Low-Frequency Repetitive Transcranial Magnetic Stimulation of the Right Dorsolateral Prefrontal Cortex Enhances Recognition Memory in Alzheimer’s Disease
Affiliations: [a] Department of Psychology, Educational Sciences and Human Movement, University of Palermo, Palermo, Italy
| [b] NeuroTeam Life and Science, Palermo, Italy
| [c] Unità di Neurologia Cognitiva e Riabilitazione, ARNAS Garibaldi, Catania, Italy
| [d] NEUROFARBA Department, University of Firenze, Firenze, Italy
| [e] Department of Neuropsychology, National Hospital for Neurology and Neurosurgery, London, UK
Correspondence:
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Correspondence to: Patrizia Turriziani, PhD, Department of Psychology, Educational Science and Human Movement, University of Palermo, Viale delle Scienze, Ed. 15, 90128 Palermo, Italy. Tel.: +39 09123897750; Fax: +39 0917028429; E-mail: patrizia.turriziani@unipa.it.
Abstract: Background:The lack of effective pharmacological or behavioral interventions for memory impairments associated with Alzheimer’s disease (AD) emphasizes the need for the investigation of approaches based on neuromodulation. Objective:This study examined the effects of inhibitory repetitive transcranial magnetic stimulation (rTMS) of prefrontal cortex on recognition memory in AD patients. Methods:In a first experiment, 24 mild AD patients received sham and real 1Hz rTMS over the left and right dorsolateral prefrontal cortex (DLPFC), in different sessions, between encoding and retrieval phases of a non-verbal recognition memory task. In a second experiment, another group of 14 AD patients underwent sham controlled repeated sessions of 1Hz rTMS of the right DLPFC across a two week treatment. Non-verbal recognition memory task was performed at baseline, at the end of the two weeks period and at a follow up of 1 month. Results:Right real rTMS significantly improved memory performance compared to right sham rTMS (p = 0.001). Left real rTMS left the memory performance unchanged as compared with left sham rTMS (p = 0.46). The two sham conditions did not differ between each other (p = 0.24). In the second experiment, AD patients treated with real rTMS showed an improvement of memory performance at the end of the two weeks treatment (p = 0.0009), that persisted at 1-month follow-up (p = 0.002). Conclusion:These findings provide evidence that inhibitory rTMS over the right DLPFC can improve recognition memory function in AD patients. They also suggest the importance of a new approach of non-invasive brain stimulation as a promising treatment in AD.
