Original Article

Prevalence and risk factors for canine cognitive dysfunction

syndrome in Thailand

Chutamas Benjanirut1* Chanakarn Wongsangchan2 Piyathip Setthawong2

Wittanee Pradidtan2 Suphanuch Daechawattanakul2 Kris Angkanaporn1

Abstract

Canine cognitive dysfunction syndrome (CDS) is a disease similar to Alzheimer’s in humans. This progressive neurodegenerative disease affects senior dogs, causes many behavioral changes and decreases welfare in both the dog and owner. Even with its high impact, many studies have shown CDS is underdiagnosed. The aims of this study were to investigate the prevalence of CDS in Thailand and to identify its risk factors. In this study, 622 senior dogs (seven years old and older) were randomly recruited. After an initial interview, 389 dogs were excluded from the study due to clinical and/or sensory impairment. Owners of the remaining dogs (233 dogs) completed a questionnaire that listed behavior related to CDS. Behavior was grouped by category: disorientation, interaction, sleep-wake cycle and activity and house soiling. Consequently, 122 dogs ( 5 2 .4 %) showed signs consistent with CDS. The percentage of dogs with CDS signs significantly increased with age and neutered dogs had a 2.3 fold higher odds of developing CDS than intact dogs. Sex and body weight/size did not significantly correlate with cognitive decline. The study also revealed sleep- wake cycle and activity was the most impaired behavior category. Only 30 % of the owners of dogs in the study were aware of CDS. Our study concluded that advanced age and reproductive status were the most obvious risk factors. The prevalence of CDS reported here was similar to that in previously reported findings. The questionnaire can be useful in screening for CDS. However, definitive CDS diagnosis requires observation and detailed owner feedback.

Keywords: canine cognitive dysfunction syndrome, prevalence, risk factors, Thailand 1Department of Veterinary Physiology, Faculty of Veterinary Science, Chulalongkorn University, Pathumwan, Bangkok 10330, Thailand 26th year veterinary student, Academic year 2014 *Correspondence: [email protected]

Thai J Vet Med. 2018. 48(3): 453-461. 454 Benjanirut C. et al. / Thai J Vet Med. 2018. 48(3): 453-461. Introduction impairment a fifth impairment; changes of activity (Manteca, 2011; Landsberg et al., 2012; Gonzalez- With better care and advances in clinical Martinez et al., 2013; Benzal and Rodriguez, 2016). The veterinary medicine, many companion dogs live well behavioral clinical signs in each impairment are shown and for longer. However, increased longevity brings in Table 1. There are many illnesses that can cause with it age-related illnesses. Some are part of normal similar clinical signs such as hearing loss, visual loss, aging, but some are pathological. One sickness often arthritis, arthrosis, epilepsy, neuropathic pain, overlooked, is neurodegenerative, causing cognitive renal/hepatic failure, hypothyroidism, decline and many behavioral changes. This hypoadrenocorticism, dilated/hypertrophic neurodegeneration can occur as the normal (gradual) cardiomyopathy, heart blockage or valve heart disease, aging of brain or it can happen at a faster pace, and painful diseases (Benzal and Rodriguez, 2016). resulting in canine cognitive dysfunction syndrome Accordingly, it is important for veterinarians to be (CDS or CCD) (Landsberg et al., 2012). CDS is cautious in making the diagnosis of CDS. characterized by changes in the brain that cause a It is known that this cognitive problem in old decline in cognitive function and lead to clinical dogs is a significant issue for both owners and their behavioral changes that affect a dog’s daily life dogs (Benzal and Rodriguez, 2016) and it can severely (Chapagain et al., 2018). With similar clinical signs and alter the bond between them, as with many other physiopathology to Alzheimer’s disease in humans behavioral problems. Therefore, it is essential to (Cummings et al., 1996), CDS also affects senior dogs. improve the understanding of the clinical signs of CDS, The onset may be different by breed depending on the leading to early diagnosis. Although there is presently breed’s life span, but one study has found that breed no cure for CDS early diagnosis and treatment can help does not affect the the prevalence of CDS (Salvin et al., to delay the clinical signs and improve quality of life, 2010). However, with small breeds having a longer life for both dog and owner. In Thailand, there is trivial span, it is possible to find more CDS in small breeds information of CDS in dogs. Therefore, the aims of this (Vite and Head, 2014). study are to find the prevalence of cognitive Pathophysiologicly, cognitive decline in dogs dysfunction syndrome in dog and to identify related is usually accompanied by the accumulation of - risk factors. The information in this study can be very amyloid in the brain. In the normal aging dog brain, - useful to both veterinarians and dog owners so that amyloid deposit may start to appear around the age of they may be more aware of this illness and design seven years and slowly accumulate with aging. intervention strategies. However, in CDS dogs the deposit of -amyloid is unusually excessive and faster than normal Materials and Methods (Chapagain et al., 2018). -amyloid deposit can be found in brain parenchyma and blood vessels similar 622 owners of dogs aged seven years or older to the brain of Alzheimer’s affected human patients were interviewed by our investigators during the year and it increases in both quantity and distribution with 2012. 266 dogs were selected for the study based upon age (Landsberg et al., 2013; Fast et al.,2013; Schmidt et the information provided by their owners. By clinical al., 2015). These changes correlate with the degree of evaluation these dogs were judged healthy and not to cognitive problems and oxidative damage in the brain have illness that could interfere with their everyday (Colle et al., 2000; Head et al., 2000). The study of Iwata activity, e.g., blindness, deafness, problems with et al., 2005 revealed that one of the causes of increasing movement, the urinary system, cardiovascular system, of -amyloid accumulation was the imbalance between endocrine system, or gastrointestinal system. its production and clearance. -amyloid can be cleared Investigators were pro-active when asking about by the enzyme neprilysin (NPL) and this was found to health issues of the dogs to identify any subtle sign of be 5 fold higher in normal dogs than cognitive sickness. Data to evaluate the cognitive behavior was impaired dogs (Canudas et al., 2014). Other collected by interviewing the owners using a pathophysiological changes in the CDS brain are questionnaire. A questionnaire was adapted and neuronal loss, increased ventricle size, cerebral modified from the Handbook of Behavior Problems of atrophy and perivascular changes, e.g., hemorrhage or the Dog and Cat 2nd edition (Landberg et al., 2003) and infarction in periventricular vessels (Landsberg et al., the CDS (Cognitive Dysfunction Syndrome) 2013). These changes are causally linked with the Diagnostic Aid Senior Dog Behavior History form by clinical signs found in CDS in dogs. Zoetis (https://www.zoetisus.com/products/dogs/ There are a multiple clinical signs of CDS, but anipryl.aspx). The resulting questionnaire (Table 1) most of them are non-specific and owners may contained 25 items of behavioral changes distributed misinterpret them as simply “old age impairments.” into four domains of cognitive impairment: This has led to the underdiagnoses of CDS. Salvin et al. disorientation, interaction, sleep-wake cycle and (2010) estimated the prevalence rate of CDS in old dogs activity, and house soiling. Also included in the was 14.2% while the clinical diagnosis rate was only questionnaire was the basic information about dog 1.9%. The clinical signs of CDS includes of 4 cognitive characteristics such as age, weight, sex and impairments: disorientation in the immediate reproductive state and information about owner environment; altered interactions with humans and knowledge about CDS. For data interpretation, if the other animals; sleep-wake cycle and activity dog had two or more behavioral changes (items) in a disturbances; and house soiling (Landsberg et al., domain, it was considered impaired in that domain 2003). Nevertheless, recently many researchers have (Neilson et al., 2001, Azkona et al., 2009). If the dog had separated activity disturbances from sleep-wake cycle one impaired domain, it was considered mild CDS, the

Benjanirut C. et al. / Thai J Vet Med. 2018. 48(3): 453-461. 455 dog with two impaired domains was considered relationship between basic factors (sex, reproductive moderate CDS and a dog with more than two impaired state, weight, age) and CDS was analyzed by Chi domains was considered severe CDS. square test. An odds ratio (OR) was used to measure the association between basic factors related to CDS. Statistical analysis: Data was analyzed using The SPSS statistical program (version 19.0) was used descriptive statistics. The prevalence of the behavioral and the significant difference was set at p < 0.05. changes was presented as mean percentage. The

Table 1 Questionnaires for evaluation of cognitive status in dogs

Cognitive impairment Question of behavior changes ( Items) Disorientation Does your dog wander aimlessly ? Does your dog appear lost or confused in the house or yard ? Does your dog become “stuck“ in corners, or under/behind furniture ? Does your dog stare into space or at walls ? Does your dog have difficulty finding door; stand at the hinge side of the door; stand at the wrong door to go outside?

Does your dog not recognize familiar people ? Does your dog not respond to verbal cues or name ? Does your dog appear to forget the reason for going outdoors ? Social interaction Does your dog solicit attention less often ? Is your dog less likely to stand/lie for petting (walks away) ? Is your dog less enthusiastic upon greeting ? Is your dog in need of constant contact, overly dependent, ‘clingy’ ? Sleep and Activity Does your dog sleep more (overall) in a day ? Does your dog sleep less during the night ? Has your dog’s day time sleep increased?

Does your dog have restless sleep/waking at nights ? Does your dog’s purposeful activity decrease in a 24-hour day ? Does your dog’s aimless activity decrease in a 24-hour day ? Has your dog’s responsiveness to stimuli decreased? Has your dog’s appetite increased ? Does your dog lick you or household objects ? House training Does your dog urinate in the wrong area ? Does your dog defecate in wrong area ? Does your dog urinate or defecate in the wrong area in view of the owners ? Does your dog urinate or defecate indoors soon after having been outside ? Does your dog signal less often to go outside ?

The 25 items of the questionnaire were grouped in four categories: disorientation (8 items), Social interaction ( 4 items), Sleep and Activity (9 items) House training (5 items)

was 52.3 %, with 36.9% classified as mild CDS, 9.4% as Results moderate CDS, and 6% as severe CDS (Fig. 1). Of the 622 dogs originally surveyed 233 were included in this study. The remaining dogs were Association between different factors (sex, excluded because of clinical problems and sensory reproductive state, weight, age) and CDS: There was impairment. Of the 233 dogs, 99 (42.5%) were female, no significant difference between male (53%) and 134 (57.5%) were male, 105 (45.1%) were neutered and female (51.6%) in having CDS (p= 0.8, OR=1.1) (Fig. 2). 128(54.9%) were intact. For reproductive status, there was a significant difference (p = 0.02) between intact and neutered dogs. The prevalence of behavioral changes associated with Neutered dogs had a 2.3 fold higher risk than intact cognitive dysfunction: Data obtained from 233 dogs dogs for having CDS (OR = 2.3) (Fig. 3). However, showed that the prevalence of CDS in this study group when analyzing male vs. female, focusing on each sex, only males showed significant difference in risk,

456 Benjanirut C. et al. / Thai J Vet Med. 2018. 48(3): 453-461. neutered vs. intact male (p=0.002). Neutered males had For correlation with body weight, dogs were 3.2 fold greater risk than intact males (OR = 3.2). By divided into three groups: small size (1-10 kg), medium contrast, in the female group even the neutered dogs size (11-25kg), and large size ( > 25 kg) in order to showed a relatively higher percentage of CDS (43% vs determine the effect of weight on the incidence of CDS. 33 %) with OR=1.8, but the difference was not No significant differences of CDS prevalence were significant (p=0.1) ( Fig. 3). found between these 3 groups (p=0.7) (Fig. 4).

Figure 1 CDS prevalence and its severity in senior dogs

Figure 2 CDS Prevalence in relation to sex. Stacked column shows the severity of cognitive impairment.

 

Figure 3 CDS Prevalence in relation to reproductive status. Stacked column shows the severity of cognitive impairment. * p < 0.05

Benjanirut C. et al. / Thai J Vet Med. 2018. 48(3): 453-461. 457

Figure 4 CDS prevalence in relation to weight. Stacked column shows the severity of cognitive impairment.

Figure 5 CDS prevalence in relation to age. Stacked column shows the severity of cognitive impairment. * p < 0.05

To measure correlation with age, the dogs prevalence ranged from 14.2 % to 73.5%. Neilson and were categorized into three age groups: 7-8-years-old, colleagues (2001) found that 23 % of 11-12-year-olds 9-12-years-old, and over 12 years. The result revealed and 68% of 15-16-year-old dogs in their study had that the prevalence of CDS significantly increased with impairment in more than one category. Osella et al., age (p=0.035) and severe CDS was noticeably greater in (2007) revealed that 73.5% of dogs aged 7 years or older age 12 and older than the younger age groups (Fig. 5, had impairment in more than one category. Table 2). Nevertheless, in two other surveys, investigators For the prevalence of clinical signs in CDS, it found CDS prevalence was only 22.5 % in 9-year-olds was found in this study that among the impairment and older (Azkona et al., 2009) and only 14.2% in 8- categories, sleep-wake cycle impairment was found year-olds and older (Salvin et al., 2010). more frequently than other impairments (Fig. 6). However, one thing common to all these and Regarding owner awareness of CDS, based the present study was the positive correlation of age upon initial interview, only 30.39 % of the 622 owners related to an increasing prevalence of CDS and severity knew about CDS (Fig. 7). (Table 2). In this study we found that dogs in the 12- year-old and older group had the highest percentage of Discussion severe CDS (16% comparing to 4% of the other two groups, Fig 6). Our data from dogs the age range 7-12-years- With the increasing incidence of CDS it is old and older provided data on the prevalence of important to identify risk factors. Information on these behavioral changes related to cognitive dysfunction. factors remains unclear. In our study, we had The prevalence in this study group was 52.3% (had postulated that large-sized breeds might have higher impairment in one or more category). Studies on prevalence of CDS, as there had been a study showing prevalence of CDS has been performed by many a strong relationship between size and aging rate, researchers over the years in different countries and namely, large dog breeds aged faster and died younger settings, e.g., age of dogs that were studied or the than small dog breeds (Kraus et al., 2013). However, method of survey. This might be responsible for the our study did not find that size or body weight had an variation in the percentage of CDS. The reported

458 Benjanirut C. et al. / Thai J Vet Med. 2018. 48(3): 453-461. effect on the prevalence or severity of CDS. This result Therefore, the discrepancy of the results among these is similar to the data of Fast et al., (2013). On the other studies may be because there was a large variation in hand, Azkona et al., (2009) found that small sized longevity of different dogs breeds (O'Neill et al., 2013) breeds had a higher risk than large breeds. Further, a or a variation of age at which aging begins relative to recent study by Katina et al. (2016) reported a greater breed, size, and weight of the dog (Szabó et al., 2016). prevalence of CDS in medium/large breeds than small Other researchers have made different suggestions in sized breeds in the age group of 11-13 years but this matter, e.g., Golini et al. (2009) indicated 7 years as reported no difference in the age group of 8-11 years. the onset of senility while Neilson et al., (2001) In these prevalence studies, all the dog population suggested 11 years. were randomly selected without regard to breed.

Table 2 Age and prevalence of CDS in multiple studies

Katina et al. 8-11 years 11-13 years Over 13 years Small breed 13% 41% 87% Medium/large breed 16% 55% 100%

Salvin et al. 8-10 years 10-12 years 12-14 years Over 14 years 3.40% 5% 23.30% 41%

Azkona et al. 9-11 years 12-14 years 15-17 years Small breed 22.70% 32.70% 50% Medium/large breed 10.30% 26.90% 40%

Neil et al. 11-12 years 15-16 years 23% 68%

Present study 7-8 years 9-12 years Over 12 years 43% 53% 68%

Figure 6 Percentage of senior dogs showing behavioral changes in each category

Figure 7 Percentage of owners’ awareness of CDS

Benjanirut C. et al. / Thai J Vet Med. 2018. 48(3): 453-461. 459 For the effect of sex and reproductive state, in but with all studies to date the risk factors of CDS are this present study there was no difference in the still inconclusive. prevalence of CDS between male and female, similar to the result from Fast et al. (2013), while another study Acknowledgements indicated the female had more risk of developing CDS (Azkona et al., 2009). With reproductive status we This study was financially supported with a found that neutered dogs had a higher risk than intact funding for special project and research grant from the dogs, similar to the results of Azkona et al., (2009). Faculty of Veterinary Sciences, Chulalongkorn However, when we compared neutered and intact University. We would also like to thank Prof. Dr. females and neutered males and intact male, only Ronald L. Hullinger, Purdue University (Indiana, neutered males showed a higher risk than intact male. USA) for his valuable comments and review of this Similarly, Hart et al., (2001) found neutered males were manuscript. more likely than intact dogs to progress from mild impairment to severe impairment. On the other hand, Conflict of Interest: The authors declare no conflict of Katina et al., (2016) found no contribution of sex and interest. reproductive status to CDS progression, but suggested it was possible that the uneven distribution of neutered References vs. intact dogs might have influenced this outcome in Azkona G, García-Belenguer S, Chacón G, Rosado B, their study. Because of these contrasting results, the León M and Palacio J 2009. Prevalence and effect of sex hormones on canine CDS is still unclear. risk factors of behavioural changes associated However, review articles on AD in human have with age-related cognitive impairment in indicated that age-related loss of estrogen in women geriatric dogs. J Small Anim Pract. 50(2)87–91. and testosterone in men are risk factors for AD and Bain MJ, Hart BL, Cliff KD and Ruehl WW 2001. both hormones exert many neuroprotective actions Predicting behavioral changes associated related to several neurodegenerative conditions with age-related cognitive impairment in (Barron and Pike, 2013; Vest and Pike, 2013; Pike, 2017). dogs. J Am Vet Med Assoc. 218(11):1792-1795. Therefore, it is possible that sex hormones will have the Barron AM and Pike CJ 2013. Sex hormones, aging, and same effect on canine CDS. Nevertheless, more study Alzheimer’s disease. Front Biosci (Elite Ed). needs to be done to confirm their importance in this 4: 976–997. matter. Benzal AS and Rodriguez AG 2016. Recent The most significant category was sleep-wake developments in canine cognitive cycle and activity impairment which is also one of the dysfunction syndrome. Pet Behavior most frequent complaints by dog owners in Thailand. Science.1:47-59. However, the study by Azkona et al., (2009) showed Canudas J, Insua D, Sarasa L, González-Martínez Á, the most impaired category to be social interaction and Suárez ML, Santamarina G, Pesini P and house training. We suggest the differences in these Sarasa M. 2014. Neprelysin is poorly reported findings relate to how dogs are raised in expressed in the prefrontal cortex of aged different cultures and countries. For example, in dogs with canine cognitive dysfunction Thailand most dogs are raised outdoors without house syndrome. Int J Alzheimers Dis. 2014: 483281. training and have less social interaction with humans doi: 10.1155/2014/483281. than in the Western countries, therefore the behavioral Chapagain D, Range F, Huber L and Viranyi Z 2018. problems in these categories were lower. Cognitive aging in dogs. Gerontology. Lastly, considering the owner awareness of 64(2):165-171. CDS in Thailand, we found that only one-third of the Colle AA, Hauw JJ, Crespeau F, Uchihara T, Akiyama owners in this study knew about CDS. This low H, Cheeler F, Pageat P and Duykaerts C 2000. percentage is important as an alert to veterinarians to Vascular and parenchimal Aaˆ deposition in raise awareness and provide information of this the aging dog: correlation with behaviour. disease to clients/owners. As CDS progression can be Neurobiol. Ag. 21(5):695–704. delayed with early diagnosis, with good knowledge, Cummings BJ, Head E, Ruehl W, Milgram NW and owners will be able to notice the problems sooner and Cotman CW 1996. The canine as an animal get dogs to veterinarians. Understanding in CDS will model of human aging and dementia. help owners understand the behavioral changes in Neurobiol Aging. 17(2): 259-268. their elderly dogs. This will be able to preserve the Fast R, Schütt T, Toft N, Møller A and Berendt M 2013. bond between them and decrease the request for An observational study with long-term euthanasia and relinquishment problems. follow-up of canine cognitive dysfunction: In conclusion, these findings about canine clinical characteristics, survival, and risk CDS in Thailand reveal there is a high percentage of factors. J Vet Int Med. 27(4):822–9. senior dogs at risk of developing CDS. Veterinarians Golini L, Colangeli R, Tranquillo V and Mariscoli M should be aware of this problem and include a CDS 2009. Association between neurologic and screening questionnaire in senior dog yearly cognitive dysfunction signs in a sample of preventative health examinations. This could be an aging dogs. J Vet Behav Clin Appl initial tool to help both owner and veterinarian to Res. 4(1):25–30. identify the early stage of CDS. However, to confirm a González-Martínez Á, Rosado B, Pesini P, García- diagnosis of CDS, further examination is needed. There Belenguer S, Palacio J, Villegas A, Suárez ML, are several potential risk factors that may be involved,

460 Benjanirut C. et al. / Thai J Vet Med. 2018. 48(3): 453-461. Santamarina G and Sarasa M 2013. Effect on Szabó D, Gee NR and Miklósi Á 2016. Natural or age and severity of cognitive dysfunction on pathologic? Discrepancies in the study of two simple tasks in pet dogs. Vet J.198(1): 176- behavioral and cognitive signs in aging 181. family dogs. J Vet Behav Clin Appl Res.11:86– Hart BL 2001. Effect of gonadectomy on subsequent 98. development of age-related cognitive Vest RS and Pike CJ 2013. Gender, sex steroid impairment in dogs. J Am Vet Med Assoc. hormones, and Alzheimer’s disease. Horm 219(1): 51–6. Behav. 63(2): 301–307. Head E, Thornton PL, Tong L and Cotman CW 2000. Vite CH and Head E 2014. Aging in the canine and Initiation and propagation of molecular feline brain. Vet Clin North Am Small Anim cascades in human brain aging: insight from Pract. 44(6): 1113-1129. the canine model to promote successful aging. Prog. Neuropsychopharm. Biol. Psychiat. 24(5):777–786. Iwata N, Higuchi M and Saido TC 2005. Metabolism of amyloid-β peptide and Alzheimer ́s disease. Pharmacol Ther. 108(2): 129-148. Katina S, Farbakova J, Madari A, Novak M and Zilka N 2016. Risk factors for canine cognitive dysfunction syndrome in Slovakia. Acta Vet Scand. 58:17. Kraus C, Pavard S and Promislow DE 2013. The size- life span trade-off decomposed: why large dogs die young. Amer Nat. 181(4):492–505. Landsberg GM, Hunthausen W and Ackerman L 2003. The effects of aging on the behavior of senior pets. In: Handbook of Behavior Problems of the Dog and Cat. 2nd ed Edinburgh: Saunders p. 269–304. Landsberg GM, Hunthausen W and Ackerman L 2013. The effects of aging on the behavior of senior pets. In: Behavior Problems of the Dog and Cat 3rd ed. Edinburgh: Saunders p. 211-235. Landsberg GM, Nichol J and Araujo JA 2012. Cognitive dysfunction syndrome. A disease of canine and feline brain aging. Vet Clin North Am Small Anim Pract. 42(4): 749-768. Manteca X 2011. Nutrition and behavior in senior dogs. Top Companion Anim Med. 26(1): 33-36. Neilson JC, Hart BL, Cliff KD and Ruehl WW 2001. Prevalence of behavioral changes associated with age-related cognitive impairment in dogs. J Am Vet Med Assoc. 218(11):1787– 1791. O'Neill DG, Church DB, McGreevy PD, Thomson PC and Brodbelt DC 2013. Longevity and mortality of owned dogs in England. Vet J.198(3):638–643. Osella MC, Re G, Odore R, Girardi C, Badino P, Barbero R and Bergamasco L 2007. Canine cognitive dysfunction syndrome: prevalnce, clinical signs and treatment with a neuroprotective nutraceutical. Appl Anim Beh Sci.105(4):297–310. Pike CJ 2017. Sex and the development of Alzheimer’s disease. J Neurosci Res. 95(1-2): 671–680. Salvin HE, McGreevy PD, Sachdev PS and Valenzuela MJ 2010. Under diagnosis of canine cognitive dysfunction: a cross-sectional survey of older companion dogs. Vet J. 184(3):277–81. Schmidt F, Boltze J, Jäger C, Hofmann S, Willems N, Seeger J, Härtig W and Stolzing A 2015. Detection and quantification of β-amyloid, pyroglutamil Aβ, and tau in aged canines. J Neuropathol Exp Neurol. 74(9): 912-923.

Benjanirut C. et al. / Thai J Vet Med. 2018. 48(3): 453-461. 445619

บทคัดย่อ

ความชุกและปัจจัยเสี่ยงของกลุ่มอาการ ภาวะสมองเสื่อมของสุนัขในประเทศไทย

จุฑามาส เบ็ญจนิรัตน์1 ชนากานต์ วงศ์แสงจันทร์2 ปิยะทิพย์ เศรษฐวงศ์2 วิทย์ธนี ประดิษฐ์แท่น2 ศุภนุช เดชาวัฒนากุล2 กฤษ อังคนาพร1

กลุ่มอาการ ภาวะสมองเสื่อมของสุนัข (Canine cognitive dysfunction syndrome) CDS เป็นโรคในสุนัขที่เทียบเคียงได้กับ โรคอัลไซเมอร์ในมนุษย์ โรคนี้ท าให้เกิดการเสื่อมลงของระบบประสาทอย่างรวดเร็วเกินกว่าปกติในสุนัขวัยชรา และทาให้สุนัขมีพฤติกรรมที่ เปลี่ยนแปลงไป ส่งผลกระทบต่อสวัสดิภาพของทั้งสุนัขและเจ้าของ ถึงแม้โรคนี้จะส่งผลกระทบอย่างมากดังที่กล่าวมา แต่หลายๆ การศึกษาได้ แสดงให้เห็นว่า การวินิจฉัย CDS ต่ ากว่าความเป็นจริง จุดประสงค์ของการศึกษาครั้งนี้คือ การหาความชุกและปัจจัยเสี่ยงของ CDS ในประเทศ ไทย ในการศึกษาครั้งนี้ได้ท าการสุ่มสุนัขวัยชรา อายุ 7 ปีขึ้นไป จ านวน 622 ตัว จากนั้นได้ท าการสัมภาษณ์เจ้าของเพื่อคัดเลือกเฉพาะสุนัขที่ีมี สุขภาพดีและไม่มีปัญหาทางประสาทรับรู้ต่างๆ จากผลการสัมภาษณ์มีสุนัข 233 ตัว ที่ผ่านเกณฑ์และเจ้าของสุนัขได้ท าแบบสอบถามที่มี ค าถามเกี่ยวกับพฤติกรรมที่เกี่ยวข้องกับ CDS โดยพฤติกรรมเหล่านี้จะถูกแบ่งออกเป็น 4 กลุ่มใหญ่ คือ disorientation (การหลงทิศทาง สับสน หลงลืม), interaction (ปฏิสัมพันธ์กับมนุษย์และสัตว์เปลี่ยนแปลงไป), sleep-wake cycle and activity (วงจรการนอนหลับและ กิจกรรมเปลี่ยนไป) และ house soiling (การขับถ่ายไม่เป็นที่) ผลการศึกษาพบว่าสุนัขจ านวน 122 ตัว คิดเป็น 52.4% แสดงอาการของ CDS ร้อยละของสุนัขที่แสดงอาการของ CDS เพิ่มขึ้นตามอายุ และสุนัขที่ท าหมันมีความเสี่ยงที่จะพบอาการ CDS มากกว่าสุนัขที่ไม่ท าหมัน 2.3 เท่า อย่างไรก็ตามเพศ น้ าหนัก/ขนาด ไม่มีความสัมพันธ์กับการพบอาการของ CDS การศึกษาครั้งนี้สรุปได้ว่า อายุที่เพิ่มขึ้นและการท าหมันเป็น ปัจจัยเสี่ยงที่เด่นชัดในการเกิด CDS ความชุกของ CDS ในการวิจัยครั้งนี้ยังค่อนข้างใกล้เคียงกับการศึกษาที่ผ่านๆ มา แบบสอบถามสามารถที่ จะใช้เป็นเครื่องมือเบื้องต้นที่เป็นประโยชน์ในการตรวจหา CDS อย่างไรก็ตามการยืนยันผลการวินิจฉัย CDS จะต้องมีการตรวจเพิ่มเติมพร้อม กับการสอบถามข้อมูลโดยละเอียดจากเจ้าของ

ค าส าคัญ: ความชุก ปัจจัยเสี่ยง ประเทศไทย ภาวะสมองเสื่อมของสุนัข 1ภาควิชาสรีรวิทยา คณะสัตวแพทยศาสตร์ จุฬาลงกรณ์มหาวิทยาลัย กรุงเทพฯ 10330 2นิสิตชั้นปีที่ 6 ปีการศึกษา 2555 คณะสัตวแพทยศาสตร์ จุฬาลงกรณ์มหาวิทยาลัย กรุงเทพฯ 10330 *ผู้รับผิดชอบบทความ E-mail: [email protected]