A study of neurobehavioral, clinical psychometric, and P3 changes in vitamin B12 deficiency neurological syndrome.

OBJECTIVE

To evaluate cognitive functions and behavioral changes in the patients with vitamin B12 deficiency neurological syndromes (VBDNS) using detailed clinical psychometric and P3 studies and their response to treatment.

METHODS

The patients with VBDNS were included and their detailed medical history was recorded. Neurobehavioral and cognitive functions were evaluated by neuropsychiatry inventory (NPI), forward and backward digit span, mini mental state examination (MMSE), Luria's three-step test, trail making test (TMT), motor speed and precision test (MSPT), Benton's visual retention test (BVRT), clock drawing (CD), category fluency, hospital anxiety and depression (HAD) scale, and cognitive evoked potential using oddball paradigm at baseline and 3 and 6 months following treatment. Complete hemogram, serum chemistry, vitamin B12, homocysteine, and craniospinal magnetic resonance imaging (MRI) were done.

RESULTS

Thirty-three patients with VBDNS, whose median age was 43 (12-68) years, five (15.2%) of whom were females were included. Twenty-one patients had neurobehavioral/cognitive decline, 26 myelopathy, and 17 neuropathy. MSPT, TMT, CD, and HAD scores improved significantly at 3 months and category naming and MMSE improved at 6 months compared to baseline. The P3 latency also improved significantly at 3 months. The baseline P3 changes correlated with MMSE, Luria's three-step test, and MSPT. Hemoglobin and mean corpuscular volume also correlated with some of the cognitive tests.

CONCLUSION

VBDNS results in frontal-subcortical neurobehavioral and cognitive abnormalities which may be due to cortical and subcortical dysfunction. The reversibility of these changes is suggestive of metabolic alteration in neuronal or myelin function.