Katy Borodkin

Circadian rhythm sleep disorders following mild traumatic brain injury

Objective: To describe the physiologic and behavioral characteristics of circadian rhythm sleep disorders (CRSDs) following minor traumatic brain injury (mTBI) in patients complaining of insomnia. Methods: Forty two patients with insomnia complaints following mTBI were screened. Those suspected of having CRSD underwent actigraphy, saliva melatonin and oral temperature measurement, and polysomnography. All patients also filled out a self-reported questionnaire to determine their circadian preference. Results: Fifteen of the 42 patients (36%) with complaints of insomnia following mTBI were diagnosed with CRSD. Eight patients displayed a delayed sleep phase syndrome (DSPS), whereas seven displayed an irregular sleep–wake pattern (ISWP). Whereas all patients with DSPS exhibited a 24-hour periodicity of oral temperature rhythm, three of seven patients with ISWP lacked such a daily rhythm. In addition, ISWP patients exhibited smaller amplitude of oral temperature rhythm vs the DSPS group. Subjective Morningness–Eveningness Questionnaire scores were in accordance with the clinical diagnosis of DSPS or ISWP based on actigraphy. Conclusions: Minor traumatic brain injury might contribute to the emergence of circadian rhythm sleep disorders. Two types of these disorders were observed: delayed sleep phase syndrome and irregular sleep–wake pattern. The types differed in the subjective questionnaire scores and had distinct profiles of melatonin and temperature circadian rhythms.

Melatonin Treatment in Adolescents With Delayed Sleep Phase Syndrome

This retrospective study describes the effects of long-term treatment with melatonin in 33 adolescents (age range, 10-18 years) with delayed sleep phase syndrome (DSPS). Patients were treated with oral melatonin, 3 to 5 mg/day for an average period of 6 months. During the treatment, sleep onset was advanced and sleep duration was longer. Treatment was also associated with a decrease in the proportion of patients reporting school difficulties. No adverse effects of melatonin were noted. This study indicates that long-term treatment with melatonin can be beneficial for adolescents with DSPS in terms of sleep-wake schedule and school performance.

DYSREGULATION OF CIRCADIAN RHYTHMS FOLLOWING PROLACTIN-SECRETING PITUITARY MICROADENOMA

A patient who developed an irregular sleep‐wake pattern following prolactin‐secreting pituitary microadenoma is described. The patient reported difficulties in sleep onset and awakening at the desired time, which caused major dysfunction in his daily life activities. Despite these difficulties, the sleep‐related complaints of the patient remained unrecognized for as long as three yrs. Statistical analyses of the patients rest‐activity patterns revealed that the disruption of the sleep‐wake circadian rhythm originated from a disharmony between ultradian (semicircadian) and circadian components. The circadian component displayed shorter than 24 h periodicity most of the time, but the semicircadian component fluctuated between longer and shorter than 12 h periods. Additionally, desynchrony in terms of period length was found in the tentative analyses of the rest‐activity pattern, salivary melatonin, and oral temperature. While the salivary melatonin time series data could be characterized by a best‐fit cosine curve of 24 h, the time series data of oral temperature was more compatible with 28 h best‐fit curve. The rest‐activity cycle during the simultaneous measurements, however, was best approximated by a best‐fit curve of 21h. The dysregulation of circadian rhythms occurred concomitantly, but not beforehand, with the onset of pituitary disease, thus suggesting an association between the two phenomena. This association may have interesting implications to the modeling of the circadian time‐keeping system. This case also highlights the need to raise the awareness to circadian rhythm sleep disorders and to consider disruptions of sleep-wake cycle in patients with pituitary adenoma.

When pumpkin is closer to onion than to squash: The structure of the second language lexicon

The current research investigated the organization of the second language mental lexicon. Twenty-seven English-Hebrew bilingual speakers (who spoke Hebrew as their second language) completed a semantic fluency task in each of their languages, and 24 native Hebrew speakers completed the task in Hebrew. Responses were compared within and across groups, using computational tools. The analyses indicated that the lexical network of the second language displayed greater local connectivity and less modular community structure than the network in the native language, both in the entire sample and in a sub-sample of bilinguals whose Hebrew vocabulary was matched to that of the native Hebrew speakers. These findings suggest that the lexical network of the second language is not as well-organized as is the network of the first language, even in highly proficient bilinguals. The structural characteristics of the second language lexicon might be affected by factors related to language learning history, including age of acquisition and language use.

Hemispheric involvement in native and non-native comprehension of conventional metaphors

Abstract The present study examined hemispheric processing of conventional metaphors in native (L1) and non-native (L2) language using the divided visual field technique. Participants included 25 native Hebrew speakers and 24 bilinguals who acquired English as L1 and Hebrew as L2. In Experiment 1, the two groups performed a semantic judgment task on conventional metaphors and literal Hebrew word pairs, and in Experiment 2, the processing of the expressions was compared between the two L1s. The results of the two experiments demonstrated a left hemisphere advantage for processing conventional metaphoric expressions in L1, but a right hemisphere advantage for processing the same kind of stimuli in L2. No such L1-L2 difference in hemispheric involvement was observed for literal word pairs. These results support the Fine-Coarse Semantic Coding Theory and the Graded Salience Hypothesis and suggest that the metaphoric meanings of conventional metaphors may appear less salient for a non-native speaker.

Naming Abilities in Low-Proficiency Second Language Learners

Difficulties in second language (L2) learning are often associated with recognizable learning difficulties in native language (L1), such as in dyslexia. However, some individuals have low L2 proficiency but intact L1 reading skills. These L2 learners experience frequent tip-of-the-tongue states while naming in L1, which indicates that they have a weakness in retrieval of phonological codes of words. The authors hypothesized that if naming ability is shared across languages, this difficulty would reemerge in L2 naming, which was tested using the tip-of-the-tongue experimental paradigm. Consistent with this hypothesis, low-proficiency L2 learners (n = 15) reported more tip-of-the-tongue states, more frequently mispronounced correctly retrieved words, and benefited less from phonological cuing compared to high-proficiency L2 learners (n = 23). It is notable that low-proficiency L2 learners performed worse than individuals with dyslexia (n = 16) on some of these measures, despite the same level of L2 proficiency. These results indicate that L2 naming difficulties of low-proficiency L2 learners are a manifestation not merely of their low L2 proficiency but rather of a general weakness in phonological word form retrieval, which is shared across languages. More broadly, the study provides further evidence for the existence of a distinct profile of cognitive weaknesses characteristic of the behavioral phenotype of low-proficiency L2 learners.

Tip-of-the-tongue (TOT) states and cross-linguistic transfer

This study examined cross-linguistic transfer in oral language skills in a sample of 50 native Hebrew speakers who learned English as a second language. The ability to retrieve phonological forms of words in naming, as manifested by the tendency to experience tip-of-the-tongue states, was correlated across languages. We also found within and across language correlations between this ability and grammatical accuracy, lexical diversity, and syntactic complexity in second language narratives. These findings are consistent with the transfer across languages in oral language skills and provide insights into the processes linking phonological and higher level encoding in production of connected speech.

The role of language proficiency and linguistic distance in cross-linguistic treatment effects in aphasia

ABSTRACT Current findings from intervention in bilingual aphasia are inconclusive regarding the extent to which levels of language proficiency and degree of linguistic distance between treated and non-treated languages influence cross-language generalisation and changes in levels of language activation and inhibition following treatment. In this study, we enrolled a 65-year-old multilingual speaker with aphasia and administered treatment in his L1, Dutch. We assessed pre- and post-treatment performance for seven of his languages, five of high proficiency and two of lower proficiency. We asked whether treatment in L1 would generalise to his other languages or increase interference among them. Forty hours of treatment were completed over the course of five weeks. Each language was tested three times at pretreatment and at post-treatment. Testing included measures of narrative production, answering questions, picture description and question generation. Dependent measures examined language efficiency, defined as Correct Information Units (CIUs)/min, as well as language mixing, defined as proportion of code-mixed whole words. We found that our participant’s improved efficiency in Dutch was mirrored by parallel improvement in the four languages of high proficiency: English, German, Italian and French. In contrast, in his languages of lower proficiency, Norwegian and Spanish, improved efficiency was limited. An increase in code-mixing was noted in Spanish, but not in Norwegian. We interpret the increased code-mixing in Spanish as indication of heightened inhibition following improvement in a language of close linguistic proximity, Italian. We conclude that an interaction of language proficiency and linguistic similarity affects cross-language generalisation following intervention in multilingual aphasia.

The ineffectiveness of magnotherapy in a patient with obstructive sleep apnea syndrome and cardiovascular comorbidity.

Obstructive sleep apnea syndrome (OSAS) is associated with mild to severe cardiovascular risks. The most common standard treatment for OSAS, continuous positive airway pressure, was found to have beneficial effects on cardiovascular sequelae of OSAS. Additionally, commercial companies promote nonprescription treatments for OSAS. These products frequently lack scientific support for their efficacy and need further research. We report an objective test of magnetic therapy, one such product, in a patient with OSAS and cardiovascular comorbidities. Two nights of polysomnographic recording using the split-night protocol did not reveal any consistent differences in OSAS symptoms whether the patient slept with or without the magnetic equipment. It was concluded that magnetic treatment was unsuccessful in reducing OSAS symptoms in our patient and may even increase possible cardiovascular and stroke risks by preventing the patient from pursuing an adequate medical treatment, such as continuous positive airway pressure.

Developmental changes in hemispheric processing of ambiguous words during adolescence

Abstract Previous research has provided evidence of a hemispheric asymmetry in processing dominant and subordinate associations of ambiguous words. However, developmental changes of this hemispheric asymmetry have been little studied. We used the divided visual field paradigm to examine the pattern of hemispheric involvement in ambiguity resolution in 31 Hebrew-speaking adolescents and 41 young adults. Participants performed a semantic judgement task on word pairs, where the first word was an ambiguous word (presented centrally) and the second word was related to either its dominant or subordinate meaning (presented laterally after a 750 ms stimulus onset asynchrony). In both groups, no difference was found between the visual fields performance in the dominant meaning condition. However, in the subordinate meaning condition, adolescents (but not adults) responded slower in the left visual field/right hemisphere. These results suggest that the role of RH in the broader semantic search of distant meanings become refined over adolescence, which might be related to the significant development of figurative language during this period. This study may extend the scope of the Fine-Coarse Semantic Coding Theory by including a developmental perspective.