Baby talk helps babies’ brains process speech in their first year of life

Marina Kalashnikova – m.kalashnikova@bcbl.eu.au
Basque Center on Cognition, Brain and Language
Paseo Mikeletegi 69,
San Sebastian, Spain, 20009

Popular version of paper 2aSCa
Presented Tuesday morning, May 14, 2019
177th ASA Meeting, Louisville, KY

When adults interact with young babies, they use a special type of speech that is slow, melodic, warm, and happy. This speech type or register is known as baby talk or infant-directed speech. Babies like infant-directed speech, and they usually reward adults for using it by paying attention, smiling, and vocalising in response. Thus, the use of infant-directed speech allows parents to convey warm and positive emotions to their babies to make them feel safe, comfort and soothe them. Our research demonstrates that the benefits of infant-directed speech go even further, and that in fact, it may be a powerful tool that adults have at their disposal to assist their young babies in the process of learning language.

When infants come to this world, they have the general capacity to learn any language, but in their first year of life, they must use the speech input from their environment to fine-tune this ability and become language-specific listeners and learners. Any adult who has ever heard someone speaking a foreign language can imagine how difficult this task is since unfamiliar speech usually sounds like one continuous string with no clues about where individual words start and end, and what sounds are used to make up words. This is similar to infants’ first experiences with language, but they have access to infant-directed speech, which assists them in two ways. First, its attention-grabbing properties help infants focus on the speech directed to them over all the other speech and non-speech sounds that they hear in their surroundings. Second, infant-directed speech is characterised by exaggerated speech sounds (i.e., clearer distinctions between different vowel sounds like ee, oo, and ah), which are easier for infants to perceive, discriminate, learn, and later reproduce.

This evidence comes from a series of experiments in which we recorded brain activity in infants from 4 to 9 months of age when they listened to speech passages or to isolated vowel sounds produced in infant-directed or in adult-directed speech. Our results showed that when infants heard infant-directed speech, their brain responses were more mature and similar to the responses of adult brains in response to speech. This indicates that the early encoding of infant-directed speech is less effortful and more efficient.

This efficiency in encoding the speech signal leads to better segmentation of speech into meaningful units, formation of speech sound categories, and comprehension of speech. Thus adults, perhaps unconsciously, provide their young babies with just the type of speech input that they need to succeed in the challenging tasks of learning language.

Photoacoustic imaging in cancer medicine and research: systems, results and future directions

Prof. Jeff Bamber, jeffrey.bamber@virginmedia.com
Institute of Cancer Research and Royal Marsden Hospital
Sutton, London, UK

Popular version of paper 3aBA1
Presented Wednesday morning, May 15, 2019
177th ASA Meeting, Louisville, KY

Photoacoustic imaging is an exciting and relatively new way to externally scan the body, to make images of internal organs, tissues and disease. It uses both sound and light, combining the two forms of energy to take advantage of the best features of both. To make this method work, the body surface is illuminated with short pulses of light. Wherever the light is absorbed, which may be at depths of many centimetres inside the body, it causes a small and brief increase in temperature. This creates a pressure disturbance that travels back to the body surface as a sound wave which can be detected by a medical ultrasound scanner and be used to make an image. It brings to medical ultrasound the ability to show optical colour and thus some of the molecules that tissues contain, or an injected “dye” or nanoparticles. This can be useful in showing how much blood there is in tumours, whether the blood is well-oxygenated, what the vascular pattern looks like, the relative concentrations of melanin, fat and water, and the concentrations and distribution of nanoparticles and anticancer drugs. Potential uses of such information span all aspects of cancer medicine, including cancer detection, diagnosis, prognosis, treatment guidance, prediction of response to treatment and monitoring of response to treatment.

This paper reviews selected previous work in photoacoustic imaging conducted at the Institute of Cancer Research or with our collaborators, and considers directions for future research. In summary, for flexible introduction as an additional type of ultrasound scanning, we built a clinical photoacoustic system by adapting a commercial ultrasound scanner. Early clinical experience using this to scan breast tumours provided images that showed similar features of the tumours as those seen in contrast magnetic resonance images but also showed that photoacoustic image quality is limited by false detail created by sound waves emitted when light is absorbed at the skin surface, which can be reflected back to the surface from deeper tissues. Ideas for reducing the impact of this false detail, which we call clutter, were therefore explored. These ideas have included computer recognition of features of the clutter so that it can be suppressed in the images, the use of injected materials called contrast agents which increase the desired signal so that the clutter is relatively less important, and deliberately moving or vibrating the tissue, which allows clutter to be distinguished from real detail because the two types of detail move in a predictably different way. The last of these approaches was particularly successful, with a technique known as localised vibration tagging (LOVIT). For example, it tripled penetration depth in breast-mimicking phantoms. Most of the clutter reduction methods are complementary in nature, and a combined approach therefore represents a worthwhile direction for the future work.