Epidemiological studies suggested that elevated plasma homocysteine (Hcy) is associated with an increased risk of depression and cerebrovascular disease (CVD). There were few published reports of Hcy levels and methylenetetrahydrofolate reductase (MTHFR) C677T genotype in geriatric depression.

To investigate the relationship among plasma Hcy level, MTHFR C677T polymorphism and geriatric depression in the Chinese population.

The plasma Hcy level measured by capillary electrophoresis with ultraviolet detection and the C667T polymorphism of MTHFR detected using polymerase chain reaction-restriction fragment length polymorphism assay were determined in 116 patients with geriatric depression and in 80 healthy controls.

The plasma Hcy level in the patients with geriatric depression was significantly higher than that in controls (p < 0.001). The age of first episode and comorbid CVD were significantly correlated with plasma Hcy levels in geriatric patients (p = 0.014 and 0.008, respectively). The Hamilton Rating Scale for Depression total score and plasma Hcy level at baseline showed no significant correlation in the patients (r = −0.111, p = 0.397). There were no significant differences in the MTHFR C677T polymorphism genotypes and alleles between the patients and the healthy controls (p = 0.654 and 0.573, respectively).

The elevated plasma Hcy level is a risk factor for geriatric depression. MTHFR C667T genotype is not associated with geriatric depression in the Chinese population.

Constitute hypothesis for origin of supernumerary phantom limb (SPL) after stroke.

Single case description, review of literature and formulation of hypothesis.

A 59-year-old lady was evaluated for complaints of left-sided hemiparesis and extra limbs attached to her left shoulder for the past 7 months. Neuropsychological assessment revealed left hemineglect with SPL, and profile suggested bilateral frontal, right parietotemporal and basal ganglia involvement. Magnetic resonance imaging brain scan showed gliotic cavity secondary to the old haematoma in right putamen with white matter changes in the right frontoparietotemporal lobes.

The conceptual framework of body schema can be used to classify many of the neurological disorders of body representation. Generation of SPL comes under the subtype of pathology of updating among the disorders of body schema. The continuous updating allows the body schema to modulate perceptual processing of objects according to their position in space. Brain areas classified as parts of motor system can, under pathological conditions (haemorrhage), influence body perception. So, when she used to move her arm, the representation of the estimated position was not updated by the motor commands. Sensory and motor information therefore becomes discrepant, and failure to integrate these two sources of information leads to loss of normal coherence, and the perceived shape of the body was altered by adding a SPL to accommodate the discrepancy.

A prevailing belief is that opioids tend not to impair cognitive performance in opioid-dependent users. However, the impact of heroin abuse on verbal memory, especially on working memory, is not well studied and the results available are inconsistent.

This study was carried out to test the hypothesis that abstinent heroin abusers have intact working memory capacity.

N-back task and backward digit span task were used to measure the verbal working memory capacity in 28 abstinent heroin abusers and 25 controls matched for age, education level and gender. Forward digit span task was used as a control task to measure short-term memory capacity.

Compared with the control subjects, heroin abusers showed normal backward/forward digit spans but significant performance impairment in the n-back task.

Abstinent heroin abusers have intact short-term memory capacity but impaired verbal working memory capacity.