With an ever-increasing population of Alzheimer’s disease (AD) patients worldwide, a noninvasive treatment for AD is needed. In this paper, the application of repetitive transcranial magnetic stimulus (rTMS) as a treatment for patients with probable AD is compared to the application of rTMS as a treatment for depression. Comorbidity of depression and dementia is discussed, as well as possible links between the two diseases. The possible confounding antidepressant effects of rTMS on cognitive improvements in AD patients are discussed. 1. Introduction In 2010, there were an estimated 35.6 million people in the world suffering from dementia [1]. This is an increasing problem; 65.7 million dementia cases are expected by 2030 and 115.4 million by 2050. The cause of 50%–75% of dementia cases is Alzheimer’s disease (AD). This growing problem presents a pressing need for AD treatments. Repetitive transcranial magnetic stimulation (rTMS) is a noninvasive technique that has been used as a treatment for several major neurological and psychotic disorders such as Parkinson’s disease, depression, and schizophrenia in the last decade [1]; it is currently being investigated as a treatment for AD. The process of applying rTMS involves a rapidly varying magnetic field, which can be used to modulate the firing of neurons on the outer surface of the brain [2]. It has been shown that rTMS can either stimulate or inhibit cortical areas within the focal area of the coil [3, 4]. Often, rTMS treatments can be separated into two groups: high-frequency rTMS (10–20？Hz) and low-frequency rTMS (1？Hz) [4]. The high-frequency rTMS is generally considered to be more excitatory, while the low-frequency rTMS is inhibitory, although this may vary between individuals [5]. The mechanism through which rTMS affects the brain is thought to be long-term potentiation/depression (LTP/LTD) [6]. There have been a number of studies investigating rTMS as a treatment for cognitive decline in AD. A comprehensive review of these studies can be found in [7, 8]. These papers conclude that there is promise for the use of rTMS to treat AD, but that further study is required. Specifically, action and object naming has been shown to improve during rTMS treatments [9, 10], auditory sentence comprehension is improved up to eight weeks after rTMS treatment [11], high-frequency rTMS can improve cognitive skills in patients for up to 3 months [12], and rTMS combined with cognitive training produces long-lasting improvements in a variety of cognitive measures [13]. While these results are promising, they are still
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