Flavor Alterations Associated with Miracle Fruit and Gymnema sylvestre.

Taste and flavor (retronasal olfaction) interact in the brain. The rules of that interaction are not well understood. This study uses 2 taste modifiers that alter sweet to examine the effects on flavors. Subjects used the Global Sensory Intensity Scale to assess the aroma, sweetness, sourness, and flavor of 10 foods. As previous work had shown, miracle fruit added sweetness to acids, which secondarily reduced sourness (mixture suppression) and Gymnema sylvestre reduced sweetness in sweet foods as well as the sweetness induced by miracle fruit. In this study, multiple regression showed that both sweet and sour contribute to flavor. Gymnema sylvestre reduced the perceived sweet of predominantly sweet foods (chocolate and maple syrup) as expected; reducing the sweet, reduced the flavor. The effects of miracle fruit were complicated by its dual action: intensification of sweet and reduction of sour. Predominantly sour foods (vinegar, lemon, mustard, pickle) were sweetened by miracle fruit but any flavor enhancement associated with the added sweet appears to have been countered by the flavor reduction associated with reduced sourness. Moderately sour foods that are also sweet (tomatoes, strawberries) were sweetened by miracle fruit and thus flavor was enhanced; flavor loss through sour reduction was apparently not sufficient to counter the flavor enhancement due to increased sweet so the net result was that tomato and strawberry flavors were enhanced. The flavors of control foods (not predominantly sweet or sour [sausage, peanuts]) showed only small changes.

Impaired initial vowel versus consonant letter-word fluency in dementia of the Alzheimer type.

OBJECTIVES: Early detection of Alzheimer disease (AD) is important. With AD, the loss of connectivity should first induce dysfunction in those representational networks with the weakest connectivity. Less frequently used networks have weaker connectivity. Given the letter "A" has more phonemes than the letters "F" and "S", fewer words would begin with each of these "A" phonemes than with the "F" or "S" phonemes. We wanted to learn if patients with AD would produce fewer words starting with "A". METHODS: Patients with AD, mild cognitive impairment (MCI), and normal participants, were assessed with the Controlled Oral Word Association (COWA) test. RESULTS: Compared to controls and MCI patients, AD patients produced relatively fewer words beginning with "A" than with "F" and "S". CONCLUSIONS: These results support the postulate that the less frequently used, and thus more weakly connected, phonetic-lexical networks are more sensitive to the degradation induced by AD.

A brief olfactory test for Alzheimer's disease.

BACKGROUND: The early diagnosis of Alzheimer's disease (AD) may help reduce disability, enhance quality of life, and aid clinical trials. Portions of olfactory cortex are the initial sites of AD pathology and patients with AD often have more degeneration of their left than right hemisphere. Since the olfactory epithelium projects mainly to the ipsilateral olfactory cortex, patients with AD may demonstrate an asymmetrical (left greater than right) decrement of odor detection sensitivity. This retrospective, case-control study assessed a quick olfactory test that may help diagnose AD. METHODS: Participants with probable AD (N=18), mild cognitive impairment (MCI, N=24), other causes of dementia (OD, N=26) and matched controls (OC, N=26) were tested, with closed eyes, for their ability to detect an odor, one nostril at a time. A container of 14g of peanut butter was opened, held medially at the bottom of a 30cm ruler, and moved up 1cm at a time during the participants' exhale. Upon odor detection, the distance between the subject's nostril and container was measured. RESULTS: The mean odor detection distance of AD patients' left nostril (5.1cm), and not their right (17.4cm), was significantly less (F(3,90)=22.28, p<0.0001) than the other groups. The mean, standard error, and 95% Confidence Interval of the L-R nostril odor detection difference (cm) for AD were -12.4±0.5, (-15.0,-9.8); for MCI were -1.9±1.2, (-4.2,0.4); for OD were 4.8±1.0, (2.6,6.9); and for OC were 0.0±1.4 (-2.2,2.1). CONCLUSION: This non-invasive and inexpensive left-right nostril odor detection test appears to be a sensitive and specific test for probable AD.