Acoustic cry characteristics of infants exposed to methadone during pregnancy

Acoustic Cry Characteristics of Infants as a Marker of Neurological Dysfunction: A Systematic Review and Meta-Analysis

BACKGROUND

Atypical cries have been identified in infants with neurological dysfunction. The aim of this study was to conduct a systematic review and meta-analysis to appraise existing evidence for associations between acoustic cry characteristics and neurological dysfunction in infants aged 18 months or less.

METHODS

PubMed/MEDLINE, PsycINFO, CINAHL, and Embase were searched for original, peer-reviewed studies published in English reporting cry variables in infants aged 18 months or less with or at risk of neurological dysfunction. Studies without a nonneurologically impaired control sample were excluded. Pooled effect sizes were estimated using standardized mean difference (SMD) and odds ratio (OR). I² indicated study heterogeneity, and the risk of bias was assessed using the Newcastle-Ottawa Scale.

RESULTS

From March 2018 to February 2019, 28,294 studies were retrieved. Eight were meta-analyzed. Infants with or at risk of neurological dysfunction exhibited higher mean (SMD = 0.11 [95% confidence interval, 0.00 to 0.23]) and minimum (SMD = 0.93 [0.64 to 1.23]) fundamental frequency; higher odds of hyperphonation (OR = 13.17 [1.05 to 165.87]), biphonation (OR = 10.62 [1.53 to 73.59]), rise-fall-rise melodies (OR = 4.66 [1.16 to 18.66]), and flat melodies (OR = 4.47 [1.27 to 15.68]); and lower odds of fall-rise-fall melodies (OR = 0.21 [0.05 to 0.83]).

CONCLUSIONS

Infants with underlying neuropathology have unique cries characterized by higher fundamental frequency, dysphonation, and atypical melodies, although study heterogeneity and imprecision of effect size estimates limited our interpretation. Assessment of acoustic cry characteristics offers the potential for noninvasive, rapid, point-of-care screening for neurologically high-risk infants.

Research gaps on methadone harms and comparative harms: findings from a review of the evidence for an American Pain Society and College on Problems of Drug Dependence clinical practice guideline

Methadone-associated overdose deaths have dramatically increased. In order to inform an evidence-based clinical practice guideline to improve safety of methadone prescribing, the American Pain Society commissioned a systematic review on various aspects related to methadone safety. We searched Ovid MEDLINE, Cochrane Library, and PsycINFO databases through July 2012 to identify studies that addressed 1 or more of 17 Key Questions related to methadone safety; an update search was performed in 2014 for new studies related to methadone-related overdose and risks related to cardiac arrhythmias. A total of 168 studies met inclusion criteria for the review. The purpose of this article is to highlight critical research gaps in the literature related to methadone safety. These include lack of evidence on risk factors associated with methadone-overdose deaths and adverse events, limited evidence to evaluate the comparative mortality of methadone versus other opioids, insufficient evidence to fully understand the harms associated with methadone use during pregnancy, and insufficient evidence to determine effects of risk mitigation strategies such as electrocardiogram monitoring, strategies for managing patients with prolonged QTc intervals on screening, urine drug testing, alternative dosing regimens for initiation and titration of therapy, and timing of follow-up. Therefore, most guideline recommendations are based on weak evidence. More research is needed to guide safe methadone prescribing practices and decrease the adverse events associated with methadone.

PERSPECTIVE

This article summarizes critical research gaps in the literature related to methadone safety, based on a systematic review commissioned by the American Pain Society. Critical research gaps were identified in a number of areas, highlighting the need for additional research to guide safer prescribing and risk mitigation strategies.

Methadone safety: a clinical practice guideline from the American Pain Society and College on Problems of Drug Dependence, in collaboration with the Heart Rhythm Society

Methadone is used for the treatment of opioid addiction and for treatment of chronic pain. The safety of methadone has been called into question by data indicating a large increase in the number of methadone-associated overdose deaths in recent years that has occurred in parallel with a dramatic rise in the use of methadone for chronic pain. The American Pain Society and the College on Problems of Drug Dependence, in collaboration with the Heart Rhythm Society, commissioned an interdisciplinary expert panel to develop a clinical practice guideline on safer prescribing of methadone for treatment of opioid addiction and chronic pain. As part of the guideline development process, the American Pain Society commissioned a systematic review of various aspects related to safety of methadone. After a review of the available evidence, the expert panel concluded that measures can be taken to promote safer use of methadone. Specific recommendations include the need to educate and counsel patients on methadone safety, use of electrocardiography to identify persons at greater risk for methadone-associated arrhythmia, use of alternative opioids in patients at high risk of complications related to corrected electrocardiographic QTc interval prolongation, careful dose initiation and titration of methadone, and diligent monitoring and follow-up. Although these guidelines are based on a systematic review, the panel identified numerous research gaps, most recommendations were based on low-quality evidence, and no recommendations were based on high-quality evidence.

PERSPECTIVE

This guideline, based on a systematic review of the evidence on methadone safety, provides recommendations developed by a multidisciplinary expert panel. Safe use of methadone requires clinical skills and knowledge in use of methadone to mitigate potential risks, including serious risks related to risk of overdose and cardiac arrhythmias.

Assessing neonates for neonatal abstinence: are you reliable?

Nationally, there has been a steady increase in the number of infants born with neonatal abstinence syndrome or drug withdrawal. Many of these infants remain in the hospital because their signs of withdrawal require pharmacologic management. The length of hospital stay can range from 1 week to several months depending on the severity of withdrawal. One way to decrease the length of stay and reduce the cost of care is to discharge the infant from the hospital sooner. To discharge infants sooner, their neonatal abstinence syndrome must be accurately assessed so that appropriate pharmacologic management can be administered. One way to increase the accuracy of assessing withdrawal signs is to implement an interobserver reliability protocol. This approach will allow healthcare professionals to gain consistency and accuracy in assessing infants for signs of withdrawal that may facilitate earlier discharge from the hospital.

The covariation of acoustic features of infant cries and autonomic state

The evolution of the autonomic nervous system provides an organizing principle to interpret the adaptive significance of physiological systems in promoting social behavior and responding to social challenges. This phylogenetic shift in neural regulation of the autonomic nervous system in mammals has produced a neuroanatomically integrated social engagement system, including neural mechanisms that regulate both cardiac vagal tone and muscles involved in vocalization. Mammalian vocalizations are part of a conspecific social communication system, with several mammalian species modulating acoustic features of vocalizations to signal affective state. Prosody, defined by variations in rhythm and pitch, is a feature of mammalian vocalizations that communicate emotion and affective state. While the covariation between physiological state and the acoustic frequencies of vocalizations is neurophysiologically based, few studies have investigated the covariation between vocal prosody and autonomic state. In response to this paucity of scientific evidence, the current study explored the utility of vocal prosody as a sensitive index of autonomic activity in human infants during the Still Face challenge. Overall, significant correlations were observed between several acoustic features of the infant vocalizations and autonomic state, demonstrating an association between shorter heart period and reductions in heart period and respiratory sinus arrhythmia following the challenge with the dampening of the modulation of acoustic features (fundamental frequency, variance, 50% bandwidth, and duration) that are perceived as prosody.

Atypical cry acoustics in 6-month-old infants at risk for autism spectrum disorder

This study examined differences in acoustic characteristics of infant cries in a sample of babies at risk for autism and a low-risk comparison group. Cry samples derived from vocal recordings of 6-month-old infants at risk for autism spectrum disorder (ASD; n = 21) and low-risk infants (n = 18) were subjected to acoustic analyses using analysis software designed for this purpose. Cries were categorized as either pain-related or non-pain-related based on videotape coding. At-risk infants produced pain-related cries with higher and more variable fundamental frequency (F (0) ) than low-risk infants. At-risk infants later classified with ASD at 36 months had among the highest F (0) values for both types of cries and produced cries that were more poorly phonated than those of nonautistic infants, reflecting cries that were less likely to be produced in a voiced mode. These results provide preliminary evidence that disruptions in cry acoustics may be part of an atypical vocal signature of autism in early life.

Neural tract development of infants born to methadone-maintained mothers

The early cerebral connective tract development of infants born to methadone-maintained mothers and comparison infants was examined using diffusion tensor imaging. Drawing on animal models, we hypothesized higher mean diffusivity in methadone-exposed infants, corresponding to the delayed or altered maturation of neural connective tracts. Thirteen methadone-exposed infants and seven comparison infants were scanned within 13-44 days after birth. Mean diffusivity was compared across groups voxelwise throughout a common white matter skeleton defined for the sample, and in probabilistically defined tracts of interest overlapping the skeleton, i.e., the superior and inferior longitudinal fasciculi. Higher mean diffusivity (P < 0.05) in methadone-exposed infants was evident in the superior longitudinal fasciculus regionally by voxelwise analysis and whole-tract analysis. These results are preliminary, given the small sample. However, all observed effects were in the hypothesized direction, with methadone-exposed infants exhibiting higher mean diffusivity, suggesting altered maturation of connective tracts. Such differences may underlie some of the increased risk for cognitive and behavioral difficulties in children born to mothers using opioids. These findings highlight the need for further assessments of the effects of prenatal methadone exposure on neural development.

Subsequent anxiety-related behavior in rats exposed to low-dose methadone during gestation, lactation or both periods consecutively

In order to assess the long-term behavioral consequences of exposing rats to methadone during gestation, lactation or both periods consecutively, pregnant Wistar dams were provided with drinking water containing approximately 2.39 mg/kg/day methadone. Soon after birth, litters of offspring were assigned to methadone-naïve foster mothers. Half of these foster mothers were then provided with drinking water containing methadone (approximately 2.86 mg/kg/day), while the other half received unadulterated water. Maternal weight gain, pregnancy duration, litter sizes, sex ratios and average pup weights were recorded. Following weaning on postnatal day (PND) 28, individual rats were weighed and inspected for physical abnormalities and stress reactions at PND20, 60 and 120. At these same ages, observations were also made of the rats' behavior in an emergence apparatus, and an open field. Apart from a smaller number of full-term pregnancies, there were no effects of any type of methadone treatment on physical measurements recorded at any age. Nor were there any behavioral effects of gestational methadone experienced on its own. However, methadone experienced during lactation (without gestational exposure) decreased emergence speed at PND30, and for all testing ages combined, increased open-field ambulation (males only), walking, rearing and occupancy of the center of the apparatus. Exposure to methadone during both gestation and lactation decreased emergence latencies at PND30 and, for all ages combined, decreased ambulation (males only), center occupancy and defecation. The subsequent behavioral effects of methadone were largely confined to lactational exposure and, when combined with gestational exposure, suggested increased anxiety.

Maternal methadone dose during pregnancy and infant clinical outcome

In recent decades there has been an increase in the methadone dosages prescribed for opioid dependent women during pregnancy. Using prospective longitudinal data from a cohort of 32 methadone exposed and 42 non-methadone exposed infants, this study examined the relationship between maternal methadone dose during pregnancy and a range of infant clinical outcomes. Of particular interest was the extent to which any observed associations might reflect the direct causal effects of maternal methadone dose and/or the confounding effects of adverse maternal lifestyle factors correlated with methadone use during pregnancy. Findings revealed the presence of clear linear relationships between the mean methadone dose prescribed for mothers during pregnancy and a range of adverse infant clinical outcomes. With increasing maternal methadone dose there was a corresponding increase in infants' risk of being born preterm, being symmetrically smaller, spending longer periods in hospital and the need for treatment for Neonatal Abstinence Syndrome. After due allowance for potentially confounding maternal health and lifestyle factors, maternal methadone dose during pregnancy remained a significant predictor of preterm birth, growth, and the duration of infant hospitalization post delivery. These findings suggest a need to examine more closely the potential impacts of recent trends towards the use of higher methadone dose levels during pregnancy.