Table 3.

Characteristics of studies included in the review with brain mechanisms focus.

Citation Number	Article	Target Population			Methods			Results
		Age	Sample Size	Sample Characteristics	EA Measure	Additional Variables	Evidence of Reliability
[63]	Rodrigo et al. (2020)	Child age: Neglectful, M = 2.8 years, SD =1.5 Control group M = 2.1 years, SD = 1.8 Mother age: neglectful M = 29.2 years, SD = 7.0; control M = 33.43 years, SD = 3.4	48 mother–child dyads (25 neglectful and 23 non-neglectful control mothers)	Mothers with history of neglect of a child in the last 12 months, referral recorded by Child Protective Services, and complied with the indicators of the maltreatment classification system for severe neglect	Mother–child free play; EA scales: six subscales of adult and child EA scales	Mini international neuro-psychiatric interview; T1-weighted magnetic resonance imaging with the MPRAGE (magnetization prepared rapid acquisition gradient echo): gray and white matter volumes	Inter-rater reliability: sensitivity (0.94), structuring (0.90), nonhostility (0.92), nonintrusiveness (0.87), responsiveness (0.92), and involvement (0.86)	Smaller gray matter volume in the right insula, anterior/middle cingulate, and right inferior frontal gyrus and less white matter volume in bilateral frontal regions in the neglectful mothers compared to non-neglectful mothers
[64]	León et al. (2021)	Child age: neglectful: M = 2.7 years, SD =1.5; control group M = 2.3 years, SD = 1.9 Mother age: neglectful M = 29.1 years, SD = 7.1; control group M = 33.6, SD = 3.2	45 mother–child dyads (24 neglectful and 21 non-neglectful control mothers)	Mothers with history of neglect of a child in the last 12 months and complied with the indicators of the maltreatment classification system for severe neglect	Mother–child free play; EA scales: six subscales of adult and child EA scales	Mini international neuropsychiatric interview; T1-weighted magnetic resonance imaging with the MPRAGE (magnetization prepared rapid acquisition gradient echo): cortical thickness and surface area	Inter-rater reliability: sensitivity (0.94), structuring (0.90), nonhostility (0.92), nonintrusiveness (0.87), responsiveness (0.92), and involvement (0.86)	Neglectful mothers showed less cortical thickness in the right rostral middle frontal gyrus and a greater surface area in the right lingual and lateral occipital cortices compared to non-neglectful mother; less right rostral middle frontal gyrus thickness, which relates to a lower level of emotional awareness among neglectful mothers
[65]	Rodrigo et al. (2016)	Child age: neglectful group M = 2.5 years Control group M = 2.3 years Mother age: both groups M = 30 years	44 mother–child dyads (2 neglectful and 22 control)	Mothers with history of neglect of a child less than 5 years of age in the last 12 months, referral recorded by Child Protective Services	Mother–child free play; EA scales: six subscales of adult and child EA scales	Mini mental state examination; mini international neuro-psychiatric review; T1-General Electric 3T scanner	Inter-rater reliability: sensitivity (0.94) structuring (0.90) nonintrusiveness (0.87) nonhostility (0.92) responsiveness (0.92) involvement (0.86)	Neglectful mothers, compared to the control, had disruptions in the structural organization of connectors between the occipital lobe and the temporal and frontal lobes: ILF-R and bilaterally the inferior fronto-occipital fasciculi (IFO-R and IFO-L). Neglectful mothers, compared to controls, showed reduced volumes in ILF-R and IFO-L. Positive mother–child interactions were predicted by increased volume in the ILF-R; neglectful mothers had a higher likelihood of exposure to early adversity, higher vulnerability to psychopathologies, and lower cognitive integrity compared to the control
[66]	Olsavsky et al. (2019)	Mother age: 18–40 years	46 mother–infant dyads (28 childhood maltreatment-exposed and 18 non childhood maltreatment-exposed)	Mothers with childhood maltreatment experiences; first-time mothers	15-min mother–infant free play observation; EA scales: maternal sensitivity, maternal structuring, maternal noninstrusiveness, and maternal nonhostility (focused on maternal sensitivity)	Risky family questionnaire; infant face task; functional MRI: amygdala reactivity	ICC = 0.84	Mothers reporting more childhood maltreatment experiences had greater bilateral amygdala reactivity to infant faces compared to mothers who did not experience childhood maltreatment (observation not exhibited when the childhood maltreatment-exposed mothers were shown adult faces)
[67]	Olsavsky et al. (2021)	Mother age: 18–40 years	61 mothers with childhood maltreatment experiences	Mothers with childhood maltreatment experiences; 18–40 years old; one-time mothers	15-min mother–infant behavioral observations; EA scales: focused on maternal sensitivity, maternal noninstrusiveness, and maternal nonhostility	Risky family questionnaire; infant cry paradigm; functional MRI: amygdala reactivity psychophysiological interaction analyses	ICC = 0.84	Mothers reporting more childhood maltreatment experiences had greater bilateral amygdala response to their own infant’s cry compared to other infant’s cry or white noise; mothers with higher amygdala activation may have decreased intrusive behaviors
[68]	Neukel et al. (2017)	Child age: 7–11 years	47 mother–child dyads (22 mothers with a history of physical and/or sexual childhood abuse and 25 without)	Mothers with a history of physical and/or sexual childhood abuse	Mother–child free play; EA scales: six subscales of adult and child EA scales	Childhood experience of care and abuse interview; structured clinical interview for DSM-IV axis I; international personality disorder examination; Hamilton rating scale for depression; functional MRI	Not specified	Mothers with history of physical and/or sexual abuse or neglect showed greater activation in amygdala, insula and hippocampus; showed less functional connectivity between regions of salience and mentalizing network; mothers with history of physical and/or sexual abuse showed higher maternal sensitivity related to greater bilateral insula and amygdala activations to conflictual versus pleasant interactions
[69]	Mielke et al. (2016)	Mother with early life maltreatment (ELM): M = 38.8 years, SD = 6.7 Mother without ELM: M = 39.1 years, SD = 4.5	25 mother–child dyads with ELM and 28 mother-child dyads without ELM	Mothers are absent of any known substance abuse or neurological disease or dementia or severe physical impairments, or any contraindications for MRI measurements	15-min mother–child free play and 6-min problem-solving task; EA scales: maternal sensitivity	Interpersonal reactivity index; structural magnetic resonance imaging with unbiased voxel-based morphometry	Inter-rate reliability: good Cronbach alpha (0.81–0.88)	Mothers with ELM were less sensitive when interacting with their own child, compared to mothers without ELM; for mothers with ELM, maternal sensitivity was positively associated with the volumes of left superior frontal gyrus extending to the superior medial frontal gyrus and middle frontal gyrus, core regions of the cognitive empathy network; maternal sensitivity was negatively associated with the volume of posterior cingulate cortex
[70]	Firk et al. (2018)	Mother age: M = 27 years SD = 5.3	26 mother–infant dyads	Healthy full-term infants, mothers without any genetic syndrome or severe disease	12-min mother–infant free play, EA scales: maternal sensitivity, maternal nonhostility, and maternal nonintrusiveness	Functional MRI; infant cry stimuli	Interrater agreement: maternal sensitivity (0.96), maternal nonhostility (0.94), and maternal nonintrusiveness (0.92)	Higher maternal sensitivity and higher maternal nonhostility were associated with lower amygdala activation during mother–infant interaction; self-distraction decreased subjective emotional intensity and bilateral activations in the amygdala
[71]	Kim et al., (2017)	Mother age: M = 24.41 SD = 5.22	39 mother–child dyads	First-time new mothers in metro Denver areas recruited from midwifery clinics, Women Infant and Children (WIC) and Colorado State Prenatal Plus programs 46% of sample lived in poverty or near poverty (as determined by an income-to-needs ratio <1 or <2)	Mother–child 15-min free-play was observed and coded using the EA 4th edition scales	Beck depression inventory;	Interrater reliability, ICC = 0.713	Socioeconomic disadvantage was associated with neural sensitivity to infant positive and negative emotions. Lower income-to-needs (ITN) ratio was correlated to reduced responses to positive infant faces. There was evidence of elevated amygdala responses related to negative infant faces. Heightened responses to infant faces was associated with mothers’ intrusiveness.
[72]	Schneider-Hassloff, Zwonitzer, Kunster, Mayer, Ziegenhain and Kiefer [72] (2016)	Mother age: M = 39 years SD = 4.0 Child age: M = 58.7 months, SD = 6.6	27 mother–child dyads	Children absent of any known psychiatric or neurological disease or severe developmental delay	20-min mother–child free play; EA scales: six subscales of adult and child EA scales and EA zones	Head-toes-knees-shoulders task; delay of gratification task; strengths and difficulties questionnaire; colored progressive matrices task	Inter-rater reliability: good (ICC > 0.89) for adult structuring, adult nonintrusiveness, adult nonhostility, child responsiveness, and child involvement; inter-rater reliability: acceptable for adult sensitivity (ICC = 0.67), inter-rater reliability: low for EA CS (ICC = 0.55)	Higher EA nonintrusiveness was associated with the behavioral aspects of executive functioning; maternal structuring and nonintrusiveness were associated with electrophysiological correlates of EF
[73]	Licata et al. (2015)	Child age: accessed at 7, 14 and 50 months Final sample M = 6.95 months, SD = 0.22	Sample of 28 children (15 girls)	Mothers diagnosed with postpartum depression and/or anxiety disorders	EA scales, 10-min videotaped interaction, only maternal sensitivity, maternal structuring, child responsiveness and child involvement subscales were used	Vulnerable attachment style questionnaire; structured clinical interview; theory of mind	At 7 months of child’s age: inter-rater reliability maternal sensitivity (0.89), child responsiveness (0.88), and child involvement (0.78) At 50 months of child’s age: maternal sensitivity (0.85), child responsiveness (0.84), and child involvement (0.89)	Low maternal attachment style insecurity and high theory of mind skills predict maternal EA sensitivity
[74]	Killeen & Teti (2012)	Mother age: M = 30.7 yearsInfant age: M = 6.94 months	27 mother–infant dyads	Right-handed mothers	30-min mother–infant free play; EA scales: maternal sensitivity, maternal structuring, maternal nonintrusiveness, maternal nonhostility, child responsiveness, and child involvement	Electroencephalogram; infant emotion videos; SCL-90-R depression and anxiety subscales; maternal self-reported emotional experience	ICC: 0.668–0.738 for maternal sensitivity, maternal structuring, maternal nonintrusiveness, child responsiveness, and child involvement, 0.411 for maternal nonhostility	EA or mother-reported emotional experience in response to infant emotion cues was not related to the greater relative right frontal activity at rest; greater mother–infant EA was associated with a shift toward greater relative right frontal activation in response to infant emotion cues
[75]	Taylor-Colls & Fearon (2015)	Child age: 7 month old (24 males)	40 mother-child dyads	Healthy infants’ absence of low birth weight or premature birth	3-min mother–child free play; EA scales: maternal sensitivity, maternal structuring, maternal noninstrusiveness, and maternal nonhostility	Event-related potentials; infant behavior questionnaire	Inter-rater reliability: reasonable (ICC = 0.71–0.75)	Higher maternal sensitivity was related to infants’ greater amplitudes to positive facial expressions, relative to fearful and neutral expressions.