Friday, April 06, 2007

Fast ForWord, Ga, mental time-keeping...some musings

Recently there has been some NASP listserv chatter regarding the Fast ForWord neurotechnology intervention program (click here) for kids with language or reading disabilities.

I've still not reviewed the intervention articles, but instead, have tried to find time to read some of the theoretical/empirical foundational literature that serves as the basis for the intervention. In the process I stumbled upon a nice overview of the conceptual/theoretical/research literature as articulated by one of the authors of this intervention program. The article was published (2003) in the prestigious (and one of my favorite) journals--Current Directions in Psychological Science.
  • Tallal, P. (2003). Language learning disabilities: Integrating research approaches. Current Directions in Psychological Science, 12 (6), 206-211 (click to view).
Below are a few select quotes from the article:
  • Why should the rate of auditory processing play such a critical role in normal as well as aberrant language development? One answer comes from an analysis of the acoustic properties of speech, which shows that the ability to track brief, rapidly successive frequency changes within the acoustic waveform of speech (known as formant transitions) is crucial for language development.
  • Benasich and I (Benasich Tallal, 2002) have hypothesized that individual differences in rapid-auditory-processing thresholds, which can be observed in infancy, affect what each brain binds together as nearly simultaneous, and this significantly affects the grain analysis that will be represented for speech. Substantial behavioral and physiological evidence shows that many individuals with early oral-language impairments are impaired in processing brief, rapidly successive acoustic cues within the tens of milliseconds needed for optimal phoneme representation. Similarly, many people with reading impairments (dyslexia) are characterized by deficits that reflect a difficulty segmenting words into sharply represented, discrete phonemes. This skill is critical for learning letter-sound associations. has been hypothesized that the high incidence of co-occurrence developmental oral- and writtenlanguage impairments is the result of common phonological deficits for a review, see Habib, 2000).
  • However, more recent research has challenged that perspective. Physiological studies have demonstrated that sensory neural maps can be significantly altered at the cellular level by intensive be-havioral training, even in adult animals. Of particular relevance to LLI are animal studies demonstrating that the capacity to segment rapidly successive auditory events can be sharpened by behavioral training based on Hebbian learning principles (Recanzone et al., 1993). On the basis of these studies, my colleagues and I (Merzenich et al., 1996; Tallal et al., 1996) hypothesized that it may be possible to improve the capacity of children with LLI to process the rapidly successive acoustic changes within ongoing speech. With the aid of computer technology, we developed a novel training approach (Fast For-Word®) disguised as a series of computer games. In a series of experiments, we studied the effectiveness of these games in improving the linguistic abilities of children with LLI. In one game, subjects indicate the temporal order of tones that are either rising or falling in pitch. The tones are designed to cover the range of frequencies and speeds that typify the acoustic frequency changes that occur in formant transitions in consonants. The computer program adaptively changes (increases or decreases) the duration of each tone and the rate at which one tone follows another based on each subject’s trial-by-trial performance, with the goal of increasing the ability to process more rapidly changing acoustic stimuli. In another approach, we use a computer algorithm to acoustically modify (amplify and temporally extend) the rapidly successive acoustic changes that occur within ongoing speech. This acoustically modified speech signal is used in a series of games to train language comprehension at all levels, from the phoneme to the whole sentence. As linguistic performance improves, the amount of acoustic modification adaptively decreases so that the stimuli become increasingly more like the stimuli that occur in normal speech.
  • These results support the hypothesis that basic acoustic frequency and temporal (spectrotemporal) processing constraints play a significant role in LLI. Furthermore, they demonstrate that training using acoustically modified speech can ameliorate these processing constraints, as well as the effect they have on speech and language processing. Habib et al. (2002) obtained similar results in an independent study with French children with dyslexia.
I haven't had time to think this all through, but the focus on rapid temporal processing seems to have some parallels to the theoretical and intervention research related to my interest in the IQ Brain Clock--that is, mental or interval time-keeping. I sense some connections....I need to let things percolate in my cortex for a while. Comments by those who can make these connections quicker are appreciated.

Also, this research suggests that there are likely some yet specified narrow Ga (auditory processing) abilities that need to be investigated for possible inclusion in the CHC theory of cognitive abilities.

So many interesting articles to little time

PS - I just recalled a related post at IQ's Corner re: rapid auditory gap detection.

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