A MIXED METHODS LONGITUDINAL STUDY: EXAMINING HOW THE HOME ENVIRONMENT SHAPES INFANT FEEDING AND LANGUAGE DEVELOPMENT
NIH-Funded Graduate Research at Northeastern University's Speech and Neurodevelopment Lab
Northeastern's Speech & Neurodevelopment Lab (SNL) is an NIH-funded research lab studying how sucking, feeding, and early language develop together in infancy. As Graduate Researcher and Co-author, I designed and executed a mixed methods longitudinal study - conducting in-home visits with 132 infants, surveying 307 early intervention SLPs, and analyzing data in SPSS - resulting in two peer-reviewed publications and a clinical roadmap for how the home environment shapes child development in the first year of life.
Overview
MY ROLE:
Graduate Researcher & Co-author
LAB:
Speech & Neurodevelopment Lab, Northeastern University
FUNDING:
NIH R21DC016030
PARTICIPANTS:
74 infants (3 months) · 58 infants (12 months) · 307 SLPs surveyed
DURATION:
2018 - 2020
PRESENTED:
RISE Symposium 2019 · ASHA National Conference 2019
PUBLISHED:
Midwifery 2023 · Pediatric Medicine 2022
DATA COLLECTION TOOLS:
Qualtrics · LENA · Non-nutritive suck device · Assessments (Neo-EAT, Pedi-EAT, OFS)
STATISTICAL ANALYSIS:
SPSS · Shapiro-Wilk · Spearman Correlation
COMMUNICATING INSIGHTS:
Academic Publishing· Poster Design · Conference Presentation
SECTION 1
Background
my why
As a graduate student, I was drawn to infant feeding because I wanted to work in hospitals, supporting families navigating some of the scariest moments of their lives. A premature baby in the NICU. A mom struggling to feed her newborn. A family without answers.
I wanted to understand: Why do infants struggle with feeding? How can we help them? And how can we help the clinicians supporting these families too?
That curiosity led me to the Speech & Neurodevelopment Lab (SNL) at Northeastern - led by Dr. Emily Zimmerman, one of the only researchers in the country studying how sucking, feeding, and early language develop together. I joined as a graduate researcher in 2018, and it's where this study came to life.
Members of the Speech & Neurodevelopment Lab, 2018–2020 - pictured with the Soothie pacifiers used in our studies.
a gap in literature
Research consistently shows that both feeding and language development in infancy are shaped by the home environment:
The quality and amount of language a baby hears at home shapes how their vocabulary grows
Back-and-forth conversations between adults and babies directly shape language development
How caregivers respond during feeding affects how babies learn to self-regulate
A stimulating home environment supports how babies think and communicate
However, to our knowledge, no one has ever studied feeding, language development, and the home environment all together.
SECTION 2
Research questions
What we set out to answer
With the gap identified, we needed the right questions. These three aims shaped every research and methodological decision that followed:
AIM 1:
How do IT-HOME subscales relate to language exposure (measured by LENA device) at 3 and 12 months?
AIM 2:
How do IT-HOME subscales relate to infant feeding outcomes at 3 and 12 months?
AIM 3:
What do practicing SLPs believe about the home environment's role in early intervention - and are they actually acting on those beliefs?
why this matters
Understanding these connections helps us support child development more effectively - and gives parents meaningful guidance on the decisions that shape their baby's first year.
SECTION 3
methods
This study was conducted in two phases, each designed to answer a different set of research questions:
PHASE I
Longitudinal Observational Study
Home visits with full-term infants at 3 and 12 months of age
PHASE II
Speech-Language Pathologist (SLP) Survey
A national Qualtrics survey of 307 early intervention SLPs
PHASE I & II
How the Findings Interact
Connecting home environment data with SLP clinical practice
PHASE II
SLP Survey
A national Qualtrics survey of 307 early intervention SLPs
Phase I: Longitudinal observational study
Data for Phase I comes from a larger ongoing study examining the relationship between sucking, oral feeding, and vocal development in full-term infants. Home visits were conducted at 3 months and again at 12 months.
Families received an Amazon gift card for participating - $50 at the 3-month visit and $100 at 12 months.
What happened during a visit
We entered the family's home, set up our equipment, and completed the following:
Non-Nutritive Suck (NNS) Assessment
Infant sucked on a custom research pacifier connected to a pressure transducer system and ADInstruments PowerLab for 5 minutes. LabChart Pro software analyzed the suck dynamics.
Measured:
NNS Amplitude · NNS Cycles/min · NNS Cycles/burst · NNS Frequency (Hz) · NNS Bursts/min
Oral Feeding Skills (OFS)
Researcher observed and recorded a full bottle feed to assess the infant's oral feeding skills.
Measured:
Initial bottle intake (ml) · Transfer rate (ml/min) · Transfer volume (% volume) · Feeding proficiency
Feeding Questionnaire - parent report
Caregiver completed a standardized feeding questionnaire while the researcher was present.
Measured:
Neo-EAT ( administered 3 months) · Pedi-EAT (administered at 12 months)
LENA — language environment recording
Infant was fitted with a vest containing a Digital Language Processor worn for 12 hours to record the naturalistic language environment. Parents kept an hourly activity log.
Measured:
Child Vocalization Count (CVC) · Adult Word Count (AWC) · Conversational Turn Count (CTC) · Percent Time Vocalized
IT-HOME Inventory
Researcher completed the 45-item Infant-Toddler HOME Inventory through observation and interview questions.
Subscales:
Responsivity · Acceptance · Organization · Learning Materials · Involvement · Variety of Daily Stimulation
Phase II: SLP Survey
The purpose of Phase II was to understand what clinicians actually knew - and did - when it came to the home environment.
survey design
An electronic survey was designed and launched via Qualtrics, distributed to early intervention SLPs through online Facebook forums. The survey consisted of 34 questions and took approximately 5 minutes to complete. Launched August 2019, closed January 2020. Participants were entered in a raffle to win a $50 Amazon gift card.
SECTION 4
Participants
Phase I: Longitudinal observational study
3 MONTHS
74
infants
51.4% male · Average age 2.97 months
90.5% no family history of speech-language issues
Majority Caucasian caregivers, primarily English-speaking
~66% of caregivers held graduate degrees
12 MONTHS
58
infants
30 male · Average age 11.87 months
Similar demographic profile to 3-month cohort
94.5% no family history of speech-language issues
~72% of caregivers held graduate degrees
Inclusion Criteria: Infants were included in this study if they were enrolled in the larger, ongoing study in the lab · Full-term birth (≥37 weeks gestation)
Phase II: SLP Survey
SLPs ranged from under 5 years to over 20 years of experience
0
0
Total responses recieved
0
0
Final sample after exclusions
0%
0%
Worked in home environment
Inclusion Criteria: To be included, participants were required to hold ASHA certification, provide consent to participate, and complete 100% of the survey
SECTION 5
Results
Phase I: Longitudinal observational study
Key findings
Spearman correlations revealed significant associations between specific IT-HOME subscales and infant feeding and language outcomes at both time points.
AT 3 MONTHS
IT-HOME Involvement -
IT-HOME Involvement
Positively associated with NNS Burst and OFS Initial. More involved caregivers had infants with stronger sucking patterns and better bottle intake.
rs=.354, p=.003 · rs=.329, p=.015
IT-HOME Variety -
IT-HOME Variety
Positively associated with OFS Transfer Volume and Transfer Rate. More varied home stimulation linked to better feeding efficiency.
rs=.543, p<.001 · rs=.289, p=.040
IT-HOME Acceptance -
IT-HOME Acceptance
Negatively associated with Neo-EAT Bottle Stability and Total. More accepting caregivers reported fewer feeding difficulties.
rs=-.290, p=.039 · rs=-.353, p=.019
IT-HOME Organization -
IT-HOME Organization
Positively associated with Child Vocalization, Conversational Turn Count, and Percent Time Vocalized. More regulated homes had more vocal infants.
rs=.254, p=.043 · rs=.265, p=.034 · rs=.293, p=.019
AT 12 MONTHS
IT-HOME Organization -
Negatively associated with PediEAT Physiology, Mealtime Behavior, Selective Eating, and Total. More regulated homes had fewer feeding difficulties at 12 months.
rs=-.281, p=.042 · rs=-.347, p=.012 · rs=-.313, p=.027 · rs=-.387, p=.006
IT-HOME Acceptance -
Positively associated with NNS Frequency. Less restrictive caregiving linked to faster sucking patterns.
rs=.543, p<.001 · rs=.289, p=.040
IT-HOME Acceptance -
Negatively associated with Neo-EAT Bottle Stability and Total. More accepting caregivers reported fewer feeding difficulties.
rs=.337, p=.037
IT-HOME Learning Materials -
Positively associated with NNS Cycles/Burst and Child Vocalizations. More stimulating play environments linked to stronger sucking and more vocalizations.
rs=.314, p=.048 · rs=.291, p=.048
Phase II: SLP Survey
What SLPs told us
162 early intervention SLPs completed the survey. What they said revealed a striking gap between knowledge and action.
0%
0%
Believe home environment plays a role in speech & language development
0%
0%
Believe it plays a role in feeding development
THE GAP — KNOWLEDGE VS. ACTION
51.23%
Of SLPs reported to always educate families on the home environment
12 MONTHS
25.31%
Of SLPs reported to always encourage families to actually change their home environment
12 MONTHS
25.31%
Of SLPs reported to always encourage families to actually change their home environment
SLPs know it matters - but most aren't acting on it.
SECTION 5
key Insights
Phase I & II: How the findings interact
What we learned
The home environment shapes both feeding and language development
Specific aspects of the home - how organized it is, how involved caregivers are, what materials are present - consistently predicted feeding and vocalization outcomes at both 3 and 12 months. And the aspects that mattered shifted as infants developed.
SLPs know it matters - but most aren't acting on it
Nearly all SLPs believe the home environment is important for speech-language development. But fewer than 1 in 4 are actively encouraging families to change it. There's no standardized approach - and that gap needs to be addressed.
Context matters - feeding time is underutilized
Research shows parents use more diverse language during feeding than during play - yet most early intervention focuses on play contexts. Mealtime is a missed opportunity for language and bonding that clinicians should be leveraging.
In summary: Different aspects of the home environment influence feeding and vocalizations early in infancy - and as the infant matures, different aspects become important. At 3 months, involvement and variety drive feeding outcomes. At 12 months, organization and learning materials take over.
SLPs know the home environment matters. But fewer than 1 in 4 are actively encouraging families to change it.
This research created a roadmap for when and how clinicians should intervene.
from research to practice - clinical personas
These findings don't just live in a journal - they translate directly into how clinicians should support families. Here's what that looks like in practice.
Baby Sam, 3 months
Presenting with feeding difficulties
WHAT THE RESEARCH TELLS US
At 3 months, IT-HOME Involvement and Acceptance predicted feeding outcomes. Caregiver responsiveness and positive reinforcement during feeding directly shaped how infants fed.
WHAT AN SLP SHOULD DO
Encourage caregivers to respond to hunger cues, educate on developmental milestones, and advocate for positive feeding experiences. A family-centered, multidisciplinary approach is critical at this stage.
Baby Maya, 12 months
Presenting with reduced vocalizations
WHAT THE RESEARCH TELLS US
At 12 months, IT-HOME Learning Materials predicted child vocalizations. Infants with more stimulating toys and play materials vocalized more - the home environment was directly shaping their language development.
WHAT AN SLP SHOULD DO
Advocate for age-appropriate toys and books at home. Teach caregivers how to use these materials to encourage interaction - and support with models, prompts, and feedback so changes actually stick.
WHAT THIS MEANS FOR FUTURE RESEARCH
More research is needed across different home environments and across activities within the same environment. As this study showed, context matters - the same home can provide very different developmental opportunities depending on whether an infant is feeding, playing, or just awake and listening. Future studies should examine these distinctions more closely.
SECTION 7
Reflections
What this research taught me: This was my first experience conducting rigorous mixed methods research from study design through statistical analysis through publication. Running home visits, fitting infants with LENA vests, administering standardized assessments, and analyzing SPSS data - gave me a research foundation I carry into every project I do today.
What I'd do differently: The survey sample (Phase II) was distributed through online SLP forums which may have introduced self-selection bias - SLPs who actively engage in online professional communities may not represent all early intervention practitioners. A more diverse recruitment strategy would strengthen generalizability.
What this means for UX: The same question that drove this research drives my UX work - there's a gap between what people know and what they actually do. Understanding that gap, and designing interventions to close it, is at the core of both clinical research and product research.
SECTION 8
Publications
Peer reviewed publications
This work (my graduate thesis) contributed to two peer-reviewed, NIH-funded publications - both publicly available and searchable:
MIDWIFERY · VOLUME 116 · JANUARY 2023 · NIH FUNDED
The home environment and its relation to bottle feeding outcomes in the first year of life
Martens A, Carpenito T, Hines M, Iizuka A, Aspinwall B, Zimmerman E
PEDIATRIC MEDICINE · 2022 · NIH FUNDED
The home environment and its relation to vocalizations in the first year of life
Hines M, Carpenito T, Martens A, Iizuka A, Aspinwall B, Zimmerman E
conference presentations
ASHA NATIONAL CONFERENCE · 2019
American Speech-Language-Hearing Association
Presented findings on the relationship between the home environment, infant feeding, and vocalizations to a national audience of speech-language pathologists and researchers.
RISE SYMPOSIUM · 2019
Northeastern University Research Symposium
Presented a poster on longitudinal findings connecting IT-HOME subscales to infant feeding and vocalization outcomes at 3 and 12 months.
More Projects
A MIXED METHODS LONGITUDINAL STUDY: EXAMINING HOW THE HOME ENVIRONMENT SHAPES INFANT FEEDING AND LANGUAGE DEVELOPMENT
NIH-Funded Graduate Research at Northeastern University's Speech and Neurodevelopment Lab
Northeastern's Speech & Neurodevelopment Lab (SNL) is an NIH-funded research lab studying how sucking, feeding, and early language develop together in infancy. As Graduate Researcher and Co-author, I designed and executed a mixed methods longitudinal study - conducting in-home visits with 132 infants, surveying 307 early intervention SLPs, and analyzing data in SPSS - resulting in two peer-reviewed publications and a clinical roadmap for how the home environment shapes child development in the first year of life.
Overview
MY ROLE:
Graduate Researcher & Co-author
LAB:
Speech & Neurodevelopment Lab, Northeastern University
FUNDING:
NIH R21DC016030
PARTICIPANTS:
74 infants (3 months) · 58 infants (12 months) · 307 SLPs surveyed
DURATION:
2018 - 2020
PRESENTED:
RISE Symposium 2019 · ASHA National Conference 2019
PUBLISHED:
Midwifery 2023 · Pediatric Medicine 2022
DATA COLLECTION TOOLS:
Qualtrics · LENA · Non-nutritive suck device · Assessments (Neo-EAT, Pedi-EAT, OFS)
STATISTICAL ANALYSIS:
SPSS · Shapiro-Wilk · Spearman Correlation
COMMUNICATING INSIGHTS:
Academic Publishing· Poster Design · Conference Presentation
SECTION 1
Background
my why
As a graduate student, I was drawn to infant feeding because I wanted to work in hospitals, supporting families navigating some of the scariest moments of their lives. A premature baby in the NICU. A mom struggling to feed her newborn. A family without answers.
I wanted to understand: Why do infants struggle with feeding? How can we help them? And how can we help the clinicians supporting these families too?
That curiosity led me to the Speech & Neurodevelopment Lab (SNL) at Northeastern - led by Dr. Emily Zimmerman, one of the only researchers in the country studying how sucking, feeding, and early language develop together. I joined as a graduate researcher in 2018, and it's where this study came to life.
Members of the Speech & Neurodevelopment Lab, 2018–2020 - pictured with the Soothie pacifiers used in our studies.
a gap in literature
Research consistently shows that both feeding and language development in infancy are shaped by the home environment:
The quality and amount of language a baby hears at home shapes how their vocabulary grows
Back-and-forth conversations between adults and babies directly shape language development
How caregivers respond during feeding affects how babies learn to self-regulate
A stimulating home environment supports how babies think and communicate
However, to our knowledge, no one has ever studied feeding, language development, and the home environment all together.
SECTION 2
Research questions
What we set out to answer
With the gap identified, we needed the right questions. These three aims shaped every research and methodological decision that followed:
AIM 1:
How do IT-HOME subscales relate to language exposure (measured by LENA device) at 3 and 12 months?
AIM 2:
How do IT-HOME subscales relate to infant feeding outcomes at 3 and 12 months?
AIM 3:
What do practicing SLPs believe about the home environment's role in early intervention - and are they actually acting on those beliefs?
why this matters
Understanding these connections helps us support child development more effectively - and gives parents meaningful guidance on the decisions that shape their baby's first year.
SECTION 3
methods
This study was conducted in two phases, each designed to answer a different set of research questions:
PHASE I
Longitudinal Observational Study
Home visits with full-term infants at 3 and 12 months of age
PHASE II
Speech-Language Pathologist (SLP) Survey
A national Qualtrics survey of 307 early intervention SLPs
PHASE I & II
How the Findings Interact
Connecting home environment data with SLP clinical practice
PHASE II
SLP Survey
A national Qualtrics survey of 307 early intervention SLPs
Phase I: Longitudinal observational study
Data for Phase I comes from a larger ongoing study examining the relationship between sucking, oral feeding, and vocal development in full-term infants. Home visits were conducted at 3 months and again at 12 months.
Families received an Amazon gift card for participating - $50 at the 3-month visit and $100 at 12 months.
What happened during a visit
We entered the family's home, set up our equipment, and completed the following:
Non-Nutritive Suck (NNS) Assessment
Infant sucked on a custom research pacifier connected to a pressure transducer system and ADInstruments PowerLab for 5 minutes. LabChart Pro software analyzed the suck dynamics.
Measured:
NNS Amplitude · NNS Cycles/min · NNS Cycles/burst · NNS Frequency (Hz) · NNS Bursts/min
Oral Feeding Skills (OFS)
Researcher observed and recorded a full bottle feed to assess the infant's oral feeding skills.
Measured:
Initial bottle intake (ml) · Transfer rate (ml/min) · Transfer volume (% volume) · Feeding proficiency
Feeding Questionnaire - parent report
Caregiver completed a standardized feeding questionnaire while the researcher was present.
Measured:
Neo-EAT ( administered 3 months) · Pedi-EAT (administered at 12 months)
LENA — language environment recording
Infant was fitted with a vest containing a Digital Language Processor worn for 12 hours to record the naturalistic language environment. Parents kept an hourly activity log.
Measured:
Child Vocalization Count (CVC) · Adult Word Count (AWC) · Conversational Turn Count (CTC) · Percent Time Vocalized
IT-HOME Inventory
Researcher completed the 45-item Infant-Toddler HOME Inventory through observation and interview questions.
Subscales:
Responsivity · Acceptance · Organization · Learning Materials · Involvement · Variety of Daily Stimulation
Phase II: SLP Survey
The purpose of Phase II was to understand what clinicians actually knew - and did - when it came to the home environment.
survey design
An electronic survey was designed and launched via Qualtrics, distributed to early intervention SLPs through online Facebook forums. The survey consisted of 34 questions and took approximately 5 minutes to complete. Launched August 2019, closed January 2020. Participants were entered in a raffle to win a $50 Amazon gift card.
SECTION 4
Participants
Phase I: Longitudinal observational study
3 MONTHS
74
infants
51.4% male · Average age 2.97 months
90.5% no family history of speech-language issues
Majority Caucasian caregivers, primarily English-speaking
~66% of caregivers held graduate degrees
12 MONTHS
58
infants
30 male · Average age 11.87 months
Similar demographic profile to 3-month cohort
94.5% no family history of speech-language issues
~72% of caregivers held graduate degrees
Inclusion Criteria: Infants were included in this study if they were enrolled in the larger, ongoing study in the lab · Full-term birth (≥37 weeks gestation)
Phase II: SLP Survey
SLPs ranged from under 5 years to over 20 years of experience
0
0
Total responses recieved
0
0
Final sample after exclusions
0%
0%
Worked in home environment
Inclusion Criteria: To be included, participants were required to hold ASHA certification, provide consent to participate, and complete 100% of the survey
SECTION 5
Results
Phase I: Longitudinal observational study
Key findings
Spearman correlations revealed significant associations between specific IT-HOME subscales and infant feeding and language outcomes at both time points.
AT 3 MONTHS
IT-HOME Involvement -
IT-HOME Involvement
Positively associated with NNS Burst and OFS Initial. More involved caregivers had infants with stronger sucking patterns and better bottle intake.
rs=.354, p=.003 · rs=.329, p=.015
IT-HOME Variety -
IT-HOME Variety
Positively associated with OFS Transfer Volume and Transfer Rate. More varied home stimulation linked to better feeding efficiency.
rs=.543, p<.001 · rs=.289, p=.040
IT-HOME Acceptance -
IT-HOME Acceptance
Negatively associated with Neo-EAT Bottle Stability and Total. More accepting caregivers reported fewer feeding difficulties.
rs=-.290, p=.039 · rs=-.353, p=.019
IT-HOME Organization -
IT-HOME Organization
Positively associated with Child Vocalization, Conversational Turn Count, and Percent Time Vocalized. More regulated homes had more vocal infants.
rs=.254, p=.043 · rs=.265, p=.034 · rs=.293, p=.019
AT 12 MONTHS
IT-HOME Organization -
Negatively associated with PediEAT Physiology, Mealtime Behavior, Selective Eating, and Total. More regulated homes had fewer feeding difficulties at 12 months.
rs=-.281, p=.042 · rs=-.347, p=.012 · rs=-.313, p=.027 · rs=-.387, p=.006
IT-HOME Acceptance -
Positively associated with NNS Frequency. Less restrictive caregiving linked to faster sucking patterns.
rs=.543, p<.001 · rs=.289, p=.040
IT-HOME Acceptance -
Negatively associated with Neo-EAT Bottle Stability and Total. More accepting caregivers reported fewer feeding difficulties.
rs=.337, p=.037
IT-HOME Learning Materials -
Positively associated with NNS Cycles/Burst and Child Vocalizations. More stimulating play environments linked to stronger sucking and more vocalizations.
rs=.314, p=.048 · rs=.291, p=.048
Phase II: SLP Survey
What SLPs told us
162 early intervention SLPs completed the survey. What they said revealed a striking gap between knowledge and action.
0%
0%
Believe home environment plays a role in speech & language development
0%
0%
Believe it plays a role in feeding development
THE GAP — KNOWLEDGE VS. ACTION
51.23%
Of SLPs reported to always educate families on the home environment
12 MONTHS
25.31%
Of SLPs reported to always encourage families to actually change their home environment
12 MONTHS
25.31%
Of SLPs reported to always encourage families to actually change their home environment
SLPs know it matters - but most aren't acting on it.
SECTION 5
key Insights
Phase I & II: How the findings interact
What we learned
The home environment shapes both feeding and language development
Specific aspects of the home - how organized it is, how involved caregivers are, what materials are present - consistently predicted feeding and vocalization outcomes at both 3 and 12 months. And the aspects that mattered shifted as infants developed.
SLPs know it matters - but most aren't acting on it
Nearly all SLPs believe the home environment is important for speech-language development. But fewer than 1 in 4 are actively encouraging families to change it. There's no standardized approach - and that gap needs to be addressed.
Context matters - feeding time is underutilized
Research shows parents use more diverse language during feeding than during play - yet most early intervention focuses on play contexts. Mealtime is a missed opportunity for language and bonding that clinicians should be leveraging.
In summary: Different aspects of the home environment influence feeding and vocalizations early in infancy - and as the infant matures, different aspects become important. At 3 months, involvement and variety drive feeding outcomes. At 12 months, organization and learning materials take over.
SLPs know the home environment matters. But fewer than 1 in 4 are actively encouraging families to change it.
This research created a roadmap for when and how clinicians should intervene.
from research to practice - clinical personas
These findings don't just live in a journal - they translate directly into how clinicians should support families. Here's what that looks like in practice.
Baby Sam, 3 months
Presenting with feeding difficulties
WHAT THE RESEARCH TELLS US
At 3 months, IT-HOME Involvement and Acceptance predicted feeding outcomes. Caregiver responsiveness and positive reinforcement during feeding directly shaped how infants fed.
WHAT AN SLP SHOULD DO
Encourage caregivers to respond to hunger cues, educate on developmental milestones, and advocate for positive feeding experiences. A family-centered, multidisciplinary approach is critical at this stage.
Baby Maya, 12 months
Presenting with reduced vocalizations
WHAT THE RESEARCH TELLS US
At 12 months, IT-HOME Learning Materials predicted child vocalizations. Infants with more stimulating toys and play materials vocalized more - the home environment was directly shaping their language development.
WHAT AN SLP SHOULD DO
Advocate for age-appropriate toys and books at home. Teach caregivers how to use these materials to encourage interaction - and support with models, prompts, and feedback so changes actually stick.
WHAT THIS MEANS FOR FUTURE RESEARCH
More research is needed across different home environments and across activities within the same environment. As this study showed, context matters - the same home can provide very different developmental opportunities depending on whether an infant is feeding, playing, or just awake and listening. Future studies should examine these distinctions more closely.
SECTION 7
Reflections
What this research taught me: This was my first experience conducting rigorous mixed methods research from study design through statistical analysis through publication. Running home visits, fitting infants with LENA vests, administering standardized assessments, and analyzing SPSS data - gave me a research foundation I carry into every project I do today.
What I'd do differently: The survey sample (Phase II) was distributed through online SLP forums which may have introduced self-selection bias - SLPs who actively engage in online professional communities may not represent all early intervention practitioners. A more diverse recruitment strategy would strengthen generalizability.
What this means for UX: The same question that drove this research drives my UX work - there's a gap between what people know and what they actually do. Understanding that gap, and designing interventions to close it, is at the core of both clinical research and product research.
SECTION 8
Publications
Peer reviewed publications
This work (my graduate thesis) contributed to two peer-reviewed, NIH-funded publications - both publicly available and searchable:
MIDWIFERY · VOLUME 116 · JANUARY 2023 · NIH FUNDED
The home environment and its relation to bottle feeding outcomes in the first year of life
Martens A, Carpenito T, Hines M, Iizuka A, Aspinwall B, Zimmerman E
PEDIATRIC MEDICINE · 2022 · NIH FUNDED
The home environment and its relation to vocalizations in the first year of life
Hines M, Carpenito T, Martens A, Iizuka A, Aspinwall B, Zimmerman E
conference presentations
ASHA NATIONAL CONFERENCE · 2019
American Speech-Language-Hearing Association
Presented findings on the relationship between the home environment, infant feeding, and vocalizations to a national audience of speech-language pathologists and researchers.
RISE SYMPOSIUM · 2019
Northeastern University Research Symposium
Presented a poster on longitudinal findings connecting IT-HOME subscales to infant feeding and vocalization outcomes at 3 and 12 months.
More Projects
A MIXED METHODS LONGITUDINAL STUDY: EXAMINING HOW THE HOME ENVIRONMENT SHAPES INFANT FEEDING AND LANGUAGE DEVELOPMENT
NIH-Funded Graduate Research at Northeastern University's Speech and Neurodevelopment Lab
Northeastern's Speech & Neurodevelopment Lab (SNL) is an NIH-funded research lab studying how sucking, feeding, and early language develop together in infancy. As Graduate Researcher and Co-author, I designed and executed a mixed methods longitudinal study - conducting in-home visits with 132 infants, surveying 307 early intervention SLPs, and analyzing data in SPSS - resulting in two peer-reviewed publications and a clinical roadmap for how the home environment shapes child development in the first year of life.
Overview
MY ROLE:
Graduate Researcher & Co-author
LAB:
Speech & Neurodevelopment Lab, Northeastern University
FUNDING:
NIH R21DC016030
PARTICIPANTS:
74 infants (3 months) · 58 infants (12 months) · 307 SLPs surveyed
DURATION:
2018 - 2020
PRESENTED:
RISE Symposium 2019 · ASHA National Conference 2019
PUBLISHED:
Midwifery 2023 · Pediatric Medicine 2022
DATA COLLECTION TOOLS:
Qualtrics · LENA · Non-nutritive suck device · Assessments (Neo-EAT, Pedi-EAT, OFS)
STATISTICAL ANALYSIS:
SPSS · Shapiro-Wilk · Spearman Correlation
COMMUNICATING INSIGHTS:
Academic Publishing· Poster Design · Conference Presentation
SECTION 1
Background
my why
As a graduate student, I was drawn to infant feeding because I wanted to work in hospitals, supporting families navigating some of the scariest moments of their lives. A premature baby in the NICU. A mom struggling to feed her newborn. A family without answers.
I wanted to understand: Why do infants struggle with feeding? How can we help them? And how can we help the clinicians supporting these families too?
That curiosity led me to the Speech & Neurodevelopment Lab (SNL) at Northeastern - led by Dr. Emily Zimmerman, one of the only researchers in the country studying how sucking, feeding, and early language develop together. I joined as a graduate researcher in 2018, and it's where this study came to life.
Members of the Speech & Neurodevelopment Lab, 2018–2020 - pictured with the Soothie pacifiers used in our studies.
a gap in literature
Research consistently shows that both feeding and language development in infancy are shaped by the home environment:
The quality and amount of language a baby hears at home shapes how their vocabulary grows
Back-and-forth conversations between adults and babies directly shape language development
How caregivers respond during feeding affects how babies learn to self-regulate
A stimulating home environment supports how babies think and communicate
However, to our knowledge, no one has ever studied feeding, language development, and the home environment all together.
SECTION 2
Research questions
What we set out to answer
With the gap identified, we needed the right questions. These three aims shaped every research and methodological decision that followed:
AIM 1:
How do IT-HOME subscales relate to language exposure (measured by LENA device) at 3 and 12 months?
AIM 2:
How do IT-HOME subscales relate to infant feeding outcomes at 3 and 12 months?
AIM 3:
What do practicing SLPs believe about the home environment's role in early intervention - and are they actually acting on those beliefs?
why this matters
Understanding these connections helps us support child development more effectively - and gives parents meaningful guidance on the decisions that shape their baby's first year.
SECTION 3
methods
This study was conducted in two phases, each designed to answer a different set of research questions:
PHASE I
Longitudinal Observational Study
Home visits with full-term infants at 3 and 12 months of age
PHASE II
Speech-Language Pathologist (SLP) Survey
A national Qualtrics survey of 307 early intervention SLPs
PHASE I & II
How the Findings Interact
Connecting home environment data with SLP clinical practice
PHASE II
SLP Survey
A national Qualtrics survey of 307 early intervention SLPs
Phase I: Longitudinal observational study
Data for Phase I comes from a larger ongoing study examining the relationship between sucking, oral feeding, and vocal development in full-term infants. Home visits were conducted at 3 months and again at 12 months.
Families received an Amazon gift card for participating - $50 at the 3-month visit and $100 at 12 months.
What happened during a visit
We entered the family's home, set up our equipment, and completed the following:
Non-Nutritive Suck (NNS) Assessment
Infant sucked on a custom research pacifier connected to a pressure transducer system and ADInstruments PowerLab for 5 minutes. LabChart Pro software analyzed the suck dynamics.
Measured:
NNS Amplitude · NNS Cycles/min · NNS Cycles/burst · NNS Frequency (Hz) · NNS Bursts/min
Oral Feeding Skills (OFS)
Researcher observed and recorded a full bottle feed to assess the infant's oral feeding skills.
Measured:
Initial bottle intake (ml) · Transfer rate (ml/min) · Transfer volume (% volume) · Feeding proficiency
Feeding Questionnaire - parent report
Caregiver completed a standardized feeding questionnaire while the researcher was present.
Measured:
Neo-EAT ( administered 3 months) · Pedi-EAT (administered at 12 months)
LENA — language environment recording
Infant was fitted with a vest containing a Digital Language Processor worn for 12 hours to record the naturalistic language environment. Parents kept an hourly activity log.
Measured:
Child Vocalization Count (CVC) · Adult Word Count (AWC) · Conversational Turn Count (CTC) · Percent Time Vocalized
IT-HOME Inventory
Researcher completed the 45-item Infant-Toddler HOME Inventory through observation and interview questions.
Subscales:
Responsivity · Acceptance · Organization · Learning Materials · Involvement · Variety of Daily Stimulation
Phase II: SLP Survey
The purpose of Phase II was to understand what clinicians actually knew - and did - when it came to the home environment.
survey design
An electronic survey was designed and launched via Qualtrics, distributed to early intervention SLPs through online Facebook forums. The survey consisted of 34 questions and took approximately 5 minutes to complete. Launched August 2019, closed January 2020. Participants were entered in a raffle to win a $50 Amazon gift card.
SECTION 4
Participants
Phase I: Longitudinal observational study
3 MONTHS
74
infants
51.4% male · Average age 2.97 months
90.5% no family history of speech-language issues
Majority Caucasian caregivers, primarily English-speaking
~66% of caregivers held graduate degrees
12 MONTHS
58
infants
30 male · Average age 11.87 months
Similar demographic profile to 3-month cohort
94.5% no family history of speech-language issues
~72% of caregivers held graduate degrees
Inclusion Criteria: Infants were included in this study if they were enrolled in the larger, ongoing study in the lab · Full-term birth (≥37 weeks gestation)
Phase II: SLP Survey
SLPs ranged from under 5 years to over 20 years of experience
0
0
Total responses recieved
0
0
Final sample after exclusions
0%
0%
Worked in home environment
Inclusion Criteria: To be included, participants were required to hold ASHA certification, provide consent to participate, and complete 100% of the survey
SECTION 5
Results
Phase I: Longitudinal observational study
Key findings
Spearman correlations revealed significant associations between specific IT-HOME subscales and infant feeding and language outcomes at both time points.
AT 3 MONTHS
IT-HOME Involvement -
IT-HOME Involvement
Positively associated with NNS Burst and OFS Initial. More involved caregivers had infants with stronger sucking patterns and better bottle intake.
rs=.354, p=.003 · rs=.329, p=.015
IT-HOME Variety -
IT-HOME Variety
Positively associated with OFS Transfer Volume and Transfer Rate. More varied home stimulation linked to better feeding efficiency.
rs=.543, p<.001 · rs=.289, p=.040
IT-HOME Acceptance -
IT-HOME Acceptance
Negatively associated with Neo-EAT Bottle Stability and Total. More accepting caregivers reported fewer feeding difficulties.
rs=-.290, p=.039 · rs=-.353, p=.019
IT-HOME Organization -
IT-HOME Organization
Positively associated with Child Vocalization, Conversational Turn Count, and Percent Time Vocalized. More regulated homes had more vocal infants.
rs=.254, p=.043 · rs=.265, p=.034 · rs=.293, p=.019
AT 12 MONTHS
IT-HOME Organization -
Negatively associated with PediEAT Physiology, Mealtime Behavior, Selective Eating, and Total. More regulated homes had fewer feeding difficulties at 12 months.
rs=-.281, p=.042 · rs=-.347, p=.012 · rs=-.313, p=.027 · rs=-.387, p=.006
IT-HOME Acceptance -
Positively associated with NNS Frequency. Less restrictive caregiving linked to faster sucking patterns.
rs=.543, p<.001 · rs=.289, p=.040
IT-HOME Acceptance -
Negatively associated with Neo-EAT Bottle Stability and Total. More accepting caregivers reported fewer feeding difficulties.
rs=.337, p=.037
IT-HOME Learning Materials -
Positively associated with NNS Cycles/Burst and Child Vocalizations. More stimulating play environments linked to stronger sucking and more vocalizations.
rs=.314, p=.048 · rs=.291, p=.048
Phase II: SLP Survey
What SLPs told us
162 early intervention SLPs completed the survey. What they said revealed a striking gap between knowledge and action.
0%
0%
Believe home environment plays a role in speech & language development
0%
0%
Believe it plays a role in feeding development
THE GAP — KNOWLEDGE VS. ACTION
51.23%
Of SLPs reported to always educate families on the home environment
12 MONTHS
25.31%
Of SLPs reported to always encourage families to actually change their home environment
12 MONTHS
25.31%
Of SLPs reported to always encourage families to actually change their home environment
SLPs know it matters - but most aren't acting on it.
SECTION 5
key Insights
Phase I & II: How the findings interact
What we learned
The home environment shapes both feeding and language development
Specific aspects of the home - how organized it is, how involved caregivers are, what materials are present - consistently predicted feeding and vocalization outcomes at both 3 and 12 months. And the aspects that mattered shifted as infants developed.
SLPs know it matters - but most aren't acting on it
Nearly all SLPs believe the home environment is important for speech-language development. But fewer than 1 in 4 are actively encouraging families to change it. There's no standardized approach - and that gap needs to be addressed.
Context matters - feeding time is underutilized
Research shows parents use more diverse language during feeding than during play - yet most early intervention focuses on play contexts. Mealtime is a missed opportunity for language and bonding that clinicians should be leveraging.
In summary: Different aspects of the home environment influence feeding and vocalizations early in infancy - and as the infant matures, different aspects become important. At 3 months, involvement and variety drive feeding outcomes. At 12 months, organization and learning materials take over.
SLPs know the home environment matters. But fewer than 1 in 4 are actively encouraging families to change it.
This research created a roadmap for when and how clinicians should intervene.
from research to practice - clinical personas
These findings don't just live in a journal - they translate directly into how clinicians should support families. Here's what that looks like in practice.
Baby Sam, 3 months
Presenting with feeding difficulties
WHAT THE RESEARCH TELLS US
At 3 months, IT-HOME Involvement and Acceptance predicted feeding outcomes. Caregiver responsiveness and positive reinforcement during feeding directly shaped how infants fed.
WHAT AN SLP SHOULD DO
Encourage caregivers to respond to hunger cues, educate on developmental milestones, and advocate for positive feeding experiences. A family-centered, multidisciplinary approach is critical at this stage.
Baby Maya, 12 months
Presenting with reduced vocalizations
WHAT THE RESEARCH TELLS US
At 12 months, IT-HOME Learning Materials predicted child vocalizations. Infants with more stimulating toys and play materials vocalized more - the home environment was directly shaping their language development.
WHAT AN SLP SHOULD DO
Advocate for age-appropriate toys and books at home. Teach caregivers how to use these materials to encourage interaction - and support with models, prompts, and feedback so changes actually stick.
WHAT THIS MEANS FOR FUTURE RESEARCH
More research is needed across different home environments and across activities within the same environment. As this study showed, context matters - the same home can provide very different developmental opportunities depending on whether an infant is feeding, playing, or just awake and listening. Future studies should examine these distinctions more closely.
SECTION 7
Reflections
What this research taught me: This was my first experience conducting rigorous mixed methods research from study design through statistical analysis through publication. Running home visits, fitting infants with LENA vests, administering standardized assessments, and analyzing SPSS data - gave me a research foundation I carry into every project I do today.
What I'd do differently: The survey sample (Phase II) was distributed through online SLP forums which may have introduced self-selection bias - SLPs who actively engage in online professional communities may not represent all early intervention practitioners. A more diverse recruitment strategy would strengthen generalizability.
What this means for UX: The same question that drove this research drives my UX work - there's a gap between what people know and what they actually do. Understanding that gap, and designing interventions to close it, is at the core of both clinical research and product research.
SECTION 8
Publications
Peer reviewed publications
This work (my graduate thesis) contributed to two peer-reviewed, NIH-funded publications - both publicly available and searchable:
MIDWIFERY · VOLUME 116 · JANUARY 2023 · NIH FUNDED
The home environment and its relation to bottle feeding outcomes in the first year of life
Martens A, Carpenito T, Hines M, Iizuka A, Aspinwall B, Zimmerman E
PEDIATRIC MEDICINE · 2022 · NIH FUNDED
The home environment and its relation to vocalizations in the first year of life
Hines M, Carpenito T, Martens A, Iizuka A, Aspinwall B, Zimmerman E
conference presentations
ASHA NATIONAL CONFERENCE · 2019
American Speech-Language-Hearing Association
Presented findings on the relationship between the home environment, infant feeding, and vocalizations to a national audience of speech-language pathologists and researchers.
RISE SYMPOSIUM · 2019
Northeastern University Research Symposium
Presented a poster on longitudinal findings connecting IT-HOME subscales to infant feeding and vocalization outcomes at 3 and 12 months.