Objective To investigate emotion discrimination abilities in healthy comparison subjects, patients with mild cognitive impairment (MCI), early and moderate Alzheimer disease (AD). Design Prospective study design. Setting Outpatient memory clinic, Department of Psychiatry, Innsbruck, Austria. Methods One hundred forty-one subjects older than 60 years were included in the study. Thirty-five subjects were classified as healthy comparison subjects, 51 subjects as MCI (21 subjects with amnestic MCI single domain, 31 subjects with amnestic MCI multiple domain), 32 subjects with early AD and 23 subjects with moderate AD. Measurements All subjects were tested on an extensive neuropsychological test battery including the Penn Emotion Recognition Tests and depression symptoms were assessed additionally. Results Healthy subjects and patients with MCI, early and moderate AD differed significantly in the recognition of all emotions and neutral faces combined. When separated by emotion, the authors found significant differences in emotion recognition between the diagnostic groups for happy, sad, fearful, and neutral faces. Compared with comparison subjects, amnestic MCI patients single domain did not differ significantly in their emotion recognition abilities, but amnestic MCI multiple domain patients were already impaired in the recognition of overall emotions, sad, fearful, and neutral faces and the deficits increased with the severity of AD. Depression had a significant influence on the recognition of overall emotion and neutral faces and increased the probability of misinterpreting neutral faces as sad leading to a negative bias. Conclusions Diminished abilities for emotion discrimination are already present in patients with MCI and further decreased with AD progression.

The catechol-O-methyltransferase (COMT) Val158Met polymorphism modulates executive functions and working memory and recent neuroimaging studies implicate an association with emotional processing. We examined the relationship between the COMT Val158Met polymorphism and facial emotion recognition and differentiation in 100 healthy individuals. Compared to Met homozygosity, Val homozygosity was associated with better and faster recognition of negative facial expressions such as anger and sad. Our study provides evidence for a possible influence of the COMT polymorphism on emotion recognition abilities in healthy subjects. Additional research is needed to further define the neurocognitive phenotypes associated with COMT polymorphisms.

The applicability of ion-pair reversed-phase high-performance liquid chromatography hyphenated to electrospray ionization time-of-flight mass spectrometry (ICEMS) for the haplotyping of five SNPs (rs769223, rs4818, rs4986871, rs8192488, rs4680) located within exon 4 of the human catechol-O-methyltransferase (COMT, EC 2.1.1.6) gene is demonstrated. Two differently sized products of polymerase chain reaction--a 71-bp amplicon partially covering the sequence of a 124-bp amplicon--were used to determine unequivocally the allelic states of the single nucleotide polymorphisms linked on both chromosomes. The two amplicons were co-loaded onto the chromatographic column and simultaneously analyzed within a single gradient run. Using the described strategy, 101 individuals representing an Austrian population sample were typed. The obtained haplotype frequencies will serve as reference values in future association studies to examine the impact of the COMT gene on neuropsychiatric disorders. Additionally, two newly discovered polymorphic sites within the sequence of the COMT gene are described (a synonymous C>T mutation at the third position of the amino acid codon 99 in the soluble COMT protein or 149 in the membrane-bound COMT protein; a non-synonymous G>A substitution at the second position of the amino acid codon 95 in the soluble COMT protein or 145 in the membrane-bound-COMT protein).