Listener Knowledge Structures Commonsense Explanation

We tailor the explanations we give depending on the person asking for them – you would explain why an event happened differently depending on which of the contributing causes the listener already knows. While significant prior work focuses on how causal structure in the world influences explanation, we focus on how explanation production is modulated by listener belief. We propose a computational model framing explanation as rational communication about causal events, using a recursive theory-of-mind and language production framework to choose amongst possible explanatory utterances that minimize the divergence between speaker and listener belief about a why an event happened. We evaluate our model using some partial observer stimuli, which manipulate the listener’s stated prior knowledge about an event, and find that our model well-predicts human judgements about which of several contributing causes is the best explanation for a speaker to provide by modeling their communicative value to the listener

Efficacy of transdermal scopolamine for sialorrhea in patients with amyotrophic lateral sclerosis

Background: Sialorrhea, the excessive flow of saliva from the mouth, causes distress in about half of patients with amyotrophic lateral sclerosis (ALS). Treatments of sialorrhea in ALS include systemic anticholinergic drugs, amitriptyline, botulinum toxin injection, and salivary gland radiotherapy, although each has limitations. Scopolamine transdermal patches have been used to prevent motion sickness since the 1980s but have also been used to treat sialorrhea in oropharyngeal disease, cerebral palsy, and Parkinson’s disease. To date, no blinded, controlled studies of sialorrhea in ALS have been reported. Methods: A crossover, double-blind comparative study was conducted by randomly assigning patients to receive scopolamine or placebo patches for 1 week. Results: A total of 10 patients (three males and seven females; mean age 71.6 years) were enrolled. The mean volume of daily oral suction was decreased with scopolamine treatment. However, there were no significant differences between scopolamine and placebo in terms of a visual analogue scale of sialorrhea severity and difficulty, and the saliva item of the ALS Functional Rating Scale-Revised (ALSFRS-R). Conclusions: Our findings suggest that scopolamine patches might decrease saliva production and relieve sialorrhea in some patients with ALS. However, these findings were not statistically significant for all patients

Four mutations of the spastin gene in Japanese families with spastic paraplegia

Hereditary spastic paraplegia (HSP) is a group of genetically heterogeneous neurodegenerative disorders characterized by slowly progressive spasticity and weakness of the lower limbs. HSP is caused by failure of development or selective degeneration of the corticospinal tracts, which contain the longest axons in humans. The most common form of HSP is caused by mutations of the spastin gene (SPAST), located on chromosome 2p21-p22, which encodes spastin, one of the ATPases associated with diverse cellular activities (AAA). In this study, we detected four causative mutations of SPAST among 14 unrelated patients with spastic paraplegia. Two missense mutations (1447A-->G, 1207C-->G) and two deletion mutations (1465delT, 1475-1476delAA) were located in the AAA cassette region. Three of these four mutations were novel. Previous reports and our results suggest that the frequency of SPAST mutations is higher among Japanese patients with autosomal dominant HSP, although SPAST mutations are also observed in patients with sporadic spastic paraplegia