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Biomedical subjects

Minna Huotilainen

Publications and source records attributed to Minna Huotilainen.

At least 19 recordsLinked to original sources
PubMed2006

Neonatal frequency discrimination in 250-4000-Hz range: electrophysiological evidence.

OBJECTIVE: The precision of sound frequency discrimination in newborn infants in the 250-4000-Hz frequency range was determined using the neonatal electrophysiological mismatch response (MMR), the infant equivalent of adult mismatch negativity (MMN). METHODS: The electroencephalogram (EEG) was recorded in 11 full-term sleeping newborn infants mostly in active sleep (67% of the time). Pure tones were presented through loudspeakers in an oddball paradigm with a 800-ms stimulus onset asynchrony (SOA). Each stimulus block contained a standard (p=0.76) of 250, 1000, or 4000Hz in frequency (in separate blocks) and deviants with a frequency change of either 5% or 20% of the standard (p=0.12 of each). RESULTS: A positive ERP deflection was found at 200-300ms from stimulus onset in response to the 20% deviation from the 250, 1000, and 4000Hz standard frequencies. The amplitude of the response in the 200-300ms time window was significantly larger for the 20% than 5% deviation. CONCLUSIONS: We observed in newborn infants automatic frequency discrimination as reflected by a positive MMR. The newborns were able to discriminate frequency change of 20% in the 250-4000-Hz frequency range, whereas the discrimination of the 5% frequency change was not statistically confirmed. SIGNIFICANCE: The present data hence suggest that the neonatal frequency discrimination has lower resolution than that in adult and older children data.

Acoustic Stimulation↗
PubMed2006

Measurement of extensive auditory discrimination profiles using the mismatch negativity (MMN) of the auditory event-related potential (ERP).

OBJECTIVE: Mismatch negativity (MMN), a change-specific component of the auditory event-related potential (ERP), is sensitive to deficits in central auditory processing associated with many clinical conditions. The aim of this study was to obtain a comprehensive multi-dimensional profile of central auditory processing by extending the recently developed fast multi-feature MMN paradigm [Näätänen R, Pakarinen S, Rinne T, Takegata R. The mismatch negativity (MMN): towards the optimal paradigm. Clin Neurophysiol 2004;115:140-144]. METHODS: MMN responses to changes in sound duration, frequency, intensity, and perceived sound-source location at six different magnitudes of deviation were recorded from healthy young adults by using the multi-feature MMN paradigm. In addition, behavioural discrimination accuracy and speed were measured to examine the relationship between MMN and behavioural performance. RESULTS: All the 24 sound changes elicited significant MMNs. MMN amplitude increased and latency decreased with increasing magnitude of sound change. Furthermore, the MMN amplitude and latency predicted the subjects' accuracy and speed in detecting these deviations. CONCLUSIONS: This new paradigm provides an extensive auditory discrimination profile for several auditory attributes at different deviation magnitudes in a minimal recording time. SIGNIFICANCE: The auditory discrimination profiles can offer a comprehensive view of the development, plasticity, and deficits of central auditory processing.

Acoustic Stimulation↗
PubMed2006

Magnetoencephalography of the newborn brain.

This paper reviews the use of event-related magnetic fields (ERFs) in infants; ERFs can be derived from magnetoencephalography by means of averaging. Basic perceptive skills are important prerequisites for the infant's later development. The automatic cortical processes related to processing auditory, somatosensory and visual stimuli can be addressed by using responses recorded directly from the brain. The traditional method, the event-related potential (ERP), has recently been accompanied by ERFs. Similarly to ERPs, higher processes related to short-term memory, stimulus comparisons, and attention allocation can also be studied with ERFs. Further, since addressing the neonatal higher cognitive and social capabilities is challenging using only behavioural means, ERFs provide information on these important functions at a very early stage immediately after birth or in some cases even before birth. The main advantage of ERFs, compared to ERPs, is detection of the signals with high accuracy both with respect to the noise level and estimation of the spatial location.

Arousal↗
PubMed2006

Cortical auditory event-related potentials in newborn infants.

The possibility of recording changes in electroencephalography potentials following perception of sound was reported several decades ago. The recent expanding research on auditory cortical event-related potentials (AERPs) for assessing sound discrimination abilities in children and infants has indicated that several methodological issues need to be addressed before it can be implemented in clinical practice. Latencies, polarities, and amplitudes of the responses change with gestational age and during infancy. Thus, the maturation of the infant must be considered when designing stimulus paradigms and interpreting the responses. Of healthy newborn infants, only about 80% will show mismatch negativity, the automatic change detection of the auditory stimuli. Currently, the AERP method cannot be applied in clinical practice in the neonatal period, although the findings in healthy newborns at risk for dyslexia are promising. Further research will elucidate the possibility of developing AERPs as a possible early screening method during infancy for later dyslexia or cognitive dysfunction.

Dyslexia↗
PubMed2006

Training in Morse code enhances involuntary attentional switching to acoustic frequency: Evidence from ERPs.

This study examined the possibility that learning Morse code could result in cortical changes in processing of physical acoustic features, as indexed by the mismatch negativity (MMN) and P3a components of the auditory event-related potential (ERP). ERPs were recorded in 9 subjects who were learning Morse code. The subjects were presented with auditory stimuli at 3 different times relative to their training (before, during and after). These stimuli were presented within an auditory 'oddball' paradigm, with repetitive standard stimuli interspersed by one of three infrequent deviant stimuli (duration, frequency or SOA). The data showed that there was a significant increase in the P3a only for frequency deviants as a function of training, whereas the MMN response was not affected by the training. These data are interpreted in terms of an attentional switching to unfamiliar changes that participants would not expect among the signals that they would grow to anticipate while receiving Morse code.

Acoustic Stimulation↗
PubMed2006

Mismatch negativity (MMN) elicited by changes in phoneme length: a cross-linguistic study.

Speech sounds representing different phonetic categories are typically easier to discriminate than sounds belonging to the same category. This phenomenon is referred to as the phoneme boundary effect. We aimed to determine whether, at neural level, this effect is indeed due to crossing the phoneme boundary. The mismatch negativity (MMN) brain response was measured for across- and within-category changes in Finnish phoneme length in native speakers and second-language users of Finnish as well as non-Finnish-speaking subjects. The results showed that the MMN amplitude was enhanced in the native speakers in comparison with the two non-native groups which, in turn, did not differ from each other in MMN amplitude. The response pattern to across- and within-category changes, however, was the same in all groups regardless of whether or not they had the phoneme categories. Thus, the responses could not be determined by crossing the phoneme boundary. Rather, the enhancement of MMN amplitude in the native speakers is likely to be due to the activation of native-language phonetic prototypes. The second-language users, however, did not seem to have automatic access to Finnish prototypes.

Analysis of Variance↗
PubMed2006

Newborns discriminate novel from harmonic sounds: a study using magnetoencephalography.

OBJECTIVE: We investigated whether newborns respond differently to novel and deviant sounds during quiet sleep. METHODS: Twelve healthy neonates were presented with a three-stimulus oddball paradigm, consisting of frequent standard (76%), infrequent deviant (12%), and infrequent novel stimuli (12%). The standards and deviants were counterbalanced between the newborns and consisted of 500 and 750 Hz tones with two upper harmonics. The novel stimuli contained animal, human, and mechanical sounds. All stimuli had a duration of 300 ms and the stimulus onset asynchrony was 1s. Evoked magnetic responses during quiet sleep were recorded and averaged offline. RESULTS: Two deflections peaking at 345 and 615 ms after stimulus onset were observed in the evoked responses of most of the newborns. The first deflection was larger to novel and deviant stimuli than to the standard and, furthermore, larger to novel than to deviant stimuli. The second deflection was larger to novel and deviant stimuli than to standards, but did not differ between the novels and deviants. CONCLUSIONS: The two deflections found in the present study reflect different mechanisms of auditory change detection and discriminative processes. SIGNIFICANCE: The early brain indicators of novelty detection may be crucial in assessing the normal and abnormal cortical function in newborns. Further, studying evoked magnetic fields to complex auditory stimulation in healthy newborns is needed for studying the newborns at-risk for cognitive or language problems.

Acoustic Stimulation↗
PubMed2005

The discrimination of and orienting to speech and non-speech sounds in children with autism.

The present study aimed to find out how different stages of cortical auditory processing (sound encoding, discrimination, and orienting) are affected in children with autism. To this end, auditory event-related potentials (ERP) were studied in 15 children with autism and their controls. Their responses were recorded for pitch, duration, and vowel changes in speech stimuli, and for corresponding changes in the non-speech counterparts of the stimuli, while the children watched silent videos and ignored the stimuli. The responses to sound repetition were diminished in amplitude in the children with autism, reflecting impaired sound encoding. The mismatch negativity (MMN), an ERP indexing sound discrimination, was enhanced in the children with autism as far as pitch changes were concerned. This is consistent with earlier studies reporting auditory hypersensitivity and good pitch-processing abilities, as well as with theories proposing enhanced perception of local stimulus features in individuals with autism. The discrimination of duration changes was impaired in these children, however. Finally, involuntary orienting to sound changes, as reflected by the P3a ERP, was more impaired for speech than non-speech sounds in the children with autism, suggesting deficits particularly in social orienting. This has been proposed to be one of the earliest symptoms to emerge, with pervasive effects on later development.

Acoustic Stimulation↗
PubMed2005

Phoneme quality and quantity are processed independently in the human brain.

In speech perception, the primary cue of phoneme recognition is typically the spectral quality of the speech sound. In some languages, however, even speech-sound duration may serve as a phonological cue. This distinction is called quantity. We used a component of event-related potential, the mismatch negativity, to determine whether phoneme quality and quantity are processed independently in the human brain. We found that the mismatch negativity responses to phoneme quality and quantity changes are additive, indicating that the analysis of these features is independent of each other. This suggests that phoneme quality and quantity are processed by separate neural processes that, in a system model, may be regarded as different levels in the phonological system.

Acoustic Stimulation↗
PubMed2005

Does sleep quality affect involuntary attention switching system?

We studied the relationship between sleep quality and quantity and subsequently recorded automatically evoked event-related potential (ERP) responses. In previous studies decrement of attentional processing has been associated with changes in sleep. Sleep is shown to associate also with ERPs elicited by unattended sound stream, however, there is no consensus on these effects. A recent study suggested that the early anterior P3a to novel stimuli in attended stream is attenuated and the late parietal P3a is strengthened by total sleep deprivation. We carried out 72-h consecutive actigraphy measurements in a naturalistic setting to collect information about variation in sleep duration, sleep onset latency, sleep efficiency, and percentage of sleep. MMN and P3a deflections to infrequent changes in sound duration and pitch in unattended sound stream were obtained in a separate recording session from the same subjects when they were awake. No significant correlations were found between sleep and MMN parameters, indicating that MMN is resistant to normal variation in sleep. However, P3a to both pitch and duration changes correlated positively with sleep onset latency, and P3a to duration changes correlated negatively with sleep efficiency and percentage of sleep. The correlation was higher in the posterior scalp areas. Our results suggest that the involuntary attention switching system, reflected by the P3a is sensitized as a function of decreased sleep quality.

Acoustic Stimulation↗
PubMed2005

Bilateral hemodynamic responses to auditory stimulation in newborn infants.

We studied hemodynamic auditory evoked responses of 20 healthy full-term neonates with near-infrared spectroscopy. The instrument used allows the measurements to be performed simultaneously above both auditory cortices. The stimulation consisted of 5-s trains of sound (700-ms interstimulus interval) with a 25-s silent interval. In response to the stimulation, a significant increase in concentration of oxygenated hemoglobin was detected in 14 out of 21 measurements. The mean latency of the largest response was 9.63+/-2.20 s (mean+/-SD) and the mean amplitude was 1.02+/-0.53 microM. The response amplitude was significantly larger in active (1.28+/-0.59 microM) than in quiet sleep (0.76+/-0.32 microM). The latency of the oxygenated hemoglobin concentration response was significantly shorter (r=-0.70 and p=0.0023) for infants with higher gestational age.

Acoustic Stimulation↗
PubMed2005

Sound frequency change detection in fetuses and newborns, a magnetoencephalographic study.

The mismatch negativity (MMN) response to auditory stimuli has been successfully recorded in newborns thus demonstrating the discriminative cognitive ability. The aim of our study was to determine whether and when such an MMN response could be detected in the human fetus. The recordings of weak magnetic fields from the fetal brain were performed with the 151 channel MEG system called SARA (SQUID Array for Reproductive Assessment). Two tone bursts were presented in a sequence of a standard complex tone of 500 Hz intermixed with a deviant complex tone of 750 Hz in 12% of the stimuli. Sound intensity delivered over the maternal abdomen was 110 dB. The interstimulus interval (ISI) varied between 500 ms and 1100 ms. Fetal response, corresponding to sound frequency change detection, was calculated from the records where responses to standard and deviant tones were observed. A successful response was found in 60% of 25 fetal recordings. The MMN response with an average latency of 321 ms was observed in 48% of the fetal data. In 12% of the fetal data, a late component, referred to as the late discriminative negativity (LDN) response, was detected with an average latency of 458 ms. The same paradigm was applied in 5 newborns after birth. The capability for sound discrimination is a prerequisite for normal speech development. The investigation of sound discrimination and related cortical activity of the fetus can help to identify and determine the nature of deficits caused by central processes in the auditory system at very early stages.

Acoustic Stimulation↗
PubMed2005

The role of blind humans' visual cortex in auditory change detection.

Several studies using brain imaging have demonstrated occipital-cortex activation in blind individuals during tactile and auditory tasks, suggesting that the visual cortex deprived of its normal input has adopted a new role in information processing. So far, however, at what stages of information processing and to which perceptual sub-processes this applies remains unclear. We determined the auditory functions of this cortical region in early-blind humans by means of functional magnetic resonance imaging. We found that these areas were not activated by the mere presence of sound, but were involved in the attentive processing of changes in the auditory environment, which is important in detecting potentially dangerous or other important events in the surroundings, for example.

Acoustic Stimulation↗
PubMed2005

Short-term memory functions of the human fetus recorded with magnetoencephalography.

Studies in fetuses and in prematurely born infants show that auditory discriminative skills are present prior to birth. The magnetic fields generated by the fetal brain activity pass the maternal tissues and, despite their weakness, can be detected externally using MEG. Recent studies on the auditory evoked magnetic responses show that the fetal brain responds to sound onset. In contrast, higher-level auditory skills, such as those involving discriminative and memory functions, were not so far studied in fetuses with MEG. Here we show that fetal responses related to discriminating sounds can be recorded, implicating that the auditory change-detection system is functional. These results open new views to developmental neuroscience by enabling one to determine the sensory capabilities as well as the extent and accuracy of the short-term memory system of the fetus, and, further, to follow the development of these crucial processes.

Adult↗
PubMed2005

Speech-sound duration processing in a second language is specific to phonetic categories.

The mismatch negativity (MMN) component of the auditory event-related potential was used to determine the effect of native language, Russian, on the processing of speech-sound duration in a second language, Finnish, that uses duration as a cue for phonological distinction. The native-language effect was compared with Finnish vowels that either can or cannot be categorized using the Russian phonological system. The results showed that the duration-change MMN for the Finnish sounds that could be categorized through Russian was reduced in comparison with that for the Finnish sounds having no Russian equivalent. In the Finnish sounds that can be mapped through the Russian phonological system, the facilitation of the duration processing may be inhibited by the native Russian language. However, for the sounds that have no Russian equivalent, new vowel categories independent of the native Russian language have apparently been established, enabling a native-like duration processing of Finnish.

Child↗
PubMed2005

A kind of auditory 'primitive intelligence' already present at birth.

'Primitive intelligence' in audition refers to the capacity of the auditory system to adaptatively model the acoustic regularity and react neurophysiologically to violations of such regularity, thus supporting the ability to predict future auditory events. In the present study, event-related brain potentials to pairs of tones were recorded in 11 human newborns to determine the infants' ability to extract an abstract acoustic rule, the direction of a frequency change. Most of the pairs (standard, P = 0.875) were of ascending frequency (i.e. the second tone higher than the first), while the remaining pairs (deviant, P = 0.125) were of descending frequency (the second tone being lower). Their frequencies varied among seven levels to prevent discrimination between standard and deviant pairs on the basis of absolute frequencies. We found that event-related brain potentials to deviant pairs differed in amplitude from those to standard pairs at 50-450 ms from the onset of the second tone of a pair, indicating the infants' ability to represent the abstract rule. This finding suggests the early ontogenetic origin of 'primitive intelligence' in audition that eventually may form a prerequisite for later language acquisition.

Acoustic Stimulation↗
PubMed2005

The perception of phonological quantity based on durational cues by native speakers, second-language users and nonspeakers of Finnish.

Some languages, such as Finnish, use speech-sound duration as the primary cue for a phonological quantity distinction. For second-language (L2) learners, quantity is often difficult to master if speech-sound duration plays a less important role in the phonology of their native language (L1). By comparing the categorization performance of native speakers of Finnish, Russian L2 users of Finnish, and non-Finnish-speaking Russians, the present study aimed to determine whether the L2 users, whose native language does not have a quantity distinction, have been able to establish categories for Finnish quantity. The results suggest that the native speakers and some of the L2 users that have been exposed to Finnish for a longer time have access to phonological quantity categories, whereas the L2 users with shorter exposure and the non-Finnish-speaking subjects do not. In addition, by comparing categorization and discrimination tasks it was found that the native speakers show a phoneme-boundary effect for quantity that is cued by duration only, whereas the non-Finnish-speaking subjects and the subjects with low proficiency in Finnish do not.

Adolescent↗