Comparison of nimodipine formulations and administration techniques via enteral feeding tubes in patients with aneurysmal subarachnoid hemorrhage: A multicenter retrospective cohort study.

BACKGROUND: Nimodipine improves outcomes following aneurysmal subarachnoid hemorrhage (aSAH) and current guidelines suggest that patients with aSAH receive nimodipine for 21 days. Patients with no difficulty swallowing will swallow the whole capsules or tablets; otherwise, nimodipine liquid must be drawn from capsules, tablets need to be crushed, or the commercially available liquid product be used to facilitate administration through an enteral feeding tube (FT). It is not clear whether these techniques are equivalent. The goal of the study was to determine if different nimodipine formulations and administration techniques were associated with the safety and effectiveness of nimodipine in aSAH. METHODS: This was a retrospective multicenter observational cohort study conducted in 21 hospitals across North America. Patients admitted with aSAH and received nimodipine by FT for ≥3 days were included. Patient demographics, disease severity, nimodipine administration, and study outcomes were collected. Safety end points included the prevalence of diarrhea and nimodipine dose reduction or discontinuation secondary to blood pressure reduction. Predictors of the study outcomes were analyzed using regression modeling. RESULTS: A total of 727 patients were included. Administration of nimodipine liquid product was independently associated with higher prevalence of diarrhea compared to other administration techniques/formulations (Odds ratio [OR] 2.28, 95% confidence interval [CI] 1.41-3.67, p-value = 0.001, OR 2.76, 95% CI 1.37-5.55, p-value = 0.005, for old and new commercially available formulations, respectively). Bedside withdrawal of liquid from nimodipine capsules prior to administration was significantly associated with higher prevalence of nimodipine dose reduction or discontinuation secondary to hypotension (OR 2.82, 95% CI 1.57-5.06, p-value = 0.001). Tablet crushing and bedside withdrawal of liquid from capsules prior to administration were associated with increased odds of delayed cerebral ischemia (OR 6.66, 95% CI 3.48-12.74, p-value <0.0001 and OR 3.92, 95% CI 2.05-7.52, p-value <0.0001, respectively). CONCLUSIONS: Our findings suggest that enteral nimodipine formulations and administration techniques might not be equivalent. This could be attributed to excipient differences, inconsistency and inaccuracy in medication administration, and altered nimodipine bioavailability. Further studies are needed.

"Where are the . . . Fixations?": Grammatical number cues guide anticipatory fixations to upcoming referents and reduce lexical competition.

Listeners make use of contextual cues during continuous speech processing that help overcome the limitations of the acoustic input. These semantic, grammatical, and pragmatic cues facilitate prediction of upcoming words and/or reduce the lexical search space by inhibiting activation of contextually inappropriate words that share phonological information with the target. The current study used the visual world paradigm to assess whether and how listeners use contextual cues about grammatical number during sentence processing by presenting target words in carrier phrases that were grammatically unconstraining ("Click on the . . .") or grammatically constraining ("Where is/are the . . ."). Prior to the onset of the target word, listeners were already more likely to fixate on plural objects in the "Where are the . . ." context than the "Where is the . . ." context, indicating that they used the construction of the verb to anticipate the referent. Further, participants showed less interference from cohort competitors when the sentence frame made them contextually inappropriate, but still fixated on those words more than on phonologically unrelated distractor words. These results suggest that listeners rapidly and flexibly make use of contextual cues about grammatical number while maintaining sensitivity to the bottom-up input. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Transformation of a temporal speech cue to a spatial neural code in human auditory cortex.

In speech, listeners extract continuously-varying spectrotemporal cues from the acoustic signal to perceive discrete phonetic categories. Spectral cues are spatially encoded in the amplitude of responses in phonetically-tuned neural populations in auditory cortex. It remains unknown whether similar neurophysiological mechanisms encode temporal cues like voice-onset time (VOT), which distinguishes sounds like /b/ and/p/. We used direct brain recordings in humans to investigate the neural encoding of temporal speech cues with a VOT continuum from /ba/ to /pa/. We found that distinct neural populations respond preferentially to VOTs from one phonetic category, and are also sensitive to sub-phonetic VOT differences within a population's preferred category. In a simple neural network model, simulated populations tuned to detect either temporal gaps or coincidences between spectral cues captured encoding patterns observed in real neural data. These results demonstrate that a spatial/amplitude neural code underlies the cortical representation of both spectral and temporal speech cues.

Development and validation of the self-care counseling rubric (SCCR) to assess student self-care counseling skills.

INTRODUCTION: To describe the development and validation of the self-care counseling rubric (SCCR) to assess student self-care counseling skills. METHODS: Over two years of implementation, a comprehensive rubric was developed and revised for faculty to use. Students were assessed using the rubric in weekly, simulated patient encounters on self-care topics already taught in didactic material. The rubric underwent analysis for validation. Simulated encounters were recorded to assess inter-rater reliability. RESULTS: The internal consistency (Cronbach's alpha) of the original SCCR and revised SCCR were 0.81 and 0.85, respectively. The mean intraclass correlation of the original SCCR and revised SCCR was 0.27 and 0.66, respectively. CONCLUSIONS: The developed instrument demonstrated good reliability in assessing student self-care counseling performance. The revised SCCR can be an efficient and effective approach to track student competence in self-care counseling.

Speaker-normalized sound representations in the human auditory cortex.

The acoustic dimensions that distinguish speech sounds (like the vowel differences in "boot" and "boat") also differentiate speakers' voices. Therefore, listeners must normalize across speakers without losing linguistic information. Past behavioral work suggests an important role for auditory contrast enhancement in normalization: preceding context affects listeners' perception of subsequent speech sounds. Here, using intracranial electrocorticography in humans, we investigate whether and how such context effects arise in auditory cortex. Participants identified speech sounds that were preceded by phrases from two different speakers whose voices differed along the same acoustic dimension as target words (the lowest resonance of the vocal tract). In every participant, target vowels evoke a speaker-dependent neural response that is consistent with the listener's perception, and which follows from a contrast enhancement model. Auditory cortex processing thus displays a critical feature of normalization, allowing listeners to extract meaningful content from the voices of diverse speakers.

Speaker information affects false recognition of unstudied lexical-semantic associates.

Recognition of and memory for a spoken word can be facilitated by a prior presentation of that word spoken by the same talker. However, it is less clear whether this speaker congruency advantage generalizes to facilitate recognition of unheard related words. The present investigation employed a false memory paradigm to examine whether information about a speaker's identity in items heard by listeners could influence the recognition of novel items (critical intruders) phonologically or semantically related to the studied items. In Experiment 1, false recognition of semantically associated critical intruders was sensitive to speaker information, though only when subjects attended to talker identity during encoding. Results from Experiment 2 also provide some evidence that talker information affects the false recognition of critical intruders. Taken together, the present findings indicate that indexical information is able to contact the lexical-semantic network to affect the processing of unheard words.

Direct electrical stimulation of human cortex evokes high gamma activity that predicts conscious somatosensory perception.

OBJECTIVE: Direct electrical stimulation (DES) is a clinical gold standard for human brain mapping and readily evokes conscious percepts, yet the neurophysiological changes underlying these percepts are not well understood. APPROACH: To determine the neural correlates of DES, we stimulated the somatosensory cortex of ten human participants at frequency-amplitude combinations that both elicited and failed to elicit conscious percepts, meanwhile recording neural activity directly surrounding the stimulation site. We then compared the neural activity of perceived trials to that of non-perceived trials. MAIN RESULTS: We found that stimulation evokes distributed high gamma activity, which correlates with conscious perception better than stimulation parameters themselves. SIGNIFICANCE: Our findings suggest that high gamma activity is a reliable biomarker for perception evoked by both natural and electrical stimuli.

Top-down effects of syntactic sentential context on phonetic processing.

Although much evidence suggests that the identification of phonetically ambiguous target words can be biased by preceding sentential context, interactive and autonomous models of speech perception disagree as to the mechanism by which higher level information affects subjects' responses. Some have suggested that the time course of context effects is incompatible with interactive models (e.g., TRACE). Two experiments examine this issue. In Experiment 1, subjects heard noun- and verb-biasing sentence contexts (e.g., Valerie hated the . . . vs. Brett hated to . . .), followed by stimuli from 2 voice-onset time continua: bay-pay (noun-verb) versus buy-pie (verb-noun). Consistent with prior research, identification of phonetically ambiguous targets was biased by the preceding context, and the size of this bias diminished in slower compared with faster responses. In Experiment 2, tokens from the same continua were embedded among filler target words beginning with /b/ or /p/ to elicit phonemically driven identification decisions and discourage word-level strategies. Results again revealed contextually biased responding, but this bias was as strong in slow as in fast responses. Together, these results suggest that phoneme identification decisions reflect robust, lasting top-down effects of lexical feedback on prelexical representations, as predicted by interactive models of speech perception.

Phonological Neighborhood Competition Affects Spoken Word Production Irrespective of Sentential Context.

Two experiments examined the influence of phonologically similar neighbors on articulation of words' initial stop consonants in order to investigate the conditions under which lexically-conditioned phonetic variation arises. In Experiment 1, participants produced words in isolation. Results showed that the voice-onset time (VOT) of a target's initial voiceless stop was predicted by its overall neighborhood density, but not by its having a voicing minimal pair. In Experiment 2, participants read aloud the same targets after semantically predictive sentence contexts and after neutral sentence contexts. Results showed that, although VOTs were shorter in words produced after predictive contexts, the neighborhood density effect on VOT production persisted irrespective of context. These findings suggest that global competition from a word's neighborhood affects spoken word production independently of contextual modulation and support models in which activation cascades automatically and obligatorily among all of a selected target word's phonological neighbors during acoustic-phonetic encoding.