The generation of dentate granule cells (GCs) in the adult hippocampus declines with age due to reduced progenitor proliferation, slower maturation, and decreased survival of newborn neurons. We previously showed that in 8-month-old mice, 40 Hz audiovisual stimulation (AuViS), a non-invasive intervention known to reduce amyloid-β and improve memory in Alzheimer’s models, enhances neurogenesis and accelerates neuronal maturation. In 12-month-old mice (12M), where neurogenesis is further compromised, AuViS still promotes neuronal differentiation at the expense of astrogenesis. Here, we examined progenitor cell proliferation in the dentate gyrus of 12M mice exposed to chronic AuViS. Animals were divided into three groups: (1) control, (2) 4 weeks of AuViS followed by 3 weeks without stimulus, and (3) continuous AuViS for 7 weeks. Ki67 immunostaining revealed that prolonged AuViS reduced the number of proliferating cells. This decline may arise from a depletion of the neural stem cell pool after sustained stimulation. These findings highlight both the potential and the complexity of AuViS as a modulator of neurogenesis in aging. They also raise the possibility that therapeutic protocols might require spacing of stimulation sessions to preserve the progenitor pool and sustain long-term efficacy. Ongoing and future experiments will further clarify the underlying mechanisms and optimize stimulation strategies.