A normative study of the Color Trails Test in the adult Indian population.

The Color Trails Test (CTT) is a neuropsychological measure assessing for frontal and executive functioning, while also minimizing the cultural and language barriers inherent in similar measures such as the Trail Making Test (TMT). This study establishes convergent validity for the CTT in the Indian population by comparing participant performance on the CTT and TMT. It also generates culturally appropriate normative data for CTT-Form A among the Indian adult population. Six-hundred and sixty-nine cognitively healthy, community-dwelling individuals between ages 18 and 69 participated in the study and were stratified based on age, gender, and educational attainment. Participant performance on the CTT and TMT were correlated to establish convergent validity. Strong correlation was found between TMT-A and CTT-1 (r = 0.61) and between TMT-B and CTT-2 (r = 0.66). An analysis of variance test was used to determine the mean and standard deviation for each stratified participant group. Further analysis found that age and educational attainment significantly impact participant performance on CTT-1 [F(4, 649) = 4.395, p = 0.002], whereas gender, age, and educational attainment significantly impact participant performance on CTT-2 [F(4,649) = 2.446, p = 0.045]. Normative data generated from this study has important clinical implications and contributes to the growing body of culturally appropriate normative data available for the Indian population.

Right orbitofrontal cortex mediates conscious olfactory perception.

Understanding how the human brain translates sensory impressions into conscious percepts is a key challenge of neuroscience research. Work in this area has overwhelmingly centered on the conscious experience of vision at the exclusion of the other senses--in particular, smell. We hypothesized that the orbitofrontal cortex (OFC) is a central substrate for olfactory conscious experience because of its privileged physiological role in odor processing. Combining functional magnetic resonance imaging, peripheral autonomic recordings, and olfactory psychophysics, we studied a case of complete anosmia (smell loss) in a patient with circumscribed traumatic brain injury to the right OFC. Despite a complete absence of conscious olfaction, the patient exhibited robust "blind smell," as indexed by reliable odor-evoked neural activity in the left OFC and normal autonomic responses to odor hedonics during presentation of stimuli to the left nostril. These data highlight the right OFC's critical role in subserving human olfactory consciousness.

The mini-mental state examination in behavioral variant frontotemporal dementia and primary progressive aphasia.

There is little information regarding the usefulness of the Mini-Mental State Examination (MMSE) for tracking progression of non-Alzheimer's disease dementias. This study examined the utility of the MMSE in capturing disease severity in the behavioral variant frontotemporal dementia (bvFTD) and primary progressive aphasia (PPA), 2 nonamnestic clinical dementia syndromes. Retrospective data from 41 bvFTD and 30 PPA patients were analyzed. bvFTD patients' change in MMSE scores over time was significantly correlated with change over time on a measure of activities of daily living. In contrast, PPA patients' MMSE scores showed greater decline over time than scores on the activities of daily living scale. Results suggest that the MMSE score, heavily dependent on language skill, overestimates dementia severity in PPA patients. However, the score may be a more accurate measure of functional impairment in bvFTD due to the influence of their executive function and attentional deficits on MMSE performance.