurement system (PEDAR) was used for foot offloading training by biofeedback. The learning procedure consisted in sequences of walking (10 steps), each followed by a subjective estimation of performance and objective feedback. The goal was to achieve three consecutive walking cycles of 10 steps, with a minimum of seven steps inside the range of 40-80% of the baseline peak plantar pressure. The peak plantar pressure was assessed during the learning period and at retention tests. RESULTS: A significant difference in peak plantar pressure was recorded between the beginning and the end of the learning period (when the target for plantar pressure was achieved) (262 +/- 70 vs. 191 +/- 53 kPa; P = 0.002). The statistically significant difference between the beginning of learning and all retention tests persisted, even at the 10-day follow-up. CONCLUSIONS: Terminal augmented feedback training may positively affect motor learning in diabetic patients with peripheral neuropathy and could possibly lead to suitable foot offloading. Additional research is needed to confirm the maintenance of offloading in the long term.