Vagus nerve stimulation in patients with Alzheimer's disease: Additional follow-up results of a pilot study through 1 year.
BACKGROUND
Cognitive-enhancing effects of vagus nerve stimulation (VNS) have been reported during 6 months of treatment in a pilot study of patients with Alzheimer's disease (AD). Data through 1 year of VNS (collected from June 2000 to September 2003) are now reported.


METHODS
All patients (N = 17) met the National Institute of Neurological and Communicative Disorders and Stroke and the Alzheimer's Disease and Related Disorders Association (NINCDS-ADRDA) criteria for probable AD. Responder rates for the Alzheimer's Disease Assessment Scale-cognitive subscale (ADAS-cog) and Mini-Mental State Examination (MMSE) were measured as improvement or absence of decline from baseline. Global change, depressive symptoms, and quality of life were also assessed. Cerebrospinal fluid (CSF) levels for total tau, tau phosphorylated at Thr181 (phosphotau), and Abeta42 were measured by standardized enzyme-linked immunosorbent assay (ELISA).


RESULTS
VNS was well tolerated. After 1 year, 7 (41.2%) of 17 patients and 12 (70.6%) of 17 patients improved or did not decline from baseline on the ADAS-cog and MMSE, respectively. Twelve of 17 patients were rated as having no change or some improvement from baseline on the Clinician Interview-Based Impression of Change (CIBIC+). No significant decline in mood, behavior, or quality of life occurred during 1 year of treatment. The median change in CSF tau at 1 year was a reduction of 4.8% (p = .057), with a 5.0% increase in phosphotau (p = .040; N = 14).


CONCLUSIONS
The results of this study support long-term tolerability of VNS among patients with AD and warrant further investigation.
Merrill
Charley A
CA
Forest Research Institute, Jersey City, NJ, USA.
Jonsson
Michael A G
MA
Minthon
Lennart
L
Ejnell
Hasse
H
C-son Silander
Hans
H
Blennow
Kaj
K
Karlsson
Mats
M
Nordlund
Arto
A
Rolstad
Sindre
S
Warkentin
Siegbert
S
Ben-Menachem
Elinor
E
Sjögren
Magnus J C
MJ
D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000134:cerebrospinal fluid / Q000175:diagnosis / Q000628:therapy*; D016229:Amyloid beta-Peptides / Q000134:cerebrospinal fluid; D015415:Biomarkers / Q000134:cerebrospinal fluid; D002800:Cholinesterase Inhibitors / Q000627:therapeutic use; D003072:Cognition Disorders / Q000134:cerebrospinal fluid / Q000175:diagnosis / Q000628:therapy*; D003131:Combined Modality Therapy; D003863:Depression / Q000134:cerebrospinal fluid / Q000175:diagnosis / Q000523:psychology; D004599:Electric Stimulation Therapy / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008565:Membrane Proteins / Q000134:cerebrospinal fluid; D008875:Middle Aged; D010865:Pilot Projects; D011569:Psychiatric Status Rating Scales / Q000706:statistics & numerical data; D011788:Quality of Life; D013654:Taurine / Q000031:analogs & derivatives / Q000134:cerebrospinal fluid; D016896:Treatment Outcome; D014630:Vagus Nerve / Q000502:physiology*; D016875:tau Proteins
D016229:Amyloid beta-Peptides; D015415:Biomarkers; D002800:Cholinesterase Inhibitors; D008565:Membrane Proteins; D013654:Taurine; C016127:taurocyaminphosphate; C054369:MAPT protein, human; D016875:tau Proteins